Difficult airway, head & neck/ENT

Question 1

What are some disadvantages of tubeless anaesthesia?

Answer 1

aspiration risk
harder to control & monitor FiO2, EtCO2 & anaes gases (if used), it relies on a TIVA technique
mobile surgical field; less precision & harder for laser surgery
harder to control pt depth of anaesthesia & mobility
best for short, uncomplicated cases

Question 2

What are the steps in maximising conditions for FMV?

Answer 2

Head position
2-hand 2-person technique
ensure no foreign body
Oral/nasal airway
Mouth opening (ensure ADEQUATE ANAESTHETIC DEPTH/m relaxation)
Perioral area (remove moisturiser/airway lubricant to assist mask grip)

Question 3

What are the steps when encounter difficult FMV?

Answer 3

-Ensure integrity of circuit (will have confirmed during level 3 check)
-Continue high-flow 100% oxygen (will have pre-oxygenated)
-maximise conditions for FMV
-if still not able to achieve good ventilation, pause & consider option of waking pt (easier if factored into anaesthetic plan eg. gaseous induction or gradual onset TIVA) but if given full induction dose, likely committed to securing airway
-verbalise concerns, call for help, delegate- ask someone to watch time elapsed, SpO2 & etCO2 monitors to help prevent prolonged hypoxia- eek assistance from other criteria care specialists, surgeons, nursing staff & encourage room to speak up if concerns (if airway manoeuvres in one pathway substantially attempted without success, escalate the emergency response)
-Consider laryngospasm or other causes of elevated airway pressure if difficulty emptying reservoir bag on attempted ventilation
-If reservoir bag has poor refilling & low circuit pressure/ongoing facemask leak, ensure adequate depth to facilitate airway control
-Attempt SGA insertion- UP TO 3 attempts (2 in obstetrics), trying different size/type
-Revert back to FMV while prepare for intubation (if airway manoeuvres in 2 pathways substantially attempted without success & FMV fails again, CICO READY)
-Confirm good muscle relaxation & continue FMV- attempt intubation- if unsuccessful, move to difficult intubation protocol & have CICO equipment open (CICO SET)

Question 4

What are some strategies I can factor into my anaesthetic plan to allow for test ventilation in suspect difficult airway?

Answer 4

Gaseous induction or gradual onset TIVA

Question 5

What’s the sequence of events when unanticipated difficult intubation occurs?

Answer 5

-Call for help, communicate, delegate (useful to have someone monitoring SpO2, EtCO2 & elapsed time until rescue complete)
-Revert to FMV, get difficult airway trolley, consider options (wake or continue, plans for next steps & contingencies)
-Ensure adequate anaesthetic depth & muscle relaxation
-Maximise conditions for optimal laryngeal view & utilise adjuncts as needed
-Up to 3 optimised intubation attempts (2 for obstetrics)- try videolaryngoscopy or hyper-angulated blade
-If unsuccessful, mobilise CICO resources (CICO READY)- verbalise concerns, delegate someone to watch the time/SpO2/etCO2 & encourage room to speak up if concerns (delegate help from other crit care specialists, surgeons & nursing staff.
(If airway manoeuvres in one pathway substantially attempted without success, escalate the emergency response)
-Up to 3 SGA attempts (2 for obstetrics)- try diff size or type
-If unsuccessful, ie. airway manoeuvres in 2 pathways substantially attempted without success, CICO SET (equip open & ready)
-One final maximised attempt at FMV- if SpO2 falling & EtCO2 not detectable, Optimise position & initiate CICO GO (infraglottic rescue with scalpel/bougie or needle/cannula)

Question 6

What are options to optimise laryngeal view? What adjuncts could use?

Answer 6

Position: neck flexion & head extension
Adjust cricoid
External laryngeal manipulation to flatten vestibule axis
Try long or straight blade
Videolaryngoscope

Bougie
Introducer
Stylet

Question 7

Why is straight blade useful in paeds? Examples of straight blades? Problem often encountered when using the straight blade via paraglossal approach?

Answer 7

Directly lift epiglottis- useful as children have long floppy epiglottis
Miller & Wisconsin blades- straight blades w curved tip
Magill blade- straight blade with U-shaped cross-section

May have trouble passing tube- which is why the straight blade with U-shaped channel created, to facilitate tube passage

Question 8

How is a Kessel blade different to standard Macintosh? And the Polio blade?
When are the Kessel & polio blades useful?

Answer 8

Blade connects at 110 degree angle vs Macintosh which connects at 90 degrees
Polio connects at 135 degrees
May be used with short handle in obese/obstetrics/barrel chest pt (those pts w limited antesternal space)

Question 9

What’s a McCoy blade? What used for?

Answer 9

Like a Macintosh but with distal tip which can be flexed by a lever on the handle to displace larynx forward

Particularly useful for posterior column pathology creating limited neck extension (eg. RA, MILS). NOT useful if grade 4 view (as it indirectly lifts epiglottis so need to access vallecula)

Question 10

IT_AM 1.7: Describe the optimal patient position for intubation
How may the “sniffing position” optimise the laryngoscopy view?
How to tell externally?
How may obesity make this alignment difficult?
Where do the primary & secondary curves meet? how does the sniffing position help this?

Answer 10

sniffing position: axes (oral, pharyngeal, laryngeal axes) all align for enhanced airway patency
Head extension flattens primary curve, neck flexion flattens secondary curve, both these maneouvres improve line-of-sight to the glottis, facilitating intubation
Having the EAM & sternal notch aligned on horizontal plane creates optimal “sniffing” position
Fat pad @ upper back makes it difficult to achieve the head elevation w single pillow- need to “ramp” to optimise laryngoscopy view
They meet in the laryngeal vestibule. Sniffing position brings the vestibule axis flat or slightly down-sloping, optimising laryngeal view & facilitating passing of the ETT.

Question 11

During which stage of approaching the airway does the posterior column become relevant? Which pathologies or circumstances can impact posterior column?

Answer 11

Positioning of the head & neck before attempting laryngoscopy, relies on mobility of the ocipito-atlanto-axial complex
RA, ankylosis, prev C-spine fixation, halo fixation, manual in-line stabilisation

Question 12

What’s the middle column? Which pathologies or circumstances can impact middle column?

Answer 12

The air passage
Foreign bodies, laryngeal oedema, epiglottis/abscess, tumours, redundant pharyngeal tissue
Ax via CT/MRI/nasendoscopy
Hx of stridor, hoarseness suggests middle column pathology

Question 13

Is obesity a risk factor for middle passage obstruction?

Answer 13

Not unless there’s adipose deposition in the pharyngeal walls, with symptoms of OSA

Question 14

What comprises the anterior column? During which part of approach to airway can anterior column abnormalities impact? Which pathologies/circumstances impact the anterior column?

Answer 14

submandibular space & glottal muscles
Laryngoscopy when lift/displace anterior column structures to view glottis (dynamic phase)
Anything that reduces the size/volume of the anterior column (eg. retrognathia) or compliance of anterior column structures (previous radiotherapy/ infections/ fluid collections/ oedema/ pus/ burns/ tumour/ haemorrhage)
Buck teeth= relative micrognathia
Large tongue

TMJ ROM

Question 15

How to assess the posterior column?
What laryngoscope blade may be useful if the pt has posterior column abnormalities?

Answer 15

Neck ROM (history clue)

Videolaryngoscope (hyperangulated/D-blade better)
McCoy blade
LMA + FOB + aintree
I LMA

Question 16

How to assess the middle column? Which laryngoscope blades may be most helpful for middle column pathologies?

Answer 16

History/exam (nasopharyngoscopy)/investigations (CT/MRI)

Macintosh- Videolaryngoscopy with standard Mac or D blade depending on pathology location
LMA + FOB + aintree

NOT the iLMA as it’s got a fixed angle

Question 17

How to assess the anterior column? Which laryngoscope blades/adjuncts may be most helpful for anterior column pathologies?

Answer 17

TMD
inciso-TMJ distance
jaw protrusion (upper lip bite test higher specificity & interobserver variability cf mallampatti), presence of overbite
mallampati

Straight blade is narrow, provides better displacement of tissues & overcomes issue of elevating the epiglottis via the hyoepiglottic ligament when overcoming non-compliant tissues

Videolaryngoscope (angle of blade depends on the location of the pathology- NOT McCoy blade (more difficult to deploy via hyoepiglottic ligament w anterior column pathology)

LMA + FOB + aintree

NOT iLMA (has a fixed curve)

Question 18

What do you require when using a D-blade without channel? What step is useful when about to pass the tube? From what angle may it be useful to pass the introducer?
What may be an issue when passing the tube with a hyperangulated blade? strategies?

Answer 18

Introducer (eg. stylet) required because the blade follows the primary curve in the midline
Tilt the laryngoscope slightly down so the larynx is in the upper part of the screen so can see the approaching tube & introducer & correct angle for passage. Also, this movement brings the larynx slightly closer to the tube, allowing it to pass more naturally into the glottis.
Introduce the introducer/tube from the R) corner of the mouth, so it approaches posteriorly & doesn’t obstruct the view of the glottis until passage through cords.
Tube may meet anterior wall- use external laryngeal manipulation which may flatten the vestibule axis, turning the tube/introducer 90 degrees to the R) at the level of the cords, stylet with “straight to cuff” angulation of no >35 degrees

Question 19

When are the hyperangulated blades useful?

Answer 19

Anterior or posterior column pathology, where the primary curve can’t be modified easily (eg. lack of tissue compressibility) or the secondary curve is unfavourably positioned

Question 20

What does the Storz C-mac D-blade have which is particularly useful?

Answer 20

Channel on the left for bougie, which can otherwise be tricky to pass with hyperangulated blades

Question 21

What do do if tube won’t pass cords? or over bougie?

Answer 21

Gentle turn to the R) at first, then try to the L) (chances are tube stuck in piriform fossa)

Question 22

What are the considerations to optimise @ each lifeline?

Answer 22

manipulations
adjuncts
size/type
suction/O2 flow
muscle tone

Question 23

If can’t palpate the cricothyroid membrane, where go for CICO?

Answer 23

aim for tracheal midline lower down

Question 24

What are the settings for jet ventilator or flow-regulated insufflation devices to attach for the 14g cannula technique? How long inflate for & wait for sats response? how long are subsequent insufflations?

Answer 24

1 bar (14.5 psi) or 15L/min

4s, wait 30 secs for SpO2 response, subsequent insufflations 2 seconds, titrated to SpO2

Question 25

What size scalpel use for scalpel bougie CICO technique? What size ETT do we railroad over the bougie?

Answer 25

size 10 blade

size 6 ETT

Question 26

What’s the process for surgical cricothyroidotomy?

Answer 26

6-8cm vertical incision from sternal notch, blunt finger dissect strap muscles & expose trachea, use scalpel bougie technique

Question 27

What’s the approach to laryngospasm?

Answer 27

turn on high-flow 100% O2
cease all stimulation
remove airway devices, gently suction
Apply firm jaw thrust, gentle CPAP, consider oral airway (which MAY help w providing CPAP, despite the fact that stimulating airway devices which may contribute to spasm should be removed)

If the laryngospasm continues & desaturation occurs:
-call for help (early, particularly in paeds), communicate & delegate (sux 1mg/kg IV, 2-4mg/kg IM/IL/IO (best if pre-drawn) & ETT prep)
-deepen anaesthesia (in paeds, rapid development of hypoxia usually precludes this, may be more appropriate to proceed immediately to intubation sans relaxation)
-give sux & continue CPAP
-if laryngospasm doesn’t improve, secure airway w intubation, consider IV atropine 10-20mcg/kg IV for the Rx of associated bradycardia

Question 28

While laryngospasm eventually “breaks” w sufficient time & hypoxia (!).. what are some big problems with getting to that point?

Answer 28

bradycardia
cardiac arrest
regurg
pulm oedema

Question 29

What’s a wise move, prior to emergence, in a pt who’s had laryngospasm?

Answer 29

stomach deflation, since forced inflation attempts in complete laryngeal obstruction will inflate the stomach

Question 30

What may be the right approach to managing laryngospasm in a rapidly desaturating child?

Answer 30

immediate intubation sans relaxation

Question 31

What’s the approach to elevated airway pressure?

Answer 31

-Manually ventilate to confirm high pressure
-Rapidly exclude light anaesthesia/inadequate muscle relaxation
-systematically check the circuit, valve & ventilator for kinking/obstruction
-if suspect auto-PEEP, look for elevated end-exp alveolar pressure & persistent exp flow when next breath commences
-replace circuit w self-inflating resuscitator connected DIRECTLY to airway device (if the problem persists, this isolates the issue to the airway or the pt)
-check airway position & patency, suction full length of the tube, use a bronchoscope to confirm. If pressure remains high, examine pts airway. Only then, if remain in any doubt about the airway, should it be replaced- if was using an LMA, consider intubating
-if pressure remains high after assessing +/- changing the airway, problem must be with the pt- examine pts resp system, call for assistance
-review common pt causes:

Question 32

What are common pt causes of high airway pressure? What may assist in raising index of suspicion for a particular cause?

Answer 32

-bronchospasm (incl due to anaphylaxis)
-laryngospasm (in pt w LMA)
-chest wall rigidity
-oedema
-PTx
-Haemothorax

Consider the timing of the event (eg. recent tube adjustment, CVC insertion, drug admin, position change, pneumoperitoneum, surgical intervention)

Question 33

What’s the approach to severe bronchospasm?

Answer 33

-Call for help, communicate & delegate (including drawing up drugs)
-review airway placement, patency
-hand ventilate w 100% O2, deepen anaesthesia unless suspect anaphylaxis or if haemodynamics don’t allow
-give in-circuit salbutamol & ipratropium bromide
-monitor progress w EtCO2 waveform & airway pressures
-set I:E ratio for long expiratory phase, intermittently disconnect & use low pressure PEEP to reduce hyperinflation
-consider IV fluids, art line & serial ABGs
-give IV bolus salbutamol or Adr, commence an infusion if spasm persists
-use hydrocortisone (or methylated) & Mg++ as adjuncts
-depending on the severity & response to therapy, consider whether to proceed w OT & contact ICU

Question 34

What are the 5 main causes of bronchospasm?

Answer 34

4 a’s & an F

Anaphylaxis
Asthma exac
Aspiration
Airway malposition
Foreign body

Question 35

What are the drug doses of Adr & salbutamol (IV) for bronchospasm?

Answer 35

Adr:
0.1-1mcg/kg bolus, titrated to haemodynamics, then infusion at rate 0.1mcg/kg/min, which in mLs/hr equivalent to wt/10 (eg. 7mL/hr=7cmg/min (what we want for 0.1mcg/kg/min) of 3mg/50mL Adr for 70kg male)

Adult salbutamol:
250mcg IV over 5 mins
infusion 200mcg load over 1 min, then 5-25mcg/min

Chn 2-12yo
Salbutamol infusion loading of 5mcg/kg/min (max 200mcg/min) for 1 hr, then 1-2mcg/kg/min (max 80mcg/min)

Question 36

Is there evidence to support use of salbutamol over Adrenaline for bronchospasm?

Answer 36

No

Question 37

In the NAP4, what proportion of airway-related deaths in anaesthesia were a consequence of aspiration?

Answer 37

Over 50%

Question 38

What are some pt, surgical & anaesthetic factors for aspiration?

Answer 38

Pt: unfasted, obesity, pregnant/immediately postpartum, trauma, opioids, diabetes/other cause of delayed gastric emptying, LOS incompetence (eg. hiatus hernia), known GORD

Surg: upper GI, lithotomy, head down, laparoscopy, cholecystectomy

Anaes: prolonged OT, SGA, light anaesthesia, PPV, difficult airway

Question 39

What are the steps for management of aspiration?

Answer 39

1. call for help, communicate, delegate
2. head down, consider L) lateral
3. remove airway, suction the pharynx
4. intubate & suction bronchial tree
5. (ideally AFTER steps 1-4): ventilate w 100% O2 then titrate to normal SpO2
6. If severe aspiration, proceed only w emergencies
7. empty stomach & ensure adequately reversed before emergence
8. consider ICU/HDU admission

Question 40

Should cricoid be used when intubating a pt who has aspirated?

Answer 40

It can be, but not during active vomiting or regurgitation

Question 41

What are the conditions for likely being able to avoid ICU following an intra-op aspiration event?

Answer 41

at 2 hrs post aspiration, if the pt isn’t symptomatic, the chest is clear & the SpO2 are normal, however, if PARTICULATE MATTER (indicates more severe aspiration), ICU required for post op management. Can inspect the bronchial tree w bronchoscope prior to extubation to Ax for particulate matter.

Question 42

Are steroids & antibiotics indicated after an aspiration event?

Answer 42

Steroids haven’t been shown to impact outcome or mortality after aspiration
Antibiotics are NOT indicated in the short-term management of aspiration UNLESS pneumonia develops

Question 43

What are the standard internal diameters for airway equipment?

Answer 43

15mm & 22mm

Question 44

What’s the best endotracheal cuff pressure? What are the risks of excessive cuff pressure?

Answer 44

20-30cmH2O (the usual 10mL air is generally enough to achieve this with correctly-sized tube); capillary perfusion blanched above 30cmH2O

Acute tracheal rupture, tracheal necrosis & tracheo-oesophageal fistula

Question 45

What are some differentials of a cuff pressure of zero?

Answer 45

cuff rupture, pilot balloon rupture, balloon inflation lumen occluded

Question 46

How can micro-aspiration occur, even with appropriate cuff pressure?

Answer 46

The low-pressure, high-volume cuffs have folds which allow micro-aspiration

Question 47

In what proportion of the population does the R) UL bronchus anomalously takeoff from the distal trachea?

Answer 47

0.5%

Question 48

Where should the ETT tip be sitting wrt the carina with neck neutral?

Answer 48

5cm above, which corresponds to approx T3-4 (w trachea being approx T5-6)

Question 49

What proportion of pts with head & neck cancer have a synchronous primary elsewhere in the aero digestive tract?

Answer 49

10%

Question 50

What are the main risk factors for head & neck Ca>

Answer 50

smoking, ETOH. also poor PO hygiene, exposure to wood dust, chewing tobacco & HPV

Question 51

What are some flags for airway compromise in a pt w head & neck Ca?

Answer 51

voice changes, dysphagia, orthopnoea, recent onset snoring, stridor, difficulty lying flat

Question 52

Which pre-op Ix may assist in the planning for decision re: airway strategy in a pt w head/neck Ca?

Answer 52

CT, MRI, US (to identify cricothyroid membrane prior to induction), awake FNE

Question 53

How may PFTs be useful prior to head & neck Ca surgery?

Answer 53

Flow-volume loops may be useful for differentiating upper airway obstruction from chronic airway disease.
Any reversible element could be optimised before surgery by modification of bronchodilator therapy, Rx of acute infection, trial of steroids.

Question 54

From CPET, what anaerobic threshold is associated with higher risk of cardiac complications?

Answer 54

11mL/min/kg

Question 55

How may cardiac biomarkers BNP & N-tBNP be useful in head & neck surgery workup?

Answer 55

screening for HF, independent predictors of 30-day cardiac mortality

Question 56

What may be some causes & consequences of preop malnutrition in pts w head & neck Ca?

Answer 56

poor dietary habits (eg. alcoholism), cancer cachexia, dysphagia, systemic effects of chemo, radiation mucositis.
It’s ass’d w poor wound healing, infection, incr risk postop complications.
Refeeding syndrome.
Pts w head & neck Ca should have nutritional screening & specialist dietician input.

Question 57

What are some of the effects of refeeding syndrome?

Answer 57

hormonal & metabolic changes when switch to anabolic state- hypophosphatemia, hypomagnesaemia, hypokalaemia, hypocalcemia, thiamine deficiency

Question 58

What are some of the periop considerations for pts w ETOH dependency?

Answer 58

active inpatient withdrawal Rx for at least 48hrs preop should be considered
optimise nutrition, electrolyte & haematological indices

Question 59

How to manage refeeding risk?

Answer 59

specialist dietetics input
measure serum K+, Ca++, Mg++, phosphate
administer thiamine, vit B, trace elements
rehydrate & supplement K+, Mg++, Ca++, phosphate as required
start feeding 0.0418Mj/kg/day, slowly increase, monitor potassium, calcium, magnesium & phosphate & replace as needed for 2/52

Question 60

For which procedures has the P-POSSUM been extensively validated? Which is the best calculator to predict perioperative cardiac risk for major head & neck surgery?

Answer 60

colorectal & vascular
Lee’s RCRI

Question 61

What class of surgical risk is major head & neck surgery considered?

Answer 61

Intermediate- 1-5% risk of a 30-day cardiac event

Question 62

What are some of the sequelae of radiotherapy for head & neck cancer?

Answer 62

fibrotic airway, woody/non-compliant tissue (difficult BMV & laryngoscopy), limited neck E
TMJ ankylosis
osteoradionecrosis of mandible
carotid stenosis
hypothyroidism
baroreceptor damage
poor wound healing

Question 63

What are some of the sequelae of maxillectomy & craniofacial resection for head & neck cancer?

Answer 63

difficult mask seal
difficult nasal access
temporalis contracture
TMJ pseudoankylosis

Question 64

What are some of the sequelae of floor of mouth or tongue surgery for head & neck cancer?

Answer 64

trismus
fixed, immobile tongue (difficult laryngoscopy)
limited mandibular space
increased tongue:oral cavity ratio with flap reconstruction

Question 65

What are some of the sequelae of laryngeal surgery for head & neck cancer?

Answer 65

laryngeal stenosis
impaired swallowing
aspiration risk

Question 66

What are some of the sequelae of deck dissection for head & neck cancer?

Answer 66

damage to IX, X, XII nerves
impaired swallowing
aspiration risk
VC palsy

Question 67

What factors should be established during the preop evaluation of a head & neck Ca pt?

Answer 67

A difficult airway should be anticipated, airway strategy with sequential backup plans established, there should be multi-D discussion, clear communication, appropriate equipment/assistance & coordinated team approach
What are the anatomical limitations of the lesion(s), any loco-regional or distant spread? (look at imaging/Ix)
Is facemask ventilation likely to be necessary? Difficult?
Are SGA insertion & laryngoscopy/intubation likely to be difficult?
If difficult BMV or intubation likely after induction anticipated, consider if awake technique more appropriate?
Would emergency surgical airway & FONA be feasible?

Question 68

What are the benefits of AFOI? What primary airway plan should be considered if anticipate difficult BMV/intubation but AFOI not possible?

Answer 68

Maintain airway patency, gas exchange & protection against aspiration during the intubation process
Awake tracheostomy under LA

Question 69

Is there evidence to show that the use of videolaryngoscopy reduces the number of intubation attempts, time for intubation, incidence of hypoxia or respiratory complications?

Answer 69

No, but there is evidence that it’s associated with less failed intubations & lower rates of airway trauma. BJA 2017.

Question 70

What are some benefits to using THRIVE for difficult airway?

Answer 70

provides apnoeic oxygenation, CPAP, flow-dependent dead-space flushing, prolongs apneoic window

Question 71

In which position are most head & neck Ca operations performed?
What are some other practical considerations aside from airway strategy?

Answer 71

supine with 10-15 degree head-up tilt to improve venous drainage
limited access to head & neck; require long ventilator tubing & vascular access lines, eyes protected w tapes & eye shields, moistened eye pads for laser procedures, PPP, TEDS/scuds
Large IVC + G&H for major resections (anticipate blood loss)
Other invasive access depends on pt & surg factors
Consider goal-directed fluid therapy based on CO monitoring to help avoid fluid overload in free flap transfer
Temp monitoring (often prolonged)- ideally IDC (rectal temp lags behind core), during free flap transfer the core bladder & skin temp are measured to ensure core-periphery gradient <1.5deg
Consider TIVA or volatile + remi
consider dex (antiemetic, analgesia, reduces airway oedema)

Question 72

What are some benefits of remifentanil for head & neck surgery?

Answer 72

rapidly titratable
blunts haemodynamic response during points of intense surgical stimulation
induced hypoT (in appropriate patients) may help reduce surg bleeding & improve surg field

Question 73

Is submental intubation appropriate in cancer surgery?

Answer 73

no. contraindicated- risk of creating an orocutaneous fistula.

Question 74

What are the likely benefits of oral vs nasal intubation for head & neck Ca?

Answer 74

oral intubation facilitates access to lesions of the maxilla, nasal cavity, paranasal sinuses

nasal intubation facilitates access to oral cavity

Question 75

What are anaesthetic considerations in craniofacial resection for base of skull tumors?

Answer 75

surgical approach= trans nasal or bicoronal
similar goals to neurosurgical anaesthesia:
adequate CPP (normocapnia & normotension to preserve CBF) & optimal O2 delivery while providing optimal surgical conditions
Require broad-spectrum antibiotic cover as the dura is breached & high risk contamination

Question 76

What are some complications of skull base tumor resection?

Answer 76

CSF leak, vascular injury, visual defects from injury to or ischemia of the optic nerve (require frequent postop neuro observations)

Question 77

What are the anaesthetic goals for free-flap procedures?

Answer 77

Full, hyper-dynamic circulation with increased cardiac output, incr MAP, promote peripheral VD & normothermia to maximise flap perfusion
Hct 30-35% to improve O2 transfer & red cell velocity within the microcirculation
Care w systemically administered inotropes as risk compromise flap microcirculation; generally avoid NAdr (predominantly VC), dobutamine preferred as inodilator but may be limited by tachycardia

Question 78

which pt factors are contraindictions for free-flap transfer & which conditions may require particular pre-op Ix/optimisation?

Answer 78

sickle cell disease & untreated polycythemia rubra vera (flap failure rate high from microcirculatory “sludging” & hype- coagulability)
If active vasculitis (w collagen vascular disease), the rate of anastomotic thrombosis is high so specialist referral & Rx required pre-op
For PVD, MRI angiography indicated to determine patency of donor vessels in the fibular free flap for mandibular recon

Question 79

What are some anaes considerations for parotid surgery?

Answer 79

preservation of facial nerve; nerve monitoring may be used to prevent iatrogenic injury, NMB at start then remi

Question 80

What are some different ventilation approaches (w pros/cons) for panendoscopy? (ie. jet ventilation catheter)sites)

Answer 80

spont ventilation: challenge= deep enough plane for VC relaxation sans paralysis without apnoea/CV instability- THRIVE useful

microlaryngoscopy tube (good visualisation ant 2/3 larynx but poor access to posterior commissure lesions, there is airway protection, risk airway fire w laser, high airway R w small tube so need higher driving pressures & lower I:E ratio, not good w spont vent)

supraglottic jet ventilation:
-PROS: tubeless field- optimal surg access for post commissure lesions
-CONS/issues:
relies on surgeon maintaining patent airway while concurrently operating & requires good alignment of jet w the airway (otherwise risk gastric distension w entrained air)
issues with VC flutter
airway unprotected, aspiration risk
can’t monitor EtCO2, the safety features of automated HFJV (incl airway pressure & ETCO2 monitoring) aren’t reliable
risk barotrauma (esp v narrow airways, Venturi effect)
risk tumor seeding
require TIVA

subglottic jet ventilation
-PROS: less VC movement & more efficient cf supraglottic (more consistent FiO2 delivered, can monitor airway pressures & FiO2)
-CONS: requires TIVA, greater barotrauma risk than w supraglottic, small (3.4 or 4.3mm ED) but may still hinder surg access as catheter in surgical field

trans-tracheal ventilation:
-Useful for difficult airway (poor laryngoscope access or glottic pathology), provides tubeless field, can control FiO2
-CONS: unable to monitor airway pressure & ETCO2, have incomplete control of ventilation, risks barotrauma (mitigated w use of automated HFJV vs manual), tumor seeding, issues w trans-tracheal catheter (block, kink, dislodgement), contraindicated in tight stenoses, requires TIVA, no airway protection

Question 81

What should the extubation plan be?

Answer 81

DAS guidelines; if “at-risk” of airway obstruction on extubation, consider delayed extubation or planned tracheostomy

otherwise: upright, full reversal of NMBDs, pre-oxygenation prior to extubation
having remifentanil infusion w effect-site target 1-1.5ng/mL assists smooth emergence, obtunds CV responses, reduces agitation & coughing
consider AEC in carefully-selected pts

Question 82

What should the remifentanil Ce target be for smooth extubation?

Answer 82

1-1.5ng/mL

Question 83

What are some considerations for extubation over an AEC?

Answer 83

can be used for emergency reintubation or oxygenation but they get easily kinked or displaced, meticulous care essential to ensure distal tip remains mid-trachea at all times

Question 84

What level is postop pain after head & neck surg?

Answer 84

usually moderate; manage w multimodal incl paracetamol, opiates, consider subcut or S/L if swallowing impaired
Reserve PCA for extensive resections or flap donor areas
Consider local infusions for opioid sparing

Question 85

What analgesic strategies may assist with coughing/irritation from new tracheostomy?

Answer 85

humidified O2, neb 4% lignocaine, judicious opiate use

Question 86

What strategies may reduce PONV after head & neck Ca surg?

Answer 86

regular anti-emetics, liberal IVT, early PO intake

Question 87

What are postop goals for free flap?

Answer 87

regular monitoring
maintain adequate filling, normotension, normothermia
Hct 30-35% (lack of evidence for dextran & aspirin)

Question 88

What’s the general approach to respiratory distress after head & neck surgery?

Answer 88

call for help (ENT surgeons)
sit pt up, high-flow nasal O2 FiO2 100% & nebuliser Adr as temporising measures
gentle nasendoscopy to Ax if fiberoptic intubation faesible
Plan for intubation with “double-airway intervention” setup, with personnel & equipment for emergency surgical airway

Question 89

What is the risk of tracheostomy too high? too low?

Answer 89

if near 1st tracheal ring or cricoid, risk tracheal stenosis. If too low, risk erosion to Tx inlet great vessels.
ideal site btwn 2nd & 3rd tracheal rings.

Question 90

Why should a post-tracheostomy CXR be performed?

Answer 90

exclude pneumothorax

Question 91

What are relative contraindications for perc tracheostomy?

Answer 91

age <12
significant gas exchange problems (eg. PEEP >10cmH2O, FiO2 >60%)
moderate coagulopathy (eg. PT >1.5x ULN, plt <50000x10^9/L)
morbid obesity w short neck
Suspected/confirmed C-spine injury
limited neck movement
aberrant blood vessels
thyroid or tracheal pathology
evidence of infection over insertion site

Question 92

Is there strong evidence for reduced ventilator-associated pneumonia, hospital LoS, ICU days, ABx use or mortality w early vs late tracheostomy in pts w prolonged intubation?

Answer 92

no

Question 93

When should tracheostomy tubes be replaced?

Answer 93

Not within 72hrs (& ideally not within 7 days) if perc trache, allowing a tract to form
If inner tube, should do every 7-14 days initially, decreasing frequency as the stoma becomes better-formed & pulm secretions decrease
If no inner tube, can leave in for up to 30/7

Question 94

What are the risks with the ventilating with cold unfiltered air?

Answer 94

Incr production & viscosity of secretions which can be difficult to clear, cause atelectasis, impair gas exchange, oxygenation & may obstruct the tube
This air also uncomfortable & can cause tracheal mucosal keratinisation

Question 95

What are tracheostomy tube sizes based on?

Answer 95

internal diameter- 5-9mm, of outer tube for single lumen devices & inner tube for double lumen devices

Question 96

What’s the safety advantage of dual cannula tracheostomies? balanced against? When should dual cannula be used

Answer 96

can easily remove the inner tubing if life-threatening obstruction due to blood clots or secretions
balanced against incr WOB & lengthened weaning w smaller internal diameter
Generally use dual lumen for all pts aside from those w specific reasons not to eg. obese or have local tissue swelling & require an adjustable flange or if they require flexible tube due to having anatomy where a rigid tube may cause abrasion or tube obstruction

Question 97

What’s the benefit of cuff on tracheostomy tube?

Answer 97

reduces air leak during PPV, reduces aspiration risk, change to uncuffed tube when no longer need mech vent or if aspiration risk considered low

Question 98

What has higher complication rate- surgical or perc tracheostomy?

Answer 98

surgical

Question 99

What are some immediate complications of tracheostomy?

Answer 99

oxygen desaturation
haemorrhage
aspiration
air embolism
failure of procedure
damage to tracheal rings/other structures (eg. RLN, oesophagus)

Question 100

What are some intermediate complications of tracheostomy?

Answer 100

Delayed haemorrhage (eg. infective erosion into blood vessels)
Tube displacement
surgical emphysema (eg. false passage of tube into pretracheal tissue)
pneumomediastinum (eg. from erosion of the tube into surrounding structures)
pneumothorax
tracheooesophageal fistula
tracheoarterial fistula
dysphagia
infection
tracheal necrosis (eg. at the level of the cuff)

Question 101

What are some delayed complications of tracheostomy?

Answer 101

Tracheal stenosis (eg. at the level of the stoma or the level of the tube due to mucosal necrosis & fibrosis- low-pressure high-volume cuffs have reduced incidence of tracheal stenosis)
decannulation problem (eg. if they have bilateral VC paralysis, fractured cartilage)
tracheo-cutaneous fistula (eg. if granuloma forms or healing is delayed)
disfiguring scar

Question 102

What’s the most common & most commonly fatal complication of tracheostomy?

Answer 102

Bleeding

Question 103

What’s the approach to bleeding tracheostomy pt?

Answer 103

Control airway with conventional intubation, ensuring the cuff of the ETT is below the stoma. Can then proceed to surgical exploration.

Question 104

What should always be used for elective perc tracheostomy?

Answer 104

fiberoptic bronchoscopy, to guide initial withdrawal of tube to glottis & to observe insertion of trache

Question 105

What are some general principles with replacing tracheostomy tubes

Answer 105

avoid multiple attempts which may risk surgical emphysema & swelling which may make laryngoscopy impossible; consider establishing airway from above early vs late

Question 106

What are some logistical considerations which may help when replacing a tracheostomy?

Answer 106

neck extension
going down a size

Question 107

When is a pt ready to be decannulated?

Answer 107

When they don’t require resp support & they have adequate respiratory reserve to cope with the incr deadspace without the tracheostomy tube
when they can adequately swallow, cough & manage their own secretions/protect their own airway
When they can tolerate cuff deflation or capping (w fenestration or cuff deflated)

the tube is removed, stoma covered w semi-permeable dressing
pt encouraged to gently press over the defect when speaking/coughing, monitor pt for signs resp distress

Question 108

What’s a Bloom-Singer valve & what to do if it dislodges?

Answer 108

it’s a one-way valve that allows phonation & prevents saliva & oral secretions from being aspirated into the lungs of pts who’ve had total laryngectomy; it passes via a tracheo-oesophageal puncture (2-3/52 postop, in the interim a foley’s catheter or feeding tube keeps the TOP patent)
If the valve has been removed, call ENT, if remote, place a foley’s catheter w 3mL air into the space while t/f, if aspirated, remove w FOB

Question 109

When should decannulation of a trache be performed? other considerations?

Answer 109

daylight hours w rested patient & staff avail, have equip & expertise for stomal or oral intubation avail

Question 110

Why are tracheostomy tubes generally changed?

Answer 110

for hygiene purposes

Question 111

SS_HN 1.9:
Outline principles of anaesthetic Mx for awake tracheostomy
What’s the framework for planning awake tracheal intubation?

Answer 111

-awake tracheostomy under LA= airway plan if anticipate difficult/impossible BMV or laryngoscopy (significant supraglottic or glottic obstruction) but AFOI not possible (eg. narrowing too small for scope or tube).
Particularly beneficial if AFOI may precipitate total airway obstruction. Awake tracheostomy may be a plan B for AFOI.
standard framework of sedation (eg. dexmed), topicalisation (eg. 2% lignocaine infiltration), oxygenation (NHF or mask/nasal prongs w etcO2 if able to read (or pletysmography)
Performance (have plans a/b/c; if unsuccessful ATI:FONA by most eperienced provider, only option is GA

verbal informed consent & discussion of expectations, established airway strategy with backup plans, cognitive aid/checklist avail, equipment & trained personnel briefed & communicating well
oxygenation
-essential throughout ATI
concurrent HFNC can be beneficial
sedation
-minimal (pt responds to voice, spont vent & no CV compromise), ideally by a separate practitioner
topicalisation
-careful communication, reassurance vital- technique may be limited by pt agitation
-meticulous & tested; max lignocaine 9mg/kg lean BW
performance (position w pt, video monitor & pt monitor in direct line of site, direct access to anaes machine, O2 delivery, suction)

Question 112

Max attempts for AFOI?

Answer 112

3 + 1 by a more experienced operator

Question 113

Max dose of lignocaine for AFOI topicalization?

Answer 113

9mg/kg lean body weight

Question 114

What check should be done prior to induction of anaesthesia?

Answer 114

2-point check (visual confirmation of tube passage & capnography) to confirm correct tracheal tube position

Question 115

According to the awake tracheal intubation guidelines (2020), what’s the rate of combined difficult FMV & intubation? Difficult FMV? Difficult SAD placement or ventilation? Difficult tracheal intubation?

Answer 115

0.3%
1%
2%
2-10%

Question 116

What’s the rate of success of SGA when used for failed endotracheal intubation?

Answer 116

65%

Question 117

Rate of emergency FONA?

Answer 117

1:50,000

Question 118

Rate of death due to airway management?

Answer 118

1:180,000

Question 119

rate of failed awake tracheal intubation?

Answer 119

1% (& rarely requires rescue strategies)

Question 120

What’s the only absolute contraindication to ATI? relative contraindications?

Answer 120

pt refusal
relative= local anaes allergy, airway bleeding, agitation

Question 121

In which pts may ATI:VL be preferable over ATI:FB?

Answer 121

those with airway bleeding

Question 122

What are some tips for tube selection for ATI & positioning?

Answer 122

not standard pvc (Parker tip, reinforced or iLMA tubes provide easier tracheal intubation, easier railroading & decreased laryngeal impingement)
Bevel should be placed posteriorly
smallest ext diameter is advisable (reduce risk of impingement)

Question 123

What are the key components of cognitive aid for ATI?

Answer 123

STOP (sedation, topicalisation, oxygenation & performance/positioning)

Question 124

How should O2 be delivered for ATI?

Answer 124

warmed, humidified high-flow nasal O2 (significantly reduces desaturation to <1.5% vs about 15%)

Question 125

What’s the grade A recommendation for topicalisation during ATI?

Answer 125

Nasal passages should be topicalised with vasoconstrictors before nasal intubation

Question 126

Why is lignocaine the most commonly used topicalisation drug for ATI? At what lignocaine doses are toxic plasma concentrations demonstrated?

Answer 126

Favourable cardiovascular & systemic toxicity profile
6-9.3mg/kg therefore shouldn’t exceed 9mg/kg lean body weight

Question 127

Is cocaine recommended for topicalisation & vasoconstriction?

Answer 127

No, ass’d w toxic CV complications & analgesic efficacy for nasotracheal tube insertion is not better than co-phenylcaine

Question 128

What may be the benefit of higher LA []s for airway topicalisation in AFI?

Answer 128

more rapid onset

Question 129

Are antisialogogues recommended for ATI? dosing timing?

Answer 129

Yes- clarity of visual field may improve, although there’s limited evidence to support their use in ATI
Intramuscular glycopyrrolate 40mins before ATI for peak effect

Question 130

What level of sedation aiming for with ATI? other considerations?

Answer 130

minimal sedation
A drug-induced state in which the patient responds normally to verbal commands, the airway, spontaneous breathing and cardiovascular functions unaffected

ideally delivered by a second operator to help limit risk over-sedation

Question 131

What sedatives are recommended for ATI?

Answer 131

remifentanil or dexmed, propofol higher risk over-sedation, coughing & airway obstruction cf remi

Question 132

What target dose of remi could be used for ATI?

Answer 132

minto TCI 1-3ng/mL

Question 133

How much lignocaine in 1 spray of 10%? 1mL of 2%? 2.5mL cophenylcaine? 1 spray of cophenylcaine?

Answer 133

10mg, 20mg, 125mg, 5mg (it’s 5% lignocaine so 1 spray, 0.1mL, is 5mg lignocaine. it’s 0.5% phenylephrine)

Question 134

are glossopharyngeal or superior laryngeal nerve blocks recommended for AFI?

Answer 134

not except for the very experienced; ass’d with higher plasma [] of LA, LAST & lower pt comfort

Question 135

What’s the onset time & DOA of topical lignocaine?

Answer 135

5 mins, 30-60mins

Question 136

What are some considerations for the approach to AFOI in pt w suspected BOS or facial fractures?

Answer 136

avoid NHFO, oral approach to ATI

Question 137

considerations for obese or pregnant pt requiring AFOI?

Answer 137

consider US the front of neck & mark cricothyroid membrane as anticipate FONA more difficult

Question 138

Consideration for a pt w stridor for AFOI?

Answer 138

avoid or minimise sedation
use lower [] lignocaine or consider nebulised
HFNO recommended
prime for FONA (2-team prep)
use smallest ETT & most experienced practitioner

Question 139

For how long after ATI should a pt remain NBM? why?

Answer 139

2 hrs; although lignocaine analgesic DOA is 40 mins, return of laryngeal reflexes can take longer, terminal elimination half-life lignocaine up to 2 hrs.

Question 140

What’s the incidence of CICO?

Answer 140

0.04%

Question 141

What are some complications of high-pressure source ventilation?

Answer 141

pneumothorax, surgical emphysema, pneumomediastinum, hypoxia, hypercapnia

Question 142

What temporising factors may help stabilise a stridulous pt in an acute emergency presentation?

Answer 142

preop steroids, nebulised adrenaline, beta agonists or anti-sialagogues may help stabilise before securing the airway. HFNO may assist reducing WoB & provide oxygenation.
Heliox may reduce WoB by decr turbulent flow & resistance of upper airway but it’s use in acutely hyperaemic pts is limited by the FiO2 delivered.

Question 143

What are some issues with laryngo-tracheal surgery? what must I know?

Answer 143

shared airway & potential airway compromise pre- intra or post-op
pts often w significant comorbidities
must know the degree, level & type of airway narrowing before commencing, FNE is the most useful dynamic Ax, CT does give static depiction of the airway in supine
Must know the surgical approach (eg. use of lasers) & pt factors which may influence choice of anaes technique.

Question 144

How small does a MLT go down to?

Answer 144

4mm, with normal adult length (31cm, which is equivalent to adult size 7 length))

Question 145

what takes longer? surgical cricothyroidotomy or tracheostomy?

Answer 145

surgical cricothyroidotomy

Question 146

What are 3 approaches to tubeless field anaesthesia?

Answer 146

HPSV, apnoeic oxygenation or spont breathing

Question 147

On screenshot 22/11/21, what are figures A-E?

Answer 147

manujet device, ruvussin cricothyroid cannula, laser flex ETT w double cuff, hunsacker mon-jet, laser jet double-lumen catheters

Question 148

what should be the FiO2 when laser used?

Answer 148

21%

Question 149

Benefits of spont vent? how may O2 be delivered?

Answer 149

maintaining -ve intrathoracic pressure assists w pathologies below larynx eg. tracheal disease or foreign body inhalation, where paralysis may decrease patency of lower airway
allows surgeon to perform dynamic functional assessment of glottis

can deliver O2 nasally or more distally via narrow transglottic catheter

Question 150

Benefits & problems with HFNO?

Answer 150

assists w pre-O2, high-risk intubations & high-risk extubations
avoids risks w jet ventilation & provides superior gas exchange to low-flow techniques
requires airway patency
ETCO2 monitoring unavailable
delivery of high FiO2 for prol periods–> nitrogen washout & rapid alveolar O2 absorption w alveolar collapse & absorption atelectasis

Question 151

SS_HN 1.10: Discuss the precautions, possible complications and implications for anaesthetic management associated with the use of lasers in ear nose and throat surgery
what are some safety strategies for laser airway surgery?

Answer 151

General/institutional:
-excellent teamwork & communication- staff trained & familiar with laser surgery policies
-designated laser safety officer
-safety equipment: eye protection (all staff & patient, colour specific to the laser), signage & door tapes/window coverage, smoke evacuators & masks
-fire drills, extinguishers/firefighting equipment

Airway-specific:
-transglottic catheters
-airway management options:
laser-resistant ETTs- the internal is usually PVC so still flammable but it’ll either have metal links in the tube wall or be covered in metallic foil with an outer non-reflective layer (they resist damage, dissipate high energy of laser, reduce the risk of tube fire & reflection damage to adj tissue)
-the cuffs are high pressure, low-volume, PVC so not laser resistant- dual cuff, distal (inflate first) w saline & proximal (inflate 2nd) dyed with methylene blue, in event that the upper cuff struck by laser beam, or may have sponge cuff for tube security, but these tubes have thick walls hence smaller internal diameters, require higher driving pressures, require a pre-loaded stylet for intubation, should be removed before emergence to avoid discomfort (eg. mallincrodt laser-flex (stainless steel), xomed laser shield II (silicon wrapped in aluminium), trans-glottic (hunsaker mon-jet, LASER SAFE) for JV which has side-port for monitoring CO2 & has an introducer, other options= no tube in airway, venturi jet ventilation (pt needs to be RELAXED & hand on diaphragm to minimise risk of barotrauma- start low & go up until chest wall movement)
-bucket of water
-be able to drop FiO2 to 0.21 while laser active
-water-based lubricants, avoid plastic tape
-consider damp gauze
-flame-resistant drapes
-AVOID N2O

Surgical:
matte finished or ebonized surgical instruments
trained operators
use minimum power, smallest spot size, shortest exposure time for laser

If airway fire:
- stop source (laser)
- stop O2 & flow of all gases to airway, remove ETT & douse with saline
- resume mask vent, initially air (until certain nothing left burning in airway) then switch to O2 enough to maintain SpO2, re-intubate (temporary tracheal jet ventilation if re-intubating impossible)
- maintain anaesthesia IV
- examine airway for debris (& remove) via laryngoscopy & bronchoscopy. lavage & fibreoptic bronchoscopy may be indicated if airway injury. low trache or cricothyroidotomy may be indicated.
- ICU intubated (expect airway oedema); specialised care may be needed early post-burn to maintain gas exchange, ARDS may develop slowly
-IV corticosteroids to limit burn oedema
-CXR, ABG w co=oximetry for smoke inhalation Ax

Question 152

benefits of topicalisation of the airway for tubeless techniques?

Answer 152

supplements GA, lessens response to instrumentation, reduces coughing, enhances analgesia, lessens risk of laryngospasm @ extubation, essential for SV methods

Question 153

what are some high-risk extubation strategies?

Answer 153

remifentanil spont breathing
exchange onto LMA
leave in aintree or other airway rescue device
must have a clear strategy for airway rescue

extubating onto HFNO

Question 154

are MLT tubes laser resistant?

Answer 154

no

Question 155

What are some indications for tracheobronchial stents? most common indication?

Answer 155

intrinsic lesions, extrinsic compression or tracheomalacia
most commonly for palliating respiratory symptoms in pts w malignant lesions

Question 156

Where do the recurrent laryngeal nerves branch?

Answer 156

L) under aortic arch, R) under R) subclavian

Question 157

Are areas of lung that have been collapsed for >3/52 considered recoverable?

Answer 157

No

Question 158

What are some complications from insertion of airway stents?

Answer 158

pneumothorax or pneumomediastinum from airway perforation, airway obstruction from a malpositioned stent or oedema, disseminated pneumonia after relief of an obstruction which may have localised a distal infection

Question 159

What does each 2.5cm above the heart correlate to wrt decrease in arterial blood pressure?

Answer 159

2mmHg

Question 160

What is the maximum dose of phenylephrine (topical) & management of severe HTN w phenylephrine?

Answer 160

0.5mg in adults, 20microg/kg in children (up to 25kg)
direct vasodilator or alpha antagonist= management

Question 161

What are some perioperative complications of FESS?

Answer 161

haemorrhage with airway compromise, dural puncture, CSF leak, meningitis, orbital or optic nerve trauma

Question 162

If a pt has increased WoB & dyspnoea on exertion with known tracheal stenosis, what percentage reduction in luminal diameter is present?

Answer 162

at least 50%

Question 163

What is inspiratory stridor associated with?

Answer 163

at least 50% reduction in diameter of glottis or periglottis

Question 164

What holds more weight in assessing a picture of degree of tracheal obstruction? imaging or Hx & recent bronchoscopy results?

Answer 164

The latter 2

Question 165

To what diameter must a lesion narrow the tracheal lumen before abnormalities are detected on spirometry?

Answer 165

<8mm

Question 166

SS_HN 1.18: What’s a fire risk assessment tool & how does it work?

Answer 166

Silverstein fire risk assessment tool assigns risk points 0-3, based on ignition source & it’s proximity to potential oxidisers & flammable material. above xiphoid=1 point, open oxygen source 1 point, ignition source 1 point (laser, cautery, fiberoptic light source), tracheal procedures= 3 points (highest airway fire risk score)

Question 167

What are some ways to mitigate risk of OT fires?

Answer 167

risk assessment, if high risk agree on team plan & roles for preventing & managing OT fire
limit use of ignition source in proximity to oxidiser-enriched environment (Announce use of ignition source, reduce FiO2 during laser or cautery (reduce the Optiflow FiO2 (with blender) down to <30%, aiming to keep SpO2 >94%, then reduce flow rates as much as possible maintaining SpO2), stop use of nitrous oxide) & configure surgical drapes to minimise accumulation of oxidisers
use laser-resistant ETTs (or laser-resistant JV tubes) & cuffed tubes for airway surgery
allow adequate drying time for flammable skin prep solutions
wet the gauze/sponges in proximity to ignition source

Question 168

What steps are taken if there is an airway fire? then once fire out?

Answer 168

Remove fire components: stop laser/diathermy (ignition source), remove fuel (ETT, remove any gauze/other fuel), cease oxidiser (stop flow of all airway gases (oxygen, N2O))

Extinguish fire: pour saline into airway

once fire out re-establish ventilation (w BMV) but limit oxidiser-enriched environment if clinically appropriate (use lowest []O2 to maintain SpO2).

-maintain anaesthesia with TIVA

-examine ETT for potential damage/retained fragments or airway burns & remove debris- if blowtorch fire likely need bronchoscopy, lavage, flexible (examine) +/- rigid bronch if needing to remove debris

-if damage, reintubate with a large ETT in case of subsequent airway oedema

-consider tracheostomy if signifiant upper airway injury. Assess oropharynx & face.
if burnt tracheobronchial tree, likely V-V ecmo (poor prognosis)

CXR, ICU, ?steroids

Incident reporting, pt open disclosure, psych counselling
hot/cold debrief for staff involved
qA activities as a result

Question 169

what’s an oxidiser-enriched atmosphere?

Answer 169

one where the FiO2 is > room air or if there’s any [] of N2O

Question 170

how long after minimising delivered oxygen should an ignition source be used?

Answer 170

1-3 minutes, if the pt is O2-dependent, reduce the FiO2 to the minimum required to avoid hypoxia

Question 171

if a fire isn’t extinguished on the first attempt, what type of fire extinguisher should be used?

Answer 171

CO2

Question 172

What’s the average tracheal length & diameter in males & females?

Answer 172

11.25cm, external diameter males 2cm (inner diameter 1.5-2.5cm) & 1.5cm (1-2cm)

Question 173

How does tidal volume breathing & coughing or forced exhalation alter tracheal diameter?

Answer 173

inspiration (TV) 10% incr diam, coughing may reduce diameter 30%

Question 174

What’s an option for long ETT (eg. if want to place distal to a distant obstruction or in mainstem bronchus)?

Answer 174

Phycon ETT, or taking a DLT & removing tracheal lumen (requires time & sanding), combining 2x ETTs, larger one used distally, preserve pilot cuff & balloon of distal tube, join them together while wiping connecting surfaces with ETOH to improve bonding

Question 175

what may be used to prevent soiling of unventilated lung during repair tracheooesophageal fistulae?

Answer 175

bronchial blocker

Question 176

What’s a big disadvantage of using VA or VV ECMO for anterior mediastinal mass or unusual/large tracheal lesions?

Answer 176

anticoagulation (partial heparinisation) is required, increasing risk of surgical bleeding

Question 177

in which patients with tracheal masses is an inhalational induction with sevofluorane selected? What contingency should ALWAYS be in place prior to commencing inhalational induction technique?

Answer 177

those for whom adequate oxygenation & ventilation is thought to depend on maintenance of spontaneous -ve pressure breathing so that resp mechanics remain similar to awake state (eg. critical tracheal stenosis, dynamic pathology eg. combined stenosis & malacia or unstable tracheal mass)
surgeon prepared for urgent intervention w rigid bronchoscopy & jet ventilation

Question 178

How much lignocaine per spray of co-phenylcaine? how many sprays per nostril?

Answer 178

5mg
4

Question 179

How long for cophenylcaine to have effect?

Answer 179

5 mins

Question 180

How long give IV glycol to work?

Answer 180

15 mins

Question 181

How many mg of lignocaine per spray of 10%?

Answer 181

10mg

Question 182

How much lignocaine removed by hepatic metabolism if swallowed?

Answer 182

70%

Question 183

How long is the duration of action for atomisation or nebulisation of lignocaine?

Answer 183

10-15 mins, so be organised & have the neb on the pt as wheel in

Question 184

what are some useful endpoints for adequate topicalisation?

Answer 184

voice change, loss of gag reflex

Question 185

Benefits of gargling lignocaine? how much to use?

Answer 185

topicalise oropharynx, suppresses gag, use 4mL of 2% (80mg) lignocaine viscous, gargled for 30 seconds

Question 186

Strategy for topicalising epiglottis/larynx?

Answer 186

MAD 4% (take 4mL of 10% & dilute into 10mL, deliver 6mL)
further 6mL 4% in syringe via working port, under visualisation

Question 187

What does THRIVE stand for?

Answer 187

transnasal humidified rapid-insufflation ventilatory exchange

Question 188

Will a size 5 MLT accommodate an adult stylet? how about a size 4?

Answer 188

Yes, no

Question 189

How should the I:E ratios be adjusted when using a MLT?

Answer 189

shortened, since slower expiration (higher airflow resistance)

Question 190

How long can SpO2 be maintained in a slim, minimally comorbid patient during apnoea O2 with high-flow oxygen?

Answer 190

30-60mins, there’s also some CO2 washout

Question 191

What are some benefits of tubeless anaesthesia?

Answer 191

unimpeded access to the larynx, particularly for posterior glottic lesions
dynamic airway assessment (surgeons can observe the larynx move, distinguishes between fixed & functional obstructive lesions)
avoidance of intubation & the issues with extubating pts (bronchospasm, laryngospasm, coughing blood)
suitable for tight lesions not amenable to intubation
may be suitable for laser surgery where a blender used

Question 192

Describe STRIVE-HI

Answer 192

Propofol only, marsh model, Cp-Ce=1
Start with Cp 2-3, when Ce comes within 1mcg/mL of target Cp, increase Cp by one. Requires patience to avoid apnoeic episodes. Maintain airway support w jaw thrust, from initiation of infusion. Generally LOC occurs at Ce of 2, NPA can be inserted at Ce of 3 (after co-phenylcaine), can do direct laryngoscopy & spray lignocaine to cords at Ce of 5, can do suspension laryngoscopy at Ce of 6-7 (high inter-patient variability for all targets)
Can use low-dose remi (0.02-0.08mcg/kg/min)
At end of case, cease remi & props, LMA inserted for transfer to recovery

Question 193

What drugs & equipment are required for STRIVE-HI technique?

Answer 193

Pre-induction:
Lignocaine <=1mg/kg, metoclopramide 20mg, glycopyrrolate 200microg

Other:
Propofol

Remi 50mcg/mL
Fentanyl 100microg
Roc or sux drawn ready to go
Dexamethasone

4% lignocaine spray via MADGIC device, co-phenylcaine nasal spray for prior to NPA

THRIVE; if using laser, have blender set up. FiO2 100%, begin flow 30L/min, gradually titrate up to 70L/min.
Also if using laser, have NaCl bottle conspicuously on top of anaesthetic machine in event of airway fire

Have OPA, NPA & MLT ready
CMAC
LMA for end of case

Question 194

Position for STRIVE-Hi?

Answer 194

10-20deg reverse trendelenburg

Question 195

What are some ways that RR can be monitored during STRIVE-HI?

Answer 195

ecg impedance variation or by modified capnography (gas sampling line attached to metal cannula connected to suspension laryngoscope or to a Hudson mask or placed in the mouth/nose)
manually

Question 196

once a pt has desaturated on high-flow, what required to do?

Answer 196

recruitment; pt unlikely to improve without it

Question 197

Simple way of titrating remi during suspension laryngoscopy?

Answer 197

start 50microg/mL (2mg in 40mL) at 3mL/hr, gently titrate up aiming for RR of 8 & not exceeding 8mL/hr

Question 198

What to do with remi if surgeons are balloon dilating the trachea/larynx? why?

Answer 198

bolus, 20-40microg, since this helps avoid -ve pressure pulm oedema (targets a RR <8, a short period of apnoea is likely

Question 199

What are issues with the coblator during tubeless ENT surgery?

Answer 199

ablates & coagulates soft tissues, involves the flow of saline into the airway & if set to high flow rates, significant saline will enter the trachea

Question 200

why is STRIVE-Hi unsuitable for many Emerg cases?

Answer 200

aspiration risk

Question 201

for what complications should I have a plan/anticipate when undertaking STRIVE-Hi?

Answer 201

apnoea
airway obstruction despite jaw thrust & NPA
aspiration
desaturation
laryngospasm
bronchospasm
airway fire

Question 202

According to the DAS, what is classed as a “low risk” extubation?

Answer 202

fasted, uncomplicated airway, no general risk factors

Question 203

What are the “general risk factors” for extubation identified by DAS?
What are some “airway risk factors” for extubation identified by DAS?

Answer 203

cardiovascular disease
respiratory disease
neurologic conditions
metabolic disorders
special surgical requirements
special medical conditions

airway risk factors:
known difficult airway
restricted access to airway
airway deterioration during surgery (trauma/oedema/bleeding)
unfasted/obese/OSA/obstetric/other aspiration risk

Question 204

What’s the nerve supply of the nares & anterior 1/3 of nasal septum?

Answer 204

anterior ethmoidal nerve from the nasociliary (which is from V1)

Question 205

What’s the nerve supply to the turbinates & posterior 2/3 of nasal septum?

Answer 205

greater & lesser palatine nerves (from maxillary branch of trigeminal nerve)

Question 206

What’s the nerve supply of the oropharynx? larynx?

Answer 206

-anterior 2/3 tongue from lingual nerve from mandibular division (V3) of trigeminal nerve
-Taste to anterior 2/3 of tongue from facial nerve
-taste & sensory to posterior 1/3 of tongue, vallecula & lingual surface epiglottis is glossopharyngeal nerve (lingual branch).
Tonsillar branch of glossopharyngeal nerve supplies the tonsils
Pharyngeal branch of glossopharyngeal nerve & pharyngeal branch of vagus form a plexus supplying the pharyngeal wall
Base of tongue, laryngeal surface of epiglottis & skin above glottis (including aryepiglottic folds & arytenoids) supplied by the internal branch of superior laryngeal nerve (from vagus)
Motor to cricothyroid is external branch of superior laryngeal nerve
motor to remainder of larynx is recurrent laryngeal nerve
Sensory below glottis is recurrent laryngeal nerve

Question 207

What supplies the larynx?

Answer 207

Base of tongue, laryngeal surface of epiglottis & skin above glottis (including aryepiglottic folds & arytenoids) supplied by the internal branch of superior laryngeal nerve (from vagus)
Motor to cricothyroid is external branch of superior laryngeal nerve
motor to remainder of larynx is recurrent laryngeal nerve
Sensory below glottis is recurrent laryngeal nerve

Question 208

SS_PA 1.70: Discuss the anaesthetic management of children requiring more complex shared airway procedures, for example, cleft lip and palate, laryngoscopy, oesophagoscopy, removal of airway foreign body
What are the issues with managing an inhaled foreign body in paediatrics? (also SS_HN 1.8)
INHALED FB:
OESOPHAGEAL FB:

Answer 208

Acute: more risk: emergency, surgeon scrubbed & ready with rigid bronch ALL set up. 3 s’s: patient Stable, Surgeon ready, Spont vent
*may get hyperinflation & mediastinal shift from one-way ball-valve effect.

chronic: longer procedure (piecemeal), infection, poor lung compliance, may need postop ICU/intubation.

INHALED FOREIGN BODY:

Considerations:
-paediatric (most are <3yo): rapport w child & parent

-where is it? Hx/exam/Ix

-laryngotracheal uncommon but more likely to be life-threatening; stridor, wheeze, salivation (symptoms related to oesophagus), dyspnoea, sometimes voice changes, acute resp distress.

large bronchi: cough, wheeze, haemoptysis, dyspnoea, choking, resp distress, decr breaths sounds +/- fever/cyanosis. R) main bronchus more common (but particularly so in adults)
-is it acute or chronic?

lower airway may have little acute distress after initial choking

Acute upper airway obstruction:

MILD= able to speak or cry, may have hoarseness/intermittent stridor, stertor (high-pitched extra-thoracic), good air entry & WoB
–> allow child to adopt position of their choice, avoid distress
–> nebulised adrenaline temporary relief while awaiting definitive measures
*DON’T sweep mouth or do back blows in children who can speak or cough (may worsen obstruction)

MODERATE= tachypnoea, stridor, prol insp time, moderate WoB, nasal flaring, grunt, paradoxical chest movement, decr air entry

SEVERE to COMPLETE:
slowed RR, or marked tachypnoea, sniffing or tripod position, agitated/drowsy conscious state, severe WoB; rapidly progresses to unconsciousness/cardiorespiratory arrest

IF ineffective cough, UP to 5 back blows. if ineffective, up to 5 chest thrusts.
if no relief,
emergency intubation with RSI after pre-O2, fluid resus 10-20mL/kg if hypotensive, if not arrested consider push dose 1microg/kg Adr, ketamine 0.5-2mg/kg & roc 1.2-1.6mg/kg
PPV may push obstruction lower down

ideally keep pt stable with ABC support until rigid bronchoscopic removal
Consider “holding measures”

most commonly presents w partial airway obstruction (cough followed by tachypnoea & stridor, focal monophonic wheeze or decr air entry.

if chronic, may have associated infection, symptoms eg. dehydration, atelectasis, bronchiectasis, pneumonia (chronic cough/wheeze) with infiltrates that don’t resolve w ABx (sepsis), wheeze

After focused Hx (choking episodes, airway abnormalities/associated conditions, signs sepsis/URTI/LRTI) & physical exam (wheeze (often focal, monophonic), stridor, regional variation in breath sounds), primary Ix:
plain XR: neck (PA & lat, w arms & sh inf & posteriorly), chest
lower airway FBA: hyperinflated lung/lucency distal to obstruction (air trapping, air passes w inspn not expn)
atelectasis if complete obstruction
mediastinal shift away from FB
pneumonia distal to obstruction
late= pulm abscess, bronchiectasis.
films ideally insp & exp (incr sensitivity of radiolucent FB; otherwise radiograph normal in @ least 30%). if pt can’t, L) decubitus may simulate expiratory radiographs (but not routinely perfomred).
only consider CT if asymptomatic & only if that would preclude bronchoscopy, otherwise don’t expose the pt to the radiation if not changing plans.

HOWEVER ALL cases of mod/high suspicion FBA should have tracheobroncheal tree examined w rigid bronch (if Dx or location unclear, flexi bronc first then rigid on stand-by to remove in most cases, rigid also permits airway control, good visualisation, manipulation of th object w wide variety o f forceps, ready Mx of mucosal haemorrhage. removes approx 95% of FBs. rarely, thoracotomy to remove. only @ some centres flexi bronch for Mx of FBA in ADULTS only.

Complications:
pushing FB further down making it hard to remove, dislodgement or fragmentation of it into mainstem bronchus of contralateral lung, may be lethal)
PTx
haemorrhage
resp arrest
inability to remove (may have ABx & corticosteroids to reduce inflammation then try repeat rigid bronch, following repeat plain XRs)
if the FB completely occludes trachea, intubate & ventilation may force it back down

when deciding on ventilation, ask ‘where’s the object’; if upper airway or tracheal/ball-valve obstruction, IPPV IS CONTRAINDICATED (need to prevent stop-valve where no air enters distally–> collapsed lung). LOWER airway foreign bodies, IPPV w m relaxant may be acceptable, since the object will be pushed distally by the bronchoscope until it’s grasped by forceps. can give assisted ventilation via a T-piece or high-freq JV).

-shared airway procedure (access issues)

-spont breathing important (+ve pressure may theoretically worsen obstruction)
-where is the FB (look @ XR) & discuss w surgeons their plan re: how to retrieve it, ventilation options (eg. if tracheobronchial, jet ventilation?).. laryngotracheal incr M&M cf bronchial.

REMOVING INHALED FOREIGN BODY:

-FB FROM NOSE: usually child, aim spont vent (PPV facemask risks pushing FB further); RAE tube or LMA, throat pack, 5-10 mins, supine w head ring.

TRACHEOBRONCHIAL:
Patient: often 1-3yo, may have ass’d signs of infection/cough, wheeze

Procedure:

SHARED AIRWAY
-Stimulating w placement of rigid bronchoscope
-20-60mins (depending on how hard to remove, may be longer if chronic, may be complex)
-pt supine w pad under shoulders

Pathology:
-acute or chronic (if chronic may have associated infection/oedema, MAY BE SEPTIC)
-May present as EMERGENCY ACUTE AIRWAY OBSTRUCTION; lower airway obstruction may occur several days after a Hx of coughing.
-CXR hyperinflation of affected side during expiration but a FB isn’t always visible (incr radiolucency, flattened hemidiaphragm, lung hyperinflation +/- mediastinal shift away from side of FB)

ANAES:
pt deep enough to tolerate bronchoscopy
maintain oxygenation
avoid worsening obstruction

Prepare:
AMPLE Hx
ensure child fasted (unless urgent)
limit anxiety- rapport w child, parent presence if helpful (?midaz or clonidine??)
-Contingency in case of emergency obstruction= rigid bronch (ensure compatibility w attachment for a T-piece)
-LA spray for topicalisation, GLYCO (5microg/kg IM or IV or atropine 20microg/kg IM or 10microg/kg IV @ induction) premed useful to prevent bradycardia & dry secretions, improving surgical view
-all equipment, drugs etc in room ready before child & parent come in (allay anxiety) so can induce immediately
difficult airway trolley
prop/remi (stimulating ++)
-personnel: ENT surgeon ready w rigid bronch, skilled anaes nurse briefed re: plan A/B/C

RESUS:
-IV fluid if septic/dehydrated

IV access:
generally for child <12yo if anxious, place when deep (have IM sux & emergency rigid bronch ready)

Monitoring:
SpO2 probe on for induction, ecg & BP once deep

Equipment: rigid bronch, difficult airway trolley
toocth guard
Transfer: may induce pt on parent’s lap (position of comfort, if safe)

Induction:
-Deep inhalational induction using 100% O2 & sevo (safe familiar approach), IV once obtunded, maintain w prop/remi (so constant anaesthesia vs relying on ventilation/volatile via bronchoscope
-alternative= IV induction with fentanyl 0.5mcg/kg followed by incremental props boluses (1mg/kg then increments of <=0.5mg/kg) until child loses consciousness. Or could start with IV dexmed 1mcg/kg.

Maintenance:

*Maintaining patent airway, avoiding airway obstruction- key goal usually to maintain spont vent (theoretically +ve pressure may push the FB further into airway) although little evidence to support this

-During initial maintenance, DEEPEN enough to tolerate bronchoscopy (cough/buck on rigid bronch risks trauma, bronchial/tracheal perf): topical LA (apply up to 4mg/kg lignocaine (concentrated >1%), use direct laryngoscopy, at and through the VCs with MAD. If pt coughs, t2oxygenate until spont vent again- then apply more- if they continue to cough they’re not deep enough. After topicalised, wait a few more mins- proceed slowly as if the pt too deep, they’ll often stop breathing.
Consider a SGA at this point to assist airway patency.
Titrate opiate to ventilatory frequency; rule of thumb= half the pre-op resp rate.
Titrate volatile to resp pattern, muscle tone & HR- maintaining spont vent.
Generally props 250microg/kg/min & remi 0.2mcg/kg/min. give dex to prevent airway swelling.
if JV, start at LOWEST pressure, hand on diaphragm to ensure not over-expanding lungs

switch to propofol TIVA w remi, so not relying on bronchoscope to keep pt deep enough (alternative is volatile insufflated through ventilating bronchoscope but relies on shared airway to administer anaesthesia & may expose OT team to WAGs)

*Maintaining oxygenation; high risk of hypoxaemia during “shared airway”
-can connect a breathing circuit to the standard 22mm connector of the ventilating bronchoscope (for FB in trachea or bronchi)
-if surgeon working at level of larynx (eg. with Parson’s laryngoscope), can attach O2 tubing to surgical laryngoscope or insufflate O2 through a TT passed through the nares into nasopharynx above VCs.
-THRIVE is an alternative.

-reliable capnography won’t be possible; generally will have adequate ventilation & oxygenation if:
a) administering oxygen
b) can see or confirm with surgeon that the airway is open
c) you can see the pt making reasonable respiratory effort (can use plethysmography)

*Communication vital throughout- control the room, own the airway until pt ready for surgeon to take over (maintain spont breathing airway w facemask or LMA until bronchoscopy) continual communication with ENT throughout esp if hypoxia.

allow surgeon intermittent access, ensure oxygenating & anaesthesia deep enough

Removing the FB from larynx is a particularly stimulating time- consider a bolus of propofol at that time to ensure adequately deep.

Emergence:

prevention & management of postop airway problems
-consider SAD or even tube (if significant swelling/trauma/ongoing obstruction) following FB removal.
-generally prolonged PACU stay & review of child before discharge to ward. if post-op croup in PACU, nebulised racemic adrenaline 1-5mg given & ENT consulted- rarely pt may require intubation.
-if traumatic bronchoscopy, dexamethasone 0.25mg/kg IV then 2 doses 8-hourly 0.125mg/kg
-consider chest physio, ABx & bronchodilators as needed
-Rarely pt may need ICU transfer before extubation if airway swelling.

OESOPHAGEAL FB:

focus= identify & treat cases @ risk of complications; depends on location & type of FB
Urgent removal indicated if:
-oesophageal button battery: remove within 2 hrs, STRAIGHT to theatre (don’t delay for fasting), honey for chn >1yo w oes button battery who present within 12hrs of injestion to reduce risk caustic damage while awaiting theatre (don’t await honey prior to theatre transfer!); 10mL every 10 mins, max 6 doses. child otherwise NBM.
-airway compromise
-near-complete oes obstruction (drooling, can’t swallow)
-if sharp, long >5cm or superabsorbent polymer (risks obstruction, may expand 30-60x sie) in oesophagus or stomach
-high-powered magnet (risk GI perf)
-button battery in oes (in some cases, stomach)
-if S&S suggest inflammation or intestinal obstruction (fever, abdo pain, vomiting)
-objects lodged in esophagus for >24hrs or for an unknown duration

PATIENT:
-most age 6/12-3yrs
-most witnessed, asymptomatic, may present w -drooling, dysphagia or refusal to eat, resp symptoms, may localise sensation of something stuck
-perforation from sharp objects may–> neck swell, crepitus, pneumomediastinum.
-longstanding may–> weight loss or recurrent aspiration pneumonia, may erode oesophageal wall, fistula (eg. to aorta!)

PATHOLOGY:
most ingested FBs pass spont but impaction, erosion or airway compromise= serious harm/death
-most likely to lodge @ areas of physiologic narrowing (cricopharyngeus muscle (UOS), aortic arch, Los) or in pts w oes anomalies, strictures, oesophagitis (esp. eosinophilic), prev surgery
common objects:
coins
button batteries (distinguish vs coins w halo lucency (dougle-ring, due to bilaminar structure), bilevel contour (step-off on lateral view (which is on the -ve side, damage more severe in tissue adj to -ve pole), @ separation btwn anode & cathode), coin has sharp crisp edge); battery in oesophagus MUST be removed asap: oesophageal burn, perf, fistula, injury from direct pressure necrosis & if contact wall w both poles of battery–> electricity conduction, liquefaction necrosis & perf.
sharp objects (if lodge in hypopharynx may cause retropharyngeal abscess). toothpicks & bones likely to peforate.
food impaction (esp if underlying pathology eg. eosinophilic oesophagitis, strictures, achalasia, web/ring, dysmotility)
high-powered magnets a source of serious morbidity

Evaluate:
ABC
Hx: refusal to eat, dysphagia/odynophagia, retrosternal pain/grunt, cough/choke, cyanotic episode, stridor/wheeze, vomit/regurg, unexplained GI bleed
size: if >2cm unlikely to pass through pylorus or ileocaecal valve
neck swelling/erythema/crepitus suggests oesophageal perf

Exam:
insp stridor or exp wheeze suggest lodged oesophageal FB w tracheal compression
evidence SBO or perf
signs acute lead toxicity incl vomiting, lethargy within 90mins

Initial Dx test:
biplane (AP & lateral) of neck, chest & abdo.
flat objects in oesophagus usually orient in coronal plane (circular on AP projection); objets in trachea orient in sagittal plane, best seen lateral.

If pt symptomatic but not needing urgent OT or if the FB has dangerous characteristics (>2cm wide, >5cm long, sharp) or if not known, CT w 3D recon or MRI (CI for any metallic FB!)

Procedure:
Flexible endoscopy usually preferred; can directly visualise & manipulate the FB & inspect the GI tract.
GA w ETT (likely RSI)

rigid endoscopy useful for impacted sharp objects @ proximal oesophagus, @ the level of the hypopharynx & cricopharyngeus muscle. requires skill, risks oes abrasion & perf.

magill forceps: for FBs in oropharynx @ or above cricopharyngeus.
would still intubate, even if can easily see it, to protect the airway. use laryngoscope to gently open oesophagus & visualise the FB.

Question 209

Why are button batteries so dangerous if impacted in oesophagus?

Answer 209

Main predictor of clinical outcome is size- larger more likely to be lodged in oesophagus. Lithium batteries deliver higher energy, more likely to promote severe alkaline caustic reaction at tissue level.
Thin design & large surface area–> low resistance circuit with high current flow driven by the power of the battery. with in minutes, electrolysis generates OH @ the -ve pole of the battery, increasing tissue pH. alkaline caustic reaction causes oesophageal tissue liquefaction necrosis. clinically significant tissue damage can occur within 2hr of battery impaction (so prompt removal is indicated when battery in oesophagus)..
perforation into mediastinum (may–> PTx, pneumomediastinum, mediastinitis)/trachea/vascular structures may result- usually perf >12-24hr (only 2% of the time before 24hrs).
Oesophageal damage may continue even after battery removal due to persistently high pH at site of battery impaction.
May–> long-term scarring/stricture formation

Question 210

Why may honey and sucralfate be effective at neutralising pH at the site of an ingested button battery?

Answer 210

viscous, so coat the battery, limiting contact with the mucosa
they are acidic, so effectively neutralise the pH at the battery site
likely to be acceptable to small children (vs lemon juice or OJ)

Question 211

What are some comorbidities that pts presenting for rhinological surgery (eg. FESS, polypectomy) may have?

Answer 211

OSA
Asthma
CF

Question 212

SS_HN 1.7: What are the main anaesthetic considerations for rhino logical surgery?

Answer 212

septo-rhinoplasty= cosmetic alteration/recon of nose (bone/cartilage graft). moderate pain, small blood loss (unless significant delay following a fracture). 60-90mins, head-up tilt & head ring. RAE or oral RAE. throat pack, mod hypoT useful. pt may have obstructive airway disease w nasal polyps, may have ass’d asthma, samter triad (nasal polyps, aspirin allergy, asthma)CF, OSA. may need guedel for FMV.

PRE:
-Consider that usually day case, except if high risk serious bleeding (eg. septoplasty, turbinectomy need IVC over night) or other post-op complications, children with OSA- pt suitability, location/staffing suitability.
-Airway assessment (consider that BMV may be limited by nasal polyps/obstruction, may need oropharyngeal airway)
-Frequent pulmonary comorbidities (COPD, asthma, bronchiectasis, OSA)
-careful consideration for pts with Hx cerebrovascular/coronary artery disease for procedures where hypotensive anaesthesia & topical vasoconstrictors considered (cocaine, phenylephrine)
-usual BP if chronic HTN
-Drug history: 10-20% of asthma pts may have resp symptoms after taking aspirin (association with these pts & chronic sinus inflammation/nasal polyps).
-MAOIs may interact with topical vasoconstrictors.
-Antiplatelet drugs usually withhold before surgery. antihypertensive generally continued but may be harder to control post-induction hypoT

INTRA:
?eyes uncovered (?for polypectomy, surgeon check for eye movement given proximity to ON)

Process for throat packs (airway obstruction from throat pack retention= a “never event”)- risk by human factors such as staff change, unexpectedly rapid recovery & extubation before throat pack removed. Throat packs ass’d with incr incidence of sore throat, dental or soft tissue damage with insertion & they don’t reduce PONV.
As per the 2018 consensus statement co-authored by the DAS, Anaesthestis are not recommended to routinely place throat packs. If a throat pack is required, it should be carefully discussed (pros/cons) during team huddle. It should be inserted by the surgeon (or anaes to help w laryngoscopy if needed or if it’s outside the surgical field), using gauze with a radiopaque thread ensuring it’s part of the swab count- WHO safer surgery checklist should reference the throat pack & a “step back before you pack” pause considered before insertion. In addition, there should be at least one visual check: part of pack hanging out, attached to airway device, mark on the pt, anaes machine (eg. APL valve) & whiteboard- and one written reminder (eg. record insertion & removal on swab count board). Anaes responsible for checking clear airway before extubation, while do south & north suction).

PRIMARY goal= assisting haemostasis (optimises surgical field, limits operating time & risk complications (eg. blood loss, anaemia, aspiration, PONV) or need for nasal packing)

Non-pharmacological:

-reverse trendelenburg 15 degrees

-limited PEEP (limit venous pressure- up to 5mmHg doesn’t affect surgical field)

-avoiding hypercapnia intuitive but not proven in RCTs to limit surgical blood loss

Pharmacological:

-topical vasoconstrictors and LA: routinely used to reduce bleeding in nasal surgery. spray, gel or soaked swabs. cocaine max topical dose 2mg/kg. Moffat’s solution (cocaine, Adr, sodibic) rarely used- concern re: systemic toxicity (HTN, arrhythias, euphoria). phenylephrine more commonly used, as is Adr -sontainng LA. systemic absorption= sympathomimetic.
block the anterior ethmoidal nerve with endonasal infiltration of middle turbinate with LA. Can block the infraorbital nerve trans orally or trans nasally as it emerges through the infraorbital foramen. Can inject into the pterygopalatine fossa via the greater palatine canal with LA & Adr, inducing vasoconstriction of sphenopalatine artery, optimising surgical field & producing analgesia in V2 distribution. Cocaine= both an ester LA & also a vasoconstrictor (blocking NAdr re-uptake at peripheral nerve endings)- BUT it causes more CV side effects (tachycardia, arrhythmias, sustained HTN, MI, acute angle closure glaucoma). Adr is as effective as cocaine & with fewer adverse effects. Phenylephrine is as effective & has fewer reported adverse events vs cocaine & Adr. Oxymetazoline (also alpha agonist) has a strong safety profile (eg. for children or those @ high risk CV complications). Topical agents require 15-30 mins for full effect.

-Corticosteroids (reduce bleeding, operative time, post-op pain, improve surgical field)

-TxA: shown to reduce intra-op & post-op blood loss, improve surgical field in nasal & sinus surgery, has excellent safety profile. Topical application may reduce bleeding & improve surgical field during FESS.

remi benefits for rhinological surgery: controlled hypotension & brady reduces bleeding, facilitates IPPV sans relaxant (& useful for procedures requiring nerve monitoring), attenuates hypertensive response.
issues= brady/hypoT esp in elderly, rebound HTN (can reduce rate right down & give longer-acting opioid 15-20mins before end of OT).

-controlled hypotension: MAP 50-65mmHg, or 30% reduction in baseline MAP. Balance vs risks of organ hypoperfusion, ie. unsafe & high risk if IHD, carotid atherosclerosis, cerebrovascular disease, chronic HTN, autonomic neuropathy, CKD. Discuss BP goals during preop team brief. Achieve via reductions in SVR & CO (HR x SV)- HR of 60bpm is optimal for diastolic filling, improving venous return. Remifentanil useful (reduces HR & MAP, rapidly titratable, dampens haemodynamic responses to surgery, fast postop recovery). Dexmed and clonidine cause hypotension without substantial tissue vasodilation, reduce bleeding & improve surgical visualisation- also have analgesic & MAC-sparing properties. Post-op sedation limits their usefulness.
Propofol TIVA useful as causes vasodilation by depressing central SNS tone (different to inhalational agents which cause non-selective VD of peripheral & cerebral blood vessels). Haemodynamically stable & titratable. Drawbacks of propofol= difficult positioning BIS, must be deep until surgery completed & emergence from propofol infusion may be delayed (problem for day surgery). Meta-analysis of RCTs has shown that TIVA is beneficial in optimising surgical field (improved visualisation) & reducing blood loss cf inhalational.

-adequate analgesia (limit SNS surge)- remi

-immobile surgical field- m relaxant

-protected airway

Shared airway surgery, tube may be obscured under drapes @ opposite end of OT table. must be well-secured. SGA= standard for most day-case rhinology procedures (reinforced, flexible LMA has advantage of a large cuff to protect the airway from blood & secretions. There’s minimal SNS stimulation on insertion & removal, further lessening bleeding HOWEVER it restricts access to surgical field for many oral procedures & is more prone to displacement.. If ETT for pt or surgical factors, south-facing RAE or reinforced tracheal tube (I use south-facing RAE in my practice- reassurance of secured airway in shared airway, multiple surgeons))

-dry airway before emergence: suction under direct visualisation (avoid “coroner’s clot” in nasopharynx behind soft palate) with laryngoscope while still deep, remove any throat packs

-smooth coughless extubation- remi, lignocaine

-risk laryngospasm (esp from recent instrumentation of larynx or irritation by blood). I tend to extubate awake; either deep (FiO2 100%, suction, guedel, turn L) lat/head down (tonsil position), once regular resp, extubate, ensure airway & resp’n intact, keep in tonsil position until airway reflexes return, need skilled recovery staff & me immediately available), or awake (once airway reflexes returned, opioids help limit coughing) not between (particularly paeds).

-anti-emesis

-head-up during recovery limits bleeding.

-postop pain usually not significant; paracetamol, NSAIDs if not CI, rarely require opioid.

regular anti-emetics first 24-48hrs

for polypectomy or esptoplasty or FESS, pt may have postop nasal pack, may incorporate NPA into pack to assist comfort.
sit pt up as soon as awake to limit bleeding. IVC in overnight (may bleed posotp)

Question 213

Where should nasotracheal tubes, temperature probes & NG tubes etc be inserted?

Answer 213

floor of nasal cavity, below inferior concha

Question 214

what’s the blood supply of nose?

Answer 214

ant & post ethmoidal arteries branching from the internal carotid, supply upper part of nose
branches of maxillary (sphenopalatine & greater palatine) & facial (superior labial) arteries supply lower nose

Question 215

what’s Little’s area?

Answer 215

most vascular part of the nose, anterior inferior part of the septum, where the arterial supply of the nose anastomoses. Most common site of epistaxis (only 10% are posterior, from sphenopalatine artery)

Question 216

By what point is inspired air warmed to body temperature & 100% humidity?

Answer 216

nasopharynx

Question 217

damage to which bone may cause anosmia & provide route of infection to CNS?

Answer 217

cribriform plate of ethmoid bone

Question 218

what forms roof of nasal cavity? septum? lateral walls? floor? where’s the Eustachian tube?

Answer 218

nasal & frontal bones
septum by vomer & ethmoid superiorly, cartilage inferiorly
lateral walls- ethmoid, maxilla, palatine bones
floor= maxilla & palatine bone
Eustachian tube, connecting nose to middle ear, is situated posteriorly below inferior concha

Question 219

what forms roof of nasal cavity? septum? lateral walls? floor? where’s the Eustachian tube? Where does the sphenoid sinus & ethmoid, max & frontal sinuses drain?

Answer 219

nasal & frontal bones
septum by vomer & ethmoid superiorly, cartilage inferiorly
lateral walls- ethmoid, maxilla, palatine bones
floor= maxilla & palatine bone
Eustachian tube, connecting nose to middle ear, is situated posteriorly below inferior concha

sphenoid drains post to sup concha. other 3 drain inf to middle concha

Question 220

Nerve supply to the nose?

Answer 220

Olfaction from CN1 to olfactory bulb

V1 branches to nasociliary nerve- gives off anterior ethmoidal nerve, innervating upper septum, nasal tip & ant lat walls along with ethmoid, sphenoid & frontal sinuses.

V2 traverses to pterygopalatine fossa, forming pterygopalatine ganglion, greater & lesser palatine nerves innervate septum, lateral walls of the nose. terminal branch of maxillary is the infraorbital, supplies maxillary sinus, skin lateral to & beneath nose.

Postganglionic PSNS fibres (from facial nerve) travel with maxillary nerve & facilitate secretomotor functions of nasal & sinus mucosa

Question 221

max dose topical lignocaine? cocaine?

Answer 221

9mg/kg

1.5mg/kg

Question 222

What features of history give clues re: airway obstruction? what signs may a pt present with if acute respiratory obstruction?

Answer 222

noisy breathing
voice change
dysphagia
dyspnoea at rest or on exertion
difficulty lying flat/postural symptoms

pts may adapt to chronic obstruction w resp m conditioning to help generate -ve Pit & may have free symptoms but may be close to a “tipping point”
hypoxia
tachypnoea
agitation
increased work of breathing (accessory muscle use)
tracheal tug, chest wall recession
added noise depicts level of obstruction (oropharynx= snoring/gurgling with visible swelling (eg. tumor, angioedema, abscess), dysphagia/drooling/stridor= base of tongue/epiglottis (eg. epiglottis, tumour, angioedema), stridor, PND, voice changes= glottis (eg. rink’s oedema, SGS, tumor), exp stridor= tracheal (intrathoracic, eg, retrosternal goitre)

Question 223

What are the thought processes for managing an obstructed airway?

Answer 223

How time critical is airway management (ie. if airway needs to be secured, how much time?)

How useful will holding measures be?

Where is the lesion? is it mobile? how does it influence airway intervention? (investigations may help if time)

How to best provide airway security for the pt safely: ideally in OT if possible (NAP4):
-am I in the most appropriate location, with the most appropriate personnel & equipment present?
-given my skill set & pathology, which technique is most appropriate?

-clear discussion & communication of primary plan & B & C- WRITTEN ON BOARD, TEAM EMPOWERED TO PROMPT PROGRESSION THROUGH THE STRATEGY.

Question 224

Example “holding measures” for airway obstruction?

Answer 224

-High-flow nasal oxygen: improves airway patency with low-level +ve pressure, improves oxygenation & WOB (hence pt distress- useful for WOB even if pt not hypoxic)- useful as adjunct during awake techniques, prolonging apnoea time if GA induced, provided airway potency is maintained.
-steroids: more useful if elective & time where inflammation or oedema associated with the obstruction- unlikely to cause harm & may be beneficial while little specific evidence.
-nebulised epinephrine: reduces stridor, in adults dose 1-5mg 1:1000 in oxygen
-heliox less dense improves airflow (less likely turbulent flow, lower resistance to flow)- limited data & utility limited by the reduced O2 content of any mixture required to optimise flow characteristics
-may be a useful adjunct during airway obstruction & to Rx any post-obstructive pulmonary oedema; splints any collapsible segment however HFNO may be better tolerated

Question 225

Example investigations for the obstructed airway?

Answer 225

Nasendoscopy- rapid, great deal of info re: dynamic changes in the pts airway (* may not get the same view on laryngoscopy, we don’t know how the airway will behave under anaesthesia)- useful eg. if see a “ball-valve” lesion, want to avoid PPV
CT: rapid & accurate, reasonably & well-tolerated (can be performed with pt lateral if required) however it’s static & posture may influence appearance
MRI: useful for delineating soft tissue & physical structure of the airway but take time to perform & pt must lie flat.

Question 226

When may AFOI be useful for airway obstruction?

Answer 226

skilled operator& assistance
lesion amenable to navigation by the fibrescope & tube passage sans significant trauma
Cooperative patient

If BMV predicted to be challenging (eg. supraglottic obstructing lesions or masses at base of tongue/epiglottis) or inadequate jaw opening.
In the case of glottic pathology, endoscopic assessment must have deemed that the fibrescope & tube will be passed safely with minimal “cork in bottle” effect- AFOI is inappropriate for a stenotic glottis (may be difficult to topicalise, endoscope & tube-related trauma may provoke bleeding)

Question 227

What are some approaches to securing the obstructed airway?

Answer 227

-AFOI
-awake videolaryngoscopy- hyperangulated blade minimises pt discomfort- useful for laryngeal pathology (overcomes “cork in bottle” phenomenon with AFOI (except for brief moment before tube stylet removed- warn pt about this), passage of tube under direct vision= less risk trauma & trube impingement) but less suitable for base of tongue or epiglottic lesions- AFOI (nasal approach) or awake intubation using optical stylets (eg. bonfils) more appropriate for these
-awake tracheostomy- useful if significant supraglottic or glottic obstruction & concurrent HFNC can be beneficial- may be limited by pt agitation

GA with induction may be the only option for agitated pts however rescue techniques must be agreed (eg. ENT scrubbed for FONA, rigid bronchoscopy available, SGA available. any plan involving waking the pt needs to consider if this is viable- SHOULD WRITE PLANS ON THE BOARD & HAVE STAFF FEELING EMPOWERED TO PROMPT PROGRESSION THROUGH THE AIRWAY-MANAGEMENT STRATEGY);
-IV spont breathing technique: benefit of maintaining spont breathing, separation of anaes & O2 delivery assists with issue of relying on airway patency for adequate depth, however require airway patency for THRIVE. useful for tubeless anaesthesia.
- for IV induction with muscle relaxant, NMBAs may improve ventilation in stridulous pts with glottic pathology. HFNC during pre-oxygenation may help prolong apnoea time. Should limit instrumentation; primary plan for success (videolaryngoscope), any failed attempts trigger transition to next stage of management.
-inhalational induction: benefit of maintaining spont ventilation hence reversibility- may keep option of waking the pt available however the airway may be partially obstructed before pt deep enough for airway instrumentation, creating a risk of significant negative Pit & deterioration during this process (not possible to reverse if can’t expire the volatile). CPAP may help splint the airway. Airway patency is VITAL.

Rigid bronchoscopy with high-pressure O2 source may be the primary plan in obstruction of lower airway caused by tracheobroncial lesions.

Final rescue: surgeon ready either scrubbed for FONA (surgical cricothyroidotomy- rescue tracheostomy takes too long) or with a rigid bronchoscope & high-pressure O2 source

Question 228

Problem with sugammadex in CICO?

Answer 228

it’s not in algorithms. only reverses the NMBA part, not the effect of hypnotic drugs- it may be associated with laryngospasm & worsening of airway patency.

Question 229

What would be the rescue strategy for a large retrosternal goitre?

Answer 229

rigid bronchoscope

Question 230

What do a weak voice & poor cough suggest?

Answer 230

laryngeal compromise

Question 231

What must I load onto the tube when using a hyperangulated blade?

Answer 231

stylet, matching the curve of the blade

Question 232

What do we expect to see with maxillofacial trauma (ie. involving mandibular/maxillary structures or the mid-face region)?

Answer 232

copious bleeding (may threaten the airway via aspiration & hypoxia- pt often sitting erect, spitting out blood to limit risk aspiration/asphyxia)

difficult pre-oxygenation

rarely a true issue with trismus unless impacted condyles

if bilateral mandibular fractures the tongue may migrate posteriorly, obstructing the airway

mid-face fractures are associated with airway disruption along the nasopharynx and with C-spine injuries

Question 233

What should we be suspicious of when a pt presents with blunt chest trauma?

Answer 233

tracheobronchial injuries (these have low survival-to-hospital)
fractured larynx
airway oedema

Question 234

What may be the presentation of pts with blunt neck trauma?

Answer 234

cough, dyspnoea, aphonia, stridor, subcutaneous emphysema or haemoptysis; symptoms don’t correlate well with injury location or severity.

Question 235

What are the categories of traumatic airway injuries?

Answer 235

maxillofacial trauma
blunt neck trauma
penetrating injuries
airway burns

Question 236

What are the goals of airway management in TAI?

Answer 236

identify which pts need their airway secured
place a cuffed tracheal tube into the lumen of the airway distal to the location of the injury while avoiding hypoxia
avoid exacerbating a potential or actual airway disruption or migrating the ETT outside the airway
avoid creating or exacerbating subcut emphysema

Ask myself:
-where and when should the airway be managed (consider the facility, distance to OT)?
-who should be involved (for airway management in TAI, the most senior anaesthetic help along with a surgeon with tracheostomy/cricothyroidotomy skills, should be present)?
-how should the airway be managed? (consider aspiration risk, compliance)
-what’s the plan if that plan fails?

Question 237

What are some absolute indications for a pt being in the “crack on” category? (ie. pts in extremis, risks of delaying airway management outweigh advantages of waiting for other personnel or equipment) and conditional indications?

Answer 237

severe hypoxia
airway obstruction from blood or secretions
decreased conscious state
profound shock
cardiac arrest

indications for immediate airway management when associated with actual or expected deterioration (consider both their presenting signs & symptoms + the rate of progression of their underlying pathology):
stridor
respiratory distress
subcutaneous emphysema
expanding neck haematoma
inability to lie flat

Question 238

What’s the “stay & play” triage category for traumatic airway injury?

Answer 238

risk of transferring pt outweighs benefits inferred by being in OT, however they are stable enough to permit delaying definitive airway management in order to gather personnel/equipment/resources and undertake limited investigations (eg. nasendoscopy, XR, US of neck) to maximise likelihood of success.

such pts include those with stridor, dyspnoea, subcut emphysema, neck swelling or intolerance of supine. Pts with multi trauma & major haemorrhage or head injury are other egs. Smoke inhalation in burns pts is another case where the airway may appear stable but underlying oedema is likely to progress & relocating to OT may not be safe (consider distance to OT, staff availability, what equipment is in ED). Signs & symptoms of TAI have poor predictive value so the pathophysiology or mechanism of the injury & consideration of pt factors needs to be considered in influencing decision to “stay & play”.

Senior Anaesthetist & ENT surgeon should be present & consider a capable Anaesthetic nurse.

“holding measures” should be carefully considered (eg. HFNO, CPAP, heliox) due to risk of exacerbating surgical emphysema.

Question 239

What should occur for pts in the “head for home” triage category of TAI?

Answer 239

comprehensive airway assessment including nasendoscopy, radiographs, consideration of neck US and a CT should be considered.

Decision to surgically explore or repair a TAI secondary to blunt laryngeal trauma is based on criteria from the Schafer classification system; combo of presenting S&S, nasendoscopy findings & CT scan. All symptomatic pts with severe oedema, significant mucosal disruption, vocal cord immobility or displaced laryngeal fractures require surgical intervention.

All team members should be in OT at the outset of airway management & roles should be allocated including a “hands-off” team leader.

Question 240

What are the 3 broad categories of airway management technique?

Answer 240

Awake- pt remains in the green zone (*only tenable if pt cooperative)- FOI, VL or FONA
S/V- pt remains in the green zone
RSI- secure airway asleep & apnoeic- pt enters into the vortex

Question 241

What’s a potential primary plan for pts in the “crack on” triage category?

Answer 241

unlikely time for an awake technique- modified RSI +/- MILS- given blind ETT passage can exacerbate airway disruptions or cause ETT to migrate out of trachea, could apply a modified RSI with 2 operators & concurrent videolaryngoscope & flexible bronch:
operator 1 passes ETT to Introits of trachea, at the vocal cords
operator 2 poised with the FB, advances it into trachea, identifying & passing beyond any disruption
operator 1 rotates ETT so leading edge of bevel is furthest from the tear, gently advance it to a depth where cuff well beyond any tear.

If no bronch, smaller than usual ETT, RSI with VL but no cricoid in presence of laryngeal injury/airway disruption & avoid PPV with BMV, SGA or HFNO (just use standard nasal prongs 10-15L/min).

DOUBLE SET-UP: There should always be 2nd clinician with equipment ready & poised to perform emergency FONA (the only viable contingency plan- sometimes the primary plan)

Question 242

What are potential airway plans for a “stay & play” pt with severe maxillofacial injury or penetrating injury to pharynx or hypo pharynx?

Answer 242

blood is biggest issue; subglottic structures likely intact.

Awake VL or awake surgical airway primary plan options with highest success, if combative/uncooperative, SV (FB/VL/FONA) vs RSI (VL +/- FB-assisted) depends on risk of aspiration & ability of pt to maintain a patent airway while anaesthetised- ketamine may be used to gain control of combative pts prior to RSI.

Question 243

What’s a potential problem with rigid laryngoscopy or bronchoscopy if TAI pts?

Answer 243

C spine injury a contraindication

Question 244

Useful question to ask for TAIs?

Answer 244

what’s the airway plan if primary plan fails?
what’s the plan if the airway is lost now?

Question 245

What’s the incidence of CICO?

Answer 245

1: 10 000 to 1: 50 000 routine GAs, may be higher outside the OT
This is much lower than the incidence of difficult intubation so we must be good @ preventing or successfully managing evolving airway obstruction

Question 246

What is CICO?

Answer 246

Failure to oxygenate due to upper airway obstruction (at or above the immediate subglottic region) which persists despite all reasonable airway manoeuvres @ or above this level hence decision to bypass the obstruction & access trachea in infraglottic region across anterior neck

Question 247

What’s “transition” in a CICO situation?

Answer 247

Phase of care leading up to & including the declaration of CICO. If airway obstruction occurs, attempt one or all supraglottic rescue pathways.

Question 248

What are the 3 supraglottic rescue pathways, strategies to optimise & what is the level of SpO2 @ which concern escalated?

Answer 248

1. BMV (position, 2 hand 2 operator, ensure no foreign body (eg. suction), ensure adequate DEPTH +/- muscle relaxation, guedel/NPA, remove foreign body, clear moisturiser etc from perioral area)
   
   2. SGA (UP TO ?3 attempts (2 in obs, PS 61 says 2) w different sizes or types)
   3. ET intubation (up to 3 optimised intubation attempts varying type & size of laryngoscope, considering hyper-angulated, consider bronchoscope-guided intubation, use external laryngeal manipulation, use adjuvants (stylet or bougie)- may have less if it appears further attempts would be counterproductive to supraglottic rescue via BMV or SGA)

Attempts @ each pathway should include optimising position, suction/incr O2 flow/delivery (Maintain constant 100% FiO2), adjuncts, size/type, considering muscle relaxation, assistance

Escalate concern if SaO2<90%

Question 249

What are some of the human factors that have a key role in the prevention & management of CICO?

Answer 249

Organisational factors:
-regular training matched to cognitive aids, standardised practices & equipment
-safety programs aimed at risk reduction, early identification, rectification of errors & rapid recovery from adverse events (airway registries, early warning systems, multi-D care of at-risk pts, robust use of checklists, adherence to best practice guidelines, QA data collection, reporting of adverse events, promotion of a culture of safety emphasising teamwork & open assertive communication)

Cognitive factors:
-cognitive errors increase in emergency due to task loading & sensory overload. Minimise by:
-Use of cognitive aids (simplified content & symbols- have them available to the whole team)
-Self-awareness & self-monitoring (eg. deep breath, manage stress & fatigue, identify unproductive cognitive processes & high task workload that reduce cognitive resources & lead to errors)
-encouraging team members to provide input or raise concerns
-real-time optimisation of physical environment to promote situation awareness

Team behaviours:
-shared mental models, role clarity (team briefing), high coordination, clear supportive communication (closed loop), strong leadership while inviting team members to raise concerns, rapid logical decision-making & regular monitoring & review (status updates)

Question 250

How many failed attempts at SGA are permissible in the ANZCA PG61 for CICO?

Answer 250

2

Question 251

How’s the sensitivity & specificity of our current airway assessment tools?

Answer 251

low sensitivity (+ve in disease) & moderate specificity (-ve in health), low +++ prevalence so low PPV—> signs in combination more predictive

Question 252

What are the 9 things to consider when determining appropriate airway Mx plan- what will I consider if yes to any?

Answer 252

1. Hx difficult airway?
2. Does the surgery impact the airway?
3. Are there predictors of difficult BMV?
4. Are there predictors of difficulty inserting & ventilating with supraglottic airway?
5. Are there predictors of difficult intubation?
6. Is there altered cardiorespiratory physiology?
7. Is the patient an aspiration risk?
8. Does the patient have altered cardiorespiratory physiology/reserve?
9. Is there an extubation risk?

Consider awake intubation, regional techniques, postponing or cancelling the case if high risk difficult airway

Question 252

Predictors of difficult BMV?

Answer 252

5 RoCA independent predictors of difficult BMV: FFOES: BMI >26, facial hair, Age >55, edentulous, snoring
Other:
Mask seal issues (facial hair/blood/saliva/anatomical abnormalities such as retrognathia, facial fractures/ abscess/ infection/swelling/ haematoma/ trauma)
Pregnancy
Snoring/OSA/stiff lungs (reduced compliance eg. laryngosapsm, ILD/pulmonary oedema, neck radiation)
If good seal & compliance, can get 50-100cmH2O with BMV
Things we can do to help: shave beard, dentures in

Question 253

Predictors of difficult insertion & ventilation via a supraglottic airway?

Answer 253

Predictors:
Reduced mouth opening
Obstruction @ or below glottis
Distorted airway
Stiff neck or lungs
Good LMA: >=7mL/kg TV, no >15-20cmH2O leak pressure

Question 254

Predictors of difficult intubation? What are the modified Cormack+lehane grades on laryngoscopy?

Answer 254

Predictors:
Combination of TMD (<6cm diff w conventional laryngoscopy), MP, Hx difficulty OR reduced MO (abnorm <3.7cm), obesity, lack trained assistant, reduced neck E

Look (facial shape, trauma, beard)
Evaluate TMD, MO (3F=MO, 3F=mentum to hyoid, 2F=hyoid to thyroid)
MP
Obstruction
Neck ROM

Modified Cormack + Lehane: In optimised position/blade +/- laryngeal manipulation
1: full glottis
2: a: partial glottic obscuration
b: only posterior glottis seen
3: a: able to lift the epiglottis
b: unable to lift epiglottis
4: unable to see epiglottis

Question 255

Predictors of difficult placement of infraglottic airway? what may US assist with?

Answer 255

Surgery of neck
Haematoma/infection
Obesity
Radiation
Trauma/tumour

US may assist at identifying:
-cricothyroid membrane
-subglottic diameter
-tracheal position
-gastric volume
-pharyngeal/laryngeal pathology
-ETT position
-diaphragm displacement for successful extubation/post-extubation stridor

Question 255

Predictors of difficult placement of infraglottic airway? what may US assist with?

Answer 255

Surgery of neck
Haematoma
Obesity
Radiation
Trauma
US may assist at identifying:
-cricothyroid membrane
-subglottic diameter
-tracheal position
-gastric volume
-pharyngeal/laryngeal pathology
-ETT position
-diaphragm displacement for successful extubation/post-extubation stridor

Question 256

What are the most common surgical & nonsurgical risk factors mentioned in coroner’s reports for CICO?

Answer 256

airway infection
congenital abnormalities
malignancy
trauma

Question 257

What should be done if a patient has a CICO situation?

Answer 257

document in patient record, issue airway alert letter

Question 258

What are strong indications for awake fiberoptic intubation?

Answer 258

haematoma
infection
bilateral anterior mandible fracture
mechanical lock
otherwise difficult airway

Question 259

To get fixed obstruction (truncation or flattening of BOTH inspiratory & expiratory flows & increase in FEV50/FIF50 ratio, to what size would the lesion generally have restricted the trachea?

Answer 259

to <1cm

Question 260

SS_HN 1.6: Describe the effects of previous surgery or radiation on the airway (also refer to the Airway management clinical fundamental)
What are some of the airway changes following radiation?

Answer 260

face & buccal mucosa: necrosis & mucositis; early oral thrush/orofacial pain, later ulceration & orocutaneous fistula- may be difficult to hold mask/ventilate, risk friability/haemorrhage

TM joint: fibrosis- risk trismus, difficult laryngoscopy & intubation (may indicat AFOI)

tongue: fibrosis/inflammation: early glossitis, later glossomegaly & reduced mobility. Falsely obscures mallampatti, risks difficult laryngoscopy & haemorrhage

dentition: incr risk caries- early incr mobility, later loss of teeth. risk difficult BMV or dislodgement during laryngoscopy

FOM: fibrosis, reduced tongue mobility, lack of compliance & difficult laryngoscopy (ant column)

mandible: osteoradionecrosis (severe complication of high-dose, frequent radiation to vascular bone- mandible is susceptible as it’s highly vascular), osteomyelitis or pathological fracture- may have asymptomatic dehiscence of mucosa early, later micrognathia, mandibular recession; reduction in mandible space, difficult BMV, difficult laryngoscopy

supra hyoid: fibrosis & oedema- “woody” firm anterior neck tissue, skin tethering, limited atlanto-occipital ROM

lower airway: may have epiglottic/glottic oedema- snoring, voice hoarseness, irritant cough–> difficult laryngoscopy/intubation

Question 261

Some of the considerations/options to intubation when faced with predicted difficult intubation

Answer 261

Ask: does the patient NEED to be intubated
options: local/regional, trache, delay

Question 262

My process for AFOI

Answer 262

Assess thoroughly, consider alternatives (local/regional/awake trache/awake laryngoscopy/delay)

Patient selection (absolute contraindications= patient refusal, relative= LA allergy, bleeding, pt agitation)

Careful consent, discussing topicalisation, sedation, oxygenation, expectations for sensations including “cork in bottle”

Antifog

Ideally oral route (NOT nasal if severe facial or maxillofacial fractures, basilar skull fractures, emergency intubation/significant hypoxia, head injury with raised ICP. Considerations/caution if recent nasal surgery, coagulopathy/anticoagulated, nasopharyngeal obstruction (polyps), suspected nasal foreign body, young children, artificial heart valves (increase risk bacteria during insertion). (suspected epiglottis is a CI if blind nasal intubation, may be OK with AFBI))

Sedation & antiSialagogue: remifentanil TCI (1-3ng/mL Ce), small amount midaz (0.5-1mg) + fentanyl (25-50microg)- care if using >1 agent. Propofol risk apnoea.
Give 200microg glycopyrrolate just before start sedation (20mins)

Topicalisation:
work out maximum dose- lignocaine 9mg/kg lean body weight

co-phenylcaine nasal spray- each spray 5mg lignocaine. 4 sprays/nostril= 40mg
Option 1 for the remainder:
can gargle 2% lignocaine viscous- 4mL= 80mg (can get on the lens)
MAD 4% (6mL= 240mg)
another 6mL 4% for spray as you go (240mg)
that= 600mg, within the range for a 170cm tall person.

Option 2:
Just use 2% with the MAD, with patient already positioned (could therefore use 25mL of 2%, with the 40mg cophenylcaine for nostrils with pt deeply sniffing)
Endpoints for topicalisation:
-no gag to soft palate touch (pt can self-test with yanker)
-voice change
-no cough when spraying down to cords

Option 3:
-Madgic device connected to rigid port of 3-way chooks foot. Device for delivering LA attached at 1 port, the other occluded. O2 flow 2L/min on video (Karl’s lecture said 6-8L/min- pressurised LA + HFNO + deep yawn/breath topicalises cords well)
-Do the nasal topicalisation
-6mL 4% lignocaine for back of pharynx (3-4mL as deeply inhale, break, then bend insert sideways & angle to cords- another 2-3mL as deeply inhale).
-then have at least another 6mL up our sleeve for spray as you go if 160cm pt

Winnie’s:
cophenylcaine nostrils
10% a couple of sprays back of throat
MAD with 2% angled back ask to inhale w each expecting a cough (VCs)
then SAYG, aim not to touch mucosa

Test with soft suction catheter nose & back of throat/pharynx- pt should tolerate sans reaction

endpoints: no gag to test
voice change
no cough when spraying down to cords

Oxygenation:
HFNO 30L/min initially, turn up to 70 as pt tolerates (can use in 1 nose if nasal route used, or can use a Hudson cut in half. Or could use nasal prongs at mouth (gives a better capnography reading)).

Positioning & performance
Patient positioned before sedated, sitting up with table broken in middle.
Ergonomics vital- I stand at pts R) hip so I can see patient, monitors to L) of pts head & anaesthetist doing sedation to R) of pts head & reach everything I need. Anaes nurse @ pts L) hip
One for sedation, one for manipulating scope & then passing tube

Reinforced parker tip ETT (less change of hang-up at cords) 0.5 to 1 size down from oral adult tube (children age/4 + 3.5 cuffed)- ensure well-lubricated if using blue tube but don’t get lube on lens
*warn the patient that it’ll be difficult to breathe at the point when the tube is railroaded on

2-point confirmation before induce.

Question 263

what are the end-points for topicalisation for AFOI?

Answer 263

no gag to soft palate touch (pt can tolerate soft suction catheter in nose & soft palate)
voice change
no cough when spraying down onto cords

Question 264

What’s the safest way to change a nasal or reinforced ETT to a standard oral ETT in a patient with a difficult airway?

Answer 264

place AEC through nasal tube
under direct videolaryngoscopy, deflate cuff of nasal tube & withdraw it approx 5cm (keeping AEC in). Advance oral tube alongside the AIC through cords. Confirm EtCO2 via the oral tube. Remove the nasal tube, however safe to keep AEC in (care w nasal trauma)

Question 265

Pre-assess including contraindications & precautions for nasal intubation?

Answer 265

Check indiction (pt or surgical factors)
ask about epistaxis & anticoagulants & nasal surgery
nostril patency
cophenylcaine, consider softening tube in warm water

Contraindications:
patient refusal
base of skull #
midface disruption (depending on # location, surgeons may specifically request nasal tube)
significant hypoxia or other situation requiring emergency intubation/surgical airway
head injury with raised ICP

Cautions:
coagulopathy/anticoagulated, epistaxis
nasal obstruction (polyps)
suspected nasal foreign body
recent nasal surgery
prosthetic heart valve (risk bacteraemia during the insertion)
if blind, epiglottis a contraindication but OK if AFBI
young children?- may be more challgenging to place nasendotracheally with the anterior/cephalic position of the airway

Question 266

What are patient & surgical factors indicating nasal intubation?

Answer 266

Patient:
-oral intubation not possible (eg. tongue oedema, small/no mouth opening
-limited neck mobility or unstable C spine (for AFBI)
-improved pt tolerance (but there is risk nasopharyngeal pressure areas)

Surgical:
-dental procedures
-oropharyngeal surgery
-operations on maxilla & mandible

Question 267

size for nasal ETT?

Answer 267

0.5-1 size down from oral tube size for adults
generally 7mm for men, 6mm for women big enough
children, age/4 + 3.5 cuffed fine

Question 268

Process for throat packs

Answer 268

retention= a “never event” so should have robust process

as per DAS, we shouldn’t routinely insert

Discuss indication at pre-OT huddle

Should be radio-opaque & included in the surgical count (a counted surgical sponge)

Call out to room when inserted (surgeon, anaes & scrub nurses, anyone taking over for breaks needs to know, on scrub count), have a least one visual reminder (hanging out of pts mouth, attached securely to airway device, note attached to pt face/airway device) on pt and obvious visible written reminder (on whiteboard, anaes machine)

Call out to room when removed & document time of insertion/removal on anaesthetic & surgical count records.

Have as MANY checks & balances as possible- particularly high risk w long case. eg. icon on anaes record, note on APL valve.

Question 269

Some of the issues/conflicting goals with shared airway?

Answer 269

Communication vital- surgeon & anaesthetist discussion re: exactly what surgery entails & anaes communicate if any change in pts condition (eg. desaturation)

requirement for:
-immobile surgical field
-unobstructed access to surgical field for surgeons
-limited airway access in event of an issue
-maintenance of anaesthesia
-maintenance of airway potency, oxygenation, ventilation

Question 270

Options for anaesthesia for shared airway procedures?

Answer 270

LA/topical +/- sedation: only very minor procedure, cooperative patient

Spont vent GA: TIVA with hi flow (strive-Hi), or inhalational induction (good for spont breathing but limited ability to deliver if no airway device- can administer through side port of rigid bronch)

IPPV with MLT: obscures 1/3 of glottis for surgeons

LFJV

HFJV

Question 270

SS_HN 1.3: Indications for low frequency jet ventilation & how done?

Answer 270

micro laryngeal surgery & rigid bronchoscopy

high pressure O2 gas source (wall supply 4atm) is attached to a narrow cannula via pressure-regulating valve

cannula can be inserted transcutaneously, via rigid bronchoscope or as a separate tube (eg. hunsakker catheter)

generally ventilate at max 10 breaths/min to allow adequate exp time (eg. with a hand-triggered device such as sanders injector or manujet)

can ventilate open airway but operative field NOT immobile.

just requires simple gas injector, however airway pressure monitoring is not possible (ensure the pt RELAXED, hand on diaphragm to help ensure not over-inflating), high risk barotrauma (esp if below the larynx), can get gas entrainment & airway gas monitoring is difficult (no EtCO2), MUST use TIVA (can’t deliver volatile). risk gastric insufflation if poorly aligned.

emergency oxygenation: not a form of ventilation (doesn’t remove CO2)

Heard recommends in CICO situation, to use rapid O2 or LeRoy devices.
Procedure:
-Rapid O2 device (gives good tactile feedback) connected to oxygen cylinder, 15L/min.
-hold for 4 secs (1L O2)- seek feedback re: chest rise or signs of obstruction- this breath should incr saturations. wait for over 20 seconds for a peak in SpO2, after SpO2 drop 5% from maximum, further 2secs insufflating (500mL)
-pressure delivered w 4sec breath approx 40cmH2O. Large lumen of LeRoy or rapid O2 allows pressure release without having to disconnect.
if no response after 20 ecs, additional jet of 20secs.

-Manujet can deliver 250-1000mL/second @ expense of high airway pressure. reducing the pressure to 1 bar gives 250mL/sec, 4 bars 1L/sec. Need to disconnect to allow deflation. only use manujet if unsatisfactory SpO2 response w LeRoy or rapid O2 & only use manujet if patent exp pathway. Manujet doesn’t provide feedback.

All risk significant risks esp if jet misdirected, eg. subcut emphysema, barotrauma (esp if obstructed upper airway)
3-way tap closed for jet oxygenation dangerous ++, exposes airway to uncontrolled pressures.

inadequate gas exchange common.

if airway unsecured & supraglotic, risk blowing debris into trachea

Question 271

what’s high-frequency jet ventilation? some of the complications?

Answer 271

heated, humidified jets delivered at 1-10Hz

requires specialised ventilators & familiarity w the technique.
onset & offset of inspiration controlled by high-freq flow interruptor

administered via narrow cannula attached to suspension laryngoscope, longer catheter placed sub-glotically or via a cricothyroid cannula

air is entrained but TVs are much smaller than conventional ventilation.
can adjust frequency of ventilation, insp time (usually 30% of cycle) & driving pressur of gas.

Provides immobile surgical field but difficult to monitor CO2

complications:
Barotrauma: PTx, pneumopericardium, pneumomediastinum, subcut emphysema, hypotension, RV failure
Dry gas: mucosal trauma, tracheal necrosis, atelectasis (however ventilators that heat & humidify & continuously monitor airway pressure have been developed)
Impaired ventilation: hypoxia, hypercapnia
unprotected airway: risks airway soiling by debris, secretions, vomitus

Question 272

What are some of the advantages of using lasers for ENT surgery?

Answer 272

precision
easier control of bleeding
removal of tissue by vaporisation
able to reach distant pathology without compromising the airway (particularly in small children)
less oedema from tissue handling

Question 273

what are the sequelae of airway fire?

Answer 273

life-threatening airway obstruction
thermal injury to mucosa, skin, airways
inhalational injury from toxins (eg. HCl released from burning PVC ETT)

Question 274

IV lignocaine onset & peak?

Answer 274

45 secs, peak 5 mins

Question 275

absolute & relative contraindications for jet ventilation?

Answer 275

active asthma (hyperinflation if incr compliance)
pneumonia (hypoventilation if incr resistance)
relative: coagulopathy, morbid obesity if baseline poor oxygenation, tracheal obstruction if inexperienced operator

Question 276

entrance ports on rigid bronchoscope?

Answer 276

wide axial access: for optical device (eg. flexible or rigid scope, clips, dilation balloons, stents) with integrated video access
oblique lateral access: for suction, laser, coagulation probe
lateral access: for ventilation

Question 277

best mode of GA for rigid bronchoscopy?

Answer 277

TIVA with short-acting agent (prop/remi, roc)

Question 278

SS_HN 1.12: Discuss the anaesthetic management of patients requiring thyroid or parathyroid surgery. In particular:

• Use, effects and complications of thyroid hormones or anti-thyroid drugs used to stabilise patients peri-operatively (also refer to the Peri-operative medicine clinical fundamental)
  -What are advantages & disadvantages of PTU vs carbimazole?
• The effects and management of hyper and hypo-calcaemia
  -what’s normal serum calcium?
  -what’s the physiologically important Ca++ measure?
  -how may hyper or hypoAlb impact Ca++ measurements?
  -How do you calculate corrected calcium in hypoalbuminaemia?
  -What would you class as mild, moderate & severe hypercalcaemia?
  -What are clinical manifestations of hypercalcaemia? additional signs of HPTH?

-What are the most common causes of hypercalcaemia? Rough ways to distinguish?
-other causes hypercalcaemia?

-Ax?

-how to treat hyper Ca++?

-What’s the most common clinical presentation of primary hyperparathyroidism?

-What’s parathyroid crisis?

-etiologies of hypoCa++?

-What are the symptoms & signs of hypocalcaemia?

-How to treat hypocalcaemia?

• Potential airway management issues and their assessment including in the patient with a retrosternal goitre
  (also refer to the Airway management clinical fundamental- see periop
• Surgical positioning and the implications for patient protection and access

-What’s are positioning considerations common to thyroid & parathyroid surgery or specific to parathyroid?

• Airway, surgical and endocrine complications in the perioperative period and their management

-what are some postoperative complications with thyroid surgery?

-When is a NIM tube indicated? Where does it sit? Considerations?

-What are the implications of unilateral & bilat VC injury?

• Rates of transient RLN injury with thyroid & parathyroid surgery? permanent? What’s the NPV of NIM ETT for RLN injury?

-what are manifestations of superior laryngeal nerve injury?

-what are manifestations of injury to vagus nerve near carotid bulb?

-what anaesthetic strategies may limit the risk of postop haematoma?

-what’s the mechanism of post-thyroidectomy haematoma & implications?

What the recommendations by DAS in their management of haematoma after thyroid surgery guidelines with respect to:
-postop monitoring?

-early signs to look out for that may indicate post-thyroidectomy haematoma?

-what about hypoxaemia & increasing O2 requirement?

-immediate management if ANY of the DESATS signs?

-what should be in the emergency box that should be bedside (incl during transfers) for all pts who had thyroidectomy with anterior approach? What else should be available for pts who’ve had thyroid surgery?

-What post-event actions should be taken after evacuation of post-thyroidectomy haematoma?

-What’s another DAS recommendation to support systems for successful identification/management of post-thyroidectomy haematoma?
-What’s the minimum observation period post day case thyroidectomy?

-what are some clues that a pt may be @ risk of tracheomalacia, what test can assess risk & what should be done if +ve leak test?

-How soon after thyroidectomy & why may hypocalcaemia occur?

-rate hypoparathyroidism after total thyroidectomy?

-what intraoperative test can be used to predict risk postoperative hypoparathyroidism?

-do patients after thyroidectomy need thyroxine?

-What are the main complications following parathyroidectomy?

-Why & how may intra-operative parathyroid hormone monitoring be performed during parathyroidectomy for hyperparathyroidism?

-is much pain expected after thyroidectomy?

Answer 278

Both are thionamide drugs, meaning they inhibit thyroid hormone synthesis in the thyroid gland. PTU also inhibits the peripheral conversion of thyroxine (T4) to T3.

Carbimazole is completely metabolised to methimazole, the carbimazole dose required to yield equivalent methimazole is 40% higher.

Methimazole has advantages including longer serum half-live (4-6hrs vs PTU 75 mins, and the intra-thyroid methimazole can remain high for up to 20hrs). Carbimazole benefit of once-daily dosing, more rapid achievement of euthyroid state.

Both ass’d w pruritis, rash, arthralgias, fever, abnormal taste, N&V. About 50% of pts have cross-sensitivity for skin reactions. If there is serious allergic reaction or agranulocytosis, shouldn’t substitute the alternative, should do radioiodine or surgery.

Both teratogenic but methimazole higher than PTU so use PTU 1st trimester of preg. Both are pregnancy category D.

Agranulocytosis.

Hepatotoxicity- PTU can cause fulminant hepatic necrosis. Should measure LFTs prior to thionamide therapy.
PTU: ANCA-+ve vasculitis
Methimazole pancreatitis.

Pt must be clinically & biochem euthyroid prior to elective thyroid OT to minimise risk periop thyroid storm
Takes 6-8wks, delay due to large store thyroid hormone in colloid
Need resting HR <80/min, no tremor
TFT should have normal T4, TSH may remain depressed

2-2.5mmol/L (ionised 1.2-1.4mmol/L)

ionized serum Ca++

hypoalb may have normal total serum Ca++ but Dx of hyperCa++ may be overlooked if ionised serum Ca++ not checked. hyperalb may have elevated serum Ca++ due to proportionally increased binding of Ca++ to Alb but the serum ionized Ca++ may be normal (pseudohypercalcaemia).

CCa = serum Ca + (0.8*(40 – serum Alb))

<3mmol/L
mod 3-3.5
severe >3.5mmol/L

CNS
Decreased concentration, confusion, fatigue, if severe: stupor/coma
CV:
Shortened QT interval, bradycardia, HTN, if longstanding (eg. w primary hyperparathyroidism, Ca can be deposited in heart valves & coronaries & myocardium–> HTN, cardiomyopathy)
Musculoskeletal:
Weakness, bone pain/osteopaenia/osteoporosis (PHPTH)
GIT:
Anorexia, N& V, bowel hypomotility or constipation, pancreatitis, PUD
Renal:
Nephrolithiasis/nephrocalcinosis, polyuria, polydipsia, RTA, nephrogenic DI, acute & chronic renal insufficiency

Additional signs of PHPTH:
Hypophosphatemia
High vit D
Mild hypomagnesaemia (PTH stimulates Mg++ reabsorption but hypercalcaemia inhibits it)
Anaemia: normochromic, normocytic.

Primary hyperparathyroidism & malignancy
Malignancy usually clinically evident. Primary HPTH gen borderline or mild hyperCa but malignancy higher.

PTH-mediated (primary hyperPTH, MEN syndromes, familial hypocalciuric hypercalcaemia, tertiary hyperPTH (renal failure))
non-parathyroid (illnesses with granulomas eg sarcoid which increase vit D)
Med: thiazides, lithium, theophylline
Misc: hyperthyroidism, acromegaly, pheochromocytoma, adrenal insufficiency, milk-alkali syndrome (hyperCa++, met alk, renal impairment due to ingestion of Ca++ & absorbable alkali)

-clinical Ax (meds, FHx, duration, symptoms). measure PTH. if elevated, likely PHPTH. if not look for PTHrP (high may be malignancy), if that’s not high check vit D, if elevated may be granulomatous disease or lymphoma. if not, measure serum light chains may be elevated in multiple myeloma but if normal something else like vit A excess, hyperthyroidism.

-Rx by lowering serum []Ca++ & correcting/managing underlying cause; if mild, avoid triggers (eg. volume depletion, prolonged bed rest, thiazides, Ca++ supplements & ensure adequate hydration). moderate same precautions + /- if acute rise, saline hydration & bisphosphonates. Severe (>3.5) have changes in sensorium, IV isotonic saline, subcut calcitonin 4U/kg, bisphosphonates (zoledronic acid, reduce rate of infusion/dose in renal failure); the saline & calcitonin should improve Ca++ in 12-24hrs, the zoledronic acid by the 2nd-4th day. Saline helps by correcting volume depletion which exacerbates hyperCa++ by impairing renal Ca++ Cl.

Asymptomatic hypercalcaemia

Symptomatic severe hypercalcaemia (eg. Coma)

low PTH (genetic, post-op, autoimmune, infiltration, radiation, hungry bone). high PTH (secondary hPTH in response to low Ca++): vit D def or resistance, PTH resistance (eg. hypoMg++), renal disease, loss of Ca++ in circulation (hyperphosphatemia, tumor lysis, acute pancreatitis, acute resp alkalosis, sepsis), drugs (bisphosphonates, calcitonin, denosumab, Ca++ chelators (eg. citrate, w blood transfusion), IV contrast may interfere w lab measure of Ca++, phenytoin. hypoMg++ decrease PTH secretion or cause PTH resistance.

-mild= perioral or acral (hands/feet) paraesthesias, anxiety (exac by hyperV).
-moderate= muscle twitches/cramps
-severe= papilloedema, seizures, trismus or tetany, laryngeal spasm, ecg changes (QT prol, osborn (J) waves, also hypoCa++ may cause K+ efflux & hyperkalaemia)

-symptomatic hypocalcaemia requires replacement- if mild may be PO 1500-2000mg daily in divided doses (calcium carbonate (citrate if on PPI or have had gastric bypass).
Some may also need vit D (1000IU/day) since postop hypocalcaemia is more common in pts with severe preop hyper Ca or chronic vit D defic.
Severe hypoCa++ requires IV & PO replacement & Rx of concomitant hypomagnesaemia.
Rx also depends on the cause;
-Of the pt has low or N phosphate & high or N PTH, hungry bone syndrome (Ca++ straight into bone in response to drop in PTH), need to correct the Mg++ (since low Mg++ diminishes PTH secretion), Rx Ca++ w PO or IV or even dialysis, hyperK correction in renal failure pts
-if hypoCa++ ass’d w hyperphosphatemia & low PTH, hypoparathyroidism is diagnosed which requires Rx w calcitriol

Thyroid surgery:

Pre-op Ax:

-disease control (hyper/hyposecretion)- S&S, levels, Rx (Hx, exam, Ix)

is there retrosternal extension
-most common symptom exertional dyspnoea (when trachea <8m), positional (maneouvers that force thyroid into thoracic inlet eg. reaching), stridor & wheeze @ rest if trachea <5mm. cough, choking sensation, OSA (unable to lie flat), dysphagia, voice hoarseness, stridor.
SVC obstruction (eg. pre-syncope/plethora if elevate ULs, cerebrovascular steal.
horner’s if compression Cx sympathetic chain

other Ax:
Size, nature & position of goitre; if present for some time may be ass’d w post-op tracheomalacia.

If malignant, may be ass’d w immobile airway distortion/obstruction (anywhere from glottis to carina), there may be cord palsies, distortion & rigidity of surrounding structures, possibility of intraluminal spread; heralds potentially difficult airway, consider AOFI or spont breathing technique (beware cork in bottle)

Pts with significant resp symptoms, unable to lie flat, stridor or >50% narrowing on CXR or co-existing predictors of difficult intubation also warning sings of difficult airway

exam: if unable to feel bottom of goitre. idea of size, tracheal position, Ax for Pemberton’s, pleural or pericardial effusion

FNE to see mobility of VCs

imaging to see retrosternal spread, size of trachea (*discuss with surgeons re: likelihood of mobility of narrowing).
-a reinforced ETT generally can negotiate tracheal deviation or compression even w benign large goitre.

Anaes:
shared airway, limited access. secure careflly w tape
prop/remi TIVA (assists not needing relaxant, coughless extubation)

Procedure:
NIM monitoring may be required (d/w surgeons)
head & neck E (sh rolle), head up tilt, arms wrapped @ sides (use IV etensions), eye padding/lubricaiton & tape (shared airway)

Plan:
airway plan A/B/C; if marked laryngeal displacement or other featurs of difficult airway, consider AFOI but if stridor, risk cork in bottle (warn pt)
consider spont breathing
& these pts likely have difficult SGA placement, difficult ++ trache, need difficult airway trolley & only back-up option for failure may be rigid bronch. if difficulty anticipated, have this in room. consider neck US.
In most cases, standrd incduction & normal or NIM tube.

Potential complications;
RLN injury; Ax w FNE, may require speech therapy, OT or trache
bleeding (cough-free extubation)
thyroid storm (euthoyroid preop)
hypocalcemia
tracheomalacia
carotid sinus (haemodynamic instability)
air embolus
PTx

-for both thyroid & parathyroid: lim’d airway access once prepped/draped, neck position cautions (sh roll, extension, if pt has neck pathology get it Ax/Mx prior to elective OT, headrest), ULs tucked (lim’d UL access for IVs & BP cuff)
-Parathyroid may be done with superficial cervical plexus block +/- MAC or GA; former suitable for a localised single gland & procedure expected short duration. Cx plexus block may reduce pain, N&V but inappropriate if pt refusal, anxiety/claustrophobia, to lie still/cognitive impairment, difficult airway, extensive tumours.
-An oro- or nasogastric tube may be placed to facilitate palpation of a gland deep in tracheooesophageal groove.
May have intra-op PTH monitoring.

-RLN damage (w VC implications- weak voice, stridor, airway obstruction, esp after bilat surgery. Injured VC median/paramedian position)
-hypocalcaemia (if parathyroid glands accidentally removed)
-haematoma +/- laryngeal oedema/tracheal compression or haemodynamic compromise
-tracheomalacia/failed extubation if longstanding tracheal compression form the mass
-horner syndrome, tracheal or oesophageal injury

-some use routinely. Existing data don’t support that routine use reduces incidence of RLN injury but more strongly indicated for high-risk procedures (eg. repeat surgery or malignant adhesions) or for low-volume surgeons). placed with surface electrodes @ level of cords during intubation (so that the cords come in contact with the electrodes, during surgery VC response to RLN or vagus n stimulation is shown with auditory or visual EMG signals). NMB avoided during maintenance, so either intubate with prop/remi (eg. 1-2 microg/kg bolus 60secs prior to intubation or use roc & reverse);
unilat injury= voice hoarse, contralat= stridor/obstruction requiring immediate intubation & occasionally tracheostomy.

RLN injury & hypoparathyroidism are higher risk if re-operative thyroid surgery.

-0.4-3.9%, permanent up to 3.6%
100% NPV for NIM ETT

-no airway compromise, voice fatigue/changes in voice quality (eg. speaking in loud voice, high notes)

-vagus nerve injury= paralysis of both SLN & RLN, both sensory & motor deficits to larynx (aspiration risks)

-pre-op: smoking cessation advice, ideally avoid surgery if URTI/LRTI, check platelets/LFTs/coags, withhold anticoagulants appropriately.
Intra-op: Aim for coughless extubation: suction deep, lignocaine prior to extubation or remifentanil useful.
Multi-modal anti-emesis (dexamethasone, TIVA, ondansetron & 2 additional agents of recovery, limit emetogenic agents (eg. nitrous)).

-Expanding haematoma may directly compress trachea but primarily risk causing venous congestion/oedema of airway structures; this may make laryngoscopy difficult, airway difficulty & compromise may be rapidly progressive, important to evacuate the haematoma prior to intubation attempts if signs of respiratory compromise, the oedema may take time to resolve so the pt may need to go to ICU intubated following haematoma evacuation.

-Close postoperative observation is vital, pts after thyroid surgery should be monitored in an environment with staff trained in recognising the early warning signs of post-thyroid haematoma & instigating appropriate initial management & escalation.

-Difficulty swallowing/discomfort, increasing EWS, swelling, agitation/anxiety, tachypnoea/difficulty breathing, stridor

-desaturation & increasing O2 requirement are late signs of airway compromise

-OXYGENATE- FiO2 100%, 15L/min via NRB
-Head upright 45deg to lower venous congestion
-Concurrent evaluation of airway patency & immediate management; airway compromise (stridor, tachypnoea, desat), immediate senior surgeon & anaesthetic R/V, remove clips/sutures with SCOOP (skin exposure, cut sutures, open skin to expose strap muscles, open strap muscles to expose trachea, cover neck w pack)
If no improvement in airway compromise, intubate:
-should secure airway without delay due to expanding obstruction, by most experienced team member, limit attempts beyond 3+1
-depending on severity/pace of expansion & clinical stability, either transfer to OT w monitoring or (more likely) by bedside; have surgeon ready for emergency FONA (scalpel bougie or emergency tracheostomy reduce risk gas trapping & optimise gas exchange/oxygenation cf cannula + less complications eg. subcut emphysema, barotrauma, hypercapnia & obstruction), plan A AFOI/laryngoscopy or surgical trache if pt cooperative & stable & airway patent enough & adequate SpO2, consider direct laryngoscopy w spont breathing if uncooperative & have time, otherwise try RSI with 2-person technique videolaryngoscopy/fibreoptic tube railroaded with rescue FONA.
*may need bougie/smaller tube, must place ETT below obstruction, FOB to confirm, HAVE DIFFICULT AIRWAY TROLLEY wherever pt intubated & in PACU.
Can consider dexamethasone, TxA as temporising strategies & FNE if immediately avail by experienced operator but there should be no delay to surgical evacuation (definitive Rx).
They should go to ICU post-op (may require overnight intubation to allow supraglottic oedema to subside).
-If pt stable & not immediate airway compromise, need to arrange on-site senior surgical R/V, FNE, IV dexamethasone & TxA, consider timing of T/F to OT (may need t/f to ICU or PACU for closer observation in interim).

-guidelines for Mx of suspected haematoma following thyroid surgery (cognitive aids)
-SCOOP guideline
-artery clip
-tissue. &artery forceps
-scalpel
-scissors
-sterile gauze or medium wound pack
-gloves
-staple remover if staples used or suture cutter x2
Equip for FONA: size 10 scalpel, bougie, cuffed 6.0mm ID TT

Reporting of critical incident in national databases, Q&S team for M&M meeting feedback
Psychological debrief to patient before & after discharge; offer referral for clinical psychology. Letter of candour describing what happened & offering support.
Hot & cold team debrief, offer psychological support to staff (eg. ANZCA doctors support program)

Institutions performing thyroidectomies should have a nominated local risk lead to coordinate multi-D staff training, eg. could be the local airway lead.Regular multi-D training & attainment/maintenance fo competencies for all staff potentially involved in care of these pts, teaching should prioritise simulation, encourage appreciation of anatomy & multi-D team dynamics & familiarisation with protocols & requirements (eg. contents of post-thyroidectomy emergency box, cognitive aids)

6hours

-longstanding compression by goitre (may cause atrophy/erosion of cartilaginous tracheal rings & tracheal wall may collapse in AP direction after thyroid resection).
Cuff leak test to Ax adequacy of airflow around ETT prior to extubation (still used despite limited predictive value, +ve leak test if <110mL diff between exp TVs w cuff down). If no leak, extubate over tube exchanger (which is never inserted beyond 25cm in adult, distal tip must remain above carina, secure in midline, label to avoid confusion w OGT) to facilitate reintubation if necessary. pt should go to ICU if have a tube exchanger.
Generally even with LARGE goitre, don’t need AFOI for benign thyroid mass

-days after, due to damage or resection of parathyroid glands

-2%

-intra-op indocyanine green angiography, assessing the perfusion of the parathyroid gland

-depends on the indication, if benign disease & total thyroidectomy not for hyperthyroidism, typically commence it 1.6mcg/kg. if hyperthyroidism, often consider calcium & vit D, thyroid replacement depends on size of surgical remnant. if pt was hyperthyroid pre-op, wait until euthyroid. 20% lower dose in elderly or CAD risk due to risk over-replacement.
persistent hyperTh after OT for Graves should be Rx w radioiodine.

-Operative failure, symptomatic haematoma, hypocalcaemia (classic Ca++ nadir occurs within first 24-48hrs after parathyroidectomy as a result of suppression of the remaining glands which require the + of hypoCa++ to resume function, Ax serum PTH day 1 to confirm function of residual Parathyroid tissue. Should also replace vit D if was deficient pre-op). wound infection. RLN injury (rare but higher risk w repeat surgery so may do pre-op laryngoscopy to Ax VC function & intra-op neuromonitoring). May get hyperthyroidism from manipulation of the thyroid gland.

-To indicate whether hyperfunctioning parathyroid tissue has been adequately excised, to avoid failure rates (shown in meta-analyses to have higher cure rates). Have a baseline value. Draw blood sample (eg. from foot as ULs tucked in) after believe adenoma resected. PTH has short plasma half-life (3-5mins). Rapid assay can produce results while pt still in OT. Reduction of @ least 50% PTH from baseline= success, some centres want “dual criteria”- PTH in normal range.

-minimal pain; educate, paracetamol, NSAIDs, if any opioid (unlikely), lowest effective dose & IR (eg. <10 OME’s)

Question 279

SS_HN 1.1: Describe the anatomy and innervation of the face, external ear, neck, nasal passages, pharynx and larynx with reference to the performance of regional or topical anaesthesia for head, neck or ear nose and throat procedures.

what’s the sensory supply to the face?

branches of V1?

what supplies muscles of facial expression & other special functions??

muscles of mastication?

Sensory supply to ear?

larynx structure?

vascular supply to thyroid?

How to block glossopharyngeal nerve
how to block SLN

Answer 279

sensation to face is through the branches of CNV (trigeminal) which has it’s trigeminal ganglion in the petrus temporal bone in middle dranial fossa:

-ophthalmic division to upper third of face, incl eye & nose to tip. maxillary mid face incl infraorbital nerve region & upper lip. mandibular lower third (incl lower lip).

-ophthalmic branch V is purely sensory, moves through cavernous sinus & before entering sup orbital fissure, divides into 3 branches:
-frontal (divides to supraorbital & supratrochlear)
-nasociliary (supplies ant ethmoid & external nasal (supply internal nasal cavity & skin @ apex & ala of nose), internal nasal (mucus membrane of septum, lateral wall nasal cavity), infratrochlear (lacrimal sac/caruncle), post ethmoid (ethmoid & sphenoid sinuses), short & long ciliary nerves (eyeball)
the nasociliary provides sensation to cornea, perilimbal conjunctiva & superionasal peripheral conjunctiva- it passes intra-conally to supply long & short ciliary nerves. The lacrimal & frontal nerves supply sensation to the remaining peripheral conjunctiva. They pass extra-conally so may be missed by a retrobulbar block
-lacrimal (skin & conjunctiva of lateral portion of upper eyelid). ALL sensory.

-maxillary division also purely sensory. it gives off:

-middle meningeal nerve in the cranium then exits via foramen rotundum.
-in the pterygopalatine fossa it gives off several nerves from the pterygo-palatine ganglion incl PG PSNS fibres to innervate lacrimal gland (via zygomatic nerve), sensory fibres to orbit/nose/palate/pharynx
-NASAL branches innervate post aspect of nasal septum, mucous membrane of sup & middle conchae
-NASOPALATINE nerve supplies ant nasal septum, floor of nose, anterior palate
-GREATER (hard palate) & LESSER (soft palate) palatine nerves
-PHARYNGEAL branch.

As the maxillary nerve passes through inferior orbital fissure, it becomes the INFRAORBITAL nerve, with branches:
-ANT SUP ALV NERVE, sometimes middle superior alveolar nerve
-INF PALPEBRAL (supplies skin of lower eyelid)
-LAT NASAL (lateral aspect of nose)
-SUP LABIAL (skin & mucous membranes of upper lip)
Zygomatic nerve also exits the inferior orbital foramen, zygomaticofacial supplies skin over malar prominence & zygomaticotemporal supplies skin over side of forehead, also some supply to lacrimal gland.

Mandibular branch: has motor (masseter, temporalis, pterygoids, tensor tympani, tensor veli palatini) & sensory:
-buccal which provides sensory to skin of cheek, buccal mucosa & gingiva in mandibular molar region
-lingual (sensory innervation to ant 2/3 tongue, mucosa floor of mouth, lingual gingiva)
-auriculotemporal (passes behind TMJ, skin of auricle, EAM, tympanic membrane, temporal region, TMJ, parotid gland)
-inferior alveolar (travels close to but post/lat to lingual nerve, gives off mylohyoid nerve (supplies mylohyoid & ant belly digastric), the inf alveolar becomes mental nerve as exits mental foramen.
Muscles of facial expression by CNVII (travels through canal in temporal bone), which also provides sens’n ant 2/3 tongue & sublingual/submandibular salivary glands & lacrimal gland).

motor function muscles of mastication by:
CNV (eg. masseter, temporallis, pterygoids, mylohyoid, ant belly digastric, tensor veli palatine, tensor tympani by V3)
VII: buccinator
suprahyoid by a mixture of VII, V3
infrahyoid by C1-3
IX & X

external ear: auricle= auriculotemporal (and skin in front of ear, EAM, TM, TMJ), pinna= greater auricular nerve, in btwn= lesser occipital nerve, middle part= auricular branch of vagus.
external auditory canal= facial nerve, auriculotemporal nerve, auricular branch of vagus.
Tympanic membrane supplied by auriculotemporal nerve, auricular branch of vagus & jacobson’s nere(tympanic, from glossopharyngeal)

relevant to macs facs:
Mandibular condyle rotates & translates anteriorly when mouth opens. meniscus (overlying condyle) forms a hinged joint with the condyle allowing rotation, meniscus & temporal bone form a sliding joint, allowing translation.

Inf rectus is frequently entrapped with fractures of orbital floor. orbicularis oris frequently requires repair w perioral lacerations.

LARYNX:
hyoid bone (C3)
9 cartilages:
3 paired (arytenoids, corniculate, cuneiform)
3 unpaired (thyroid, cricoid, epiglottis)

ligaments:
thyrohyoid, hyoepiglottic, cricothyroid, cricotracheal

intrinsic muscles:
cricothyroid (supplied by ext branch SLN)
all others by RLN (post (abd)/lat (add) cricoarytenoid, interarytenoid (adduct), thyroarytenoid & vocalis (tense VCs))

extrinsic (supplied by ventral rami C1-3)= sternothyroid, thyrohyoid, inf constrictor

superior laryngeal artery (from sup thyroid) & inf laryngeal (from inf thyroid), drains into sup & inf thyroid veins

Block CN IX w LA caudal to palatopharyngeal fold, 5mL/side, highly vascular so coagulopathy= relative contraindication

block SLN by nebulisation or mucosal saturation or by injection of LA lateral to hyoid cornu or in the pre-epiglottic space, 2cm lateral to thyroid notch

block RLN (sensory to VCs & trachea) via transtracheal injection; can insert a plastic IV cannula to limit trauma w coughing following injection. cough is deliberate, disperses LA along airway & cords.

Question 279

SS_HN 1.19: Describe the innervation of the teeth and regional blocks used for dental procedures

Answer 279

Local infiltration anaesthetises terminal nerve endings, indicated for individual tooth or isolated area, intra-oral.
field block anaesthetises terminal branches
nerve block anaesthetises main branch

nerve block may be preferred to LIA for approximating wound edges as they don’t distort tissue

blocks are intra-oral, for dental procedures or neurolysis of chronic tooth pain.

Blocks are for maxillary (V2) & mandibular (V3) branches of trigeminal nerve (CNV)

-Blocks for divisions of maxillary nerves:

infraorbital

it’s branches:
a) anterior superior alveolar nerve (supplies ipsilat central incisor, lateral incisor & canine) & sometimes the middle superior alveolar nerve (supplies 1st & 2nd premolars & part of 1st molar).

The posterior superior alveolar nerve (supplies part of 1st, all of 2nd & 3rd molars) & sometimes the middle superior alveolar nerve branch from maxillary nerve

b) greater palatine (supplies posterior palate, distal to canines), nasopalatine (supplies ant palate):
-anterior superior alveolar nerve: innervates from canines to midline (ie. ipsilat incisors & canine); infraorbital nerve block
-middle SAN: innervates ipsilat premolars & 1st molar; infraorbital nerve block
-Posterior SAN: ipsilateral molars, from maxillary nerve
-Greater palatine nerve block: innervates ipsilateral palate (distal to canines) & molars
-Naso-palatine: frontal/medial teeth

Blocks for mandibular nerve branches (inf alveolar, lingual, buccal, mental):

-inf alveolar: blocks ALL mandibular teeth to midline, blocks the hemi-mandible, useful for painful mandibular conditions & their Rx.

-lingual: ant 2/3 tongue, floor of mouth, medial (lingual) gingiva; is typically incidentally anaesthetised w the inf alv nerve block
-mental nerve: sensation to lower lip, mucosa lower lip, lateral mucosa/gingiva over lower incisor teeth/canine/premolars, skin of chin
-buccal nerve: skin of cheek, lateral gingiva of lower molars

Question 280

SS_HN 1.20: Outline the types of facial, maxillary and mandibular fractures and their surgical management

Answer 280

Significance of facial fractures:
-Facial trauma may compromise airway & be ass’d w C-spine, head & dental injuries (along w other trauma)
-May bleed significantly (good blood supply, may be occult in unconscious pt (accumulating in airway, pharynx, stomach)

Upper third= frontal, sphenoid bones & upper half of naso-orbito-ethmoidal complex. contains eyes & most of the paranasal sinuses (frontal, ant/posterior ethmoidal, sphenoid). # may be ass’d w dural tears, CSF leak, risk ascending infection.
**care ++ w tubes needing to be placed into nose (foley catheters NGTs & temp probes- risk brain penetration)

Middle third (mid-face): maxilla, zygoma, lower half of naso-orbito-ethmoidal complex. contains eyes, nasal airway, maxillary sinuses, maxillary teeth. may result in airway compromise & significant haemorrhage.
immediate life saving measures= placement of rapid rhinos/bite blocks to splint maxilla & tamponade bleeding points. can be assd w other facial #s, neuromuscular injury & dental avulsions.
Le Fort classification: describes degrees of separation of mid face from skull base (pterygoid plates of sphenoid bone involved)
1= “floating palate”: horizontal maxillary fracture, teeth separated from upper face. passes through alveolar ridge, lateral nose & inf wall to maxillary sinus.
2= “floating maxilla”: pyramidal #, teeth @ the base of pyramid & nasofrontal suture @ apex. passes posterior alveolar ridge, lateral walls maxillary sinuses, inf orbital rim & nasal bones.
3= “floating face”: craniofacial dysjunction. passes nasofrontal suture, maxilla-frontal suture, orbital wall & zygomatic arch.

Lower third:
mandible & it’s teeth.
Often a # in 2+ places (hard to break a ring in only one place).
most mandibular #s don’t significantly impact the airway UNLESS there’s gross displacement (which —> large sublingual haematoma reproducing airway compromise sim to ludwig’s angina) OR bilateral anterior mandible #s causing tongue to fall back into oropharynx (conscious pts will sit up & forwards to protect airway, unconscious supine pt sans a/w protection–> fatal #)
-teeth may be displaced/loose/avulsed

location of facial #s:
alveolar
condylar
coronoid
ramus
angle
body
parasymphyseal/mental
symphysis

Surgical management of maxillary fractures involves fixation of unstable segments to stable structures. need to restore proper anatomic relationships (eg. mid face projection, dental occlusion, masticatory function). may need maxillomandibular fixation (temporary, to allow proper reduction & fixation of fracture segments), miniplates or external fixation.
mandibular fracture surgery may involve closed reduction & indirect skeletal fixation (eg. interdental wires, arch bars, splints) or open reduction & direct fixation (wires/plates/screws).
approach may be intraoral, retromandibular, submandibular, preauricular

Nondisplaced & most minimally displaced #s don’t generally require definitive repair, those warranting urgent evaluation & admission= nasoethmoid (CSF leaks & meningitis risk), zygomatic arch #s ass’d w trismus (risk airway complications), le fort need surgical repair. facial #s in pts w multiple sig injuries. tripod fractures (those involving zygoma, lateral orbit, maxilla) with ocular findings need urgent ophthalmologist evaluation.

Question 281

SS_HN 1.21: Discuss the anaesthetic management of patients requiring surgical fixation of facial, maxillary and mandibular fractures

Answer 281

Pre:
trauma? primary survey, addressing all life-threatening injuries:
ABC, careful airway assessment, remove blood & debris (eg. 2 suctions), Ax (trismus, soft tissue swelling, nasal obstruction (inability to breath through one side of nose suggests nasal fracture), bleeding)
if no c-spine injury, pts should be allowed to assume position of comfort. in alert pts with bleeding, control w external compression. If these manoeuvres aren’t sufficient to control bleeding & pt requires spinal immobilisation, may need intubation to protect airway, with large amounts of gauze in oro- or nasopharynx to gain control after intubation. If endotracheal intubation is indicated, anticipate difficulty in pts w heavy bleeding or evidence of haematoma extending into neck or supraclav region. pre-O2 in pt position of comfort, then intubate in optimal position (w MILS if indicated), double set-up (oral intubation +/- FOB & cricothyrotomy).
blind nasal intubation should be avoided esp in the field if facial trauma.
consider ass’d injuries esp related to mechanism:
-chest (eg. PTx)
-haemodynamic compromise; consider TxA if acute haemorrhage. surgeons may suture lacs or ligate relevant vessels (tissue ischaemia unlikely as extensive anastomoses among facial arteries). massive bleeding—> interventional radiology.
-CNS (pupillary size/reaction, GCS); injury to carotid vertebral arteries suggested by expanding haematoma, lateralising neuro injuries. There may be cerebrovascular injury risk esp w Lefort II & III. incr risk intracranial injuries if on anticoagulants.
-BOS # (blood or fluid from ears or nose (eg. “halo sign”, blood w CSF halo- glucose usual screening for CSF detection), raccoon eyes, battle sign (bruising over mastoid), visual/hearing/smell changes, defects in eye movements, loss of balance, weakness of facial muscles, C-spine injury, carotid or vertebral artery injury, lower cranial nerve damage. BOS # contraindicates nasal intubation.
-review pre-op imaging

-facial examination forms part of secondary survey:
Hx: ability to breathe through both nostrils (nasal fracture), difficulty speaking (trismus suggests mandibular fracture), diplopia/visual disturbance (more common with orbital fractures or nasoorbitoethmoid fractures. hearing? facial numbness? (eg. with zygomatic fracture, pt may have injury to infraorbital nerve). Prev facial injuries, surgeries, ocular procedures to correct vision? (incr risk for ocular injuries & possible globe rupture), do your teeth come together the way they did? any teeth painful/loose? bleeding nose/ears/mouth? vertigo (suspicion for temporal bone #), loss of smell (may suggest damage to cribriform plate, often ass’d w CSF leak; if CSF leak, elevate head of bed 40-60 degrees to reduce ICP (decreases art inflow, incr venous outflow & allows leak to seal).
exam: observe for asymmetry, orbital # may cause exophthalmos, enophthalmos, EOM entrapment, hyposthenia. haematoma forming in the orbit may cause compression of retinal artery & require emergency lateral canthotomy.
other findings w naso-orbito-ethmoid injury: diplopia, nasal congestion/epistaxis, vision abnormalities, dizziness, anosmia
palpate for focal tenderness/crepitus/motion
motor (VII) & sensory (V1/2/3); anaesthesia of area supplied by infraorbital n (ipsilat lower eyelid, lateral nose, upper lip, ant maxilla) suggests orbital floor #, may also have periorbital ecchymoses or be unable to look up (entrapment of inf rectus)
eye VA & EOMov’ts
Dysphonia or oedema of oropharynx suggests significant haematoma or # (incr risk airway compromise); stridor or drooling suggests airway difficulty; secure airway early if risk of obstruction
Battle sign suggests basilar skull # but doesn’t develop until 2+ days following trauma.

Ix: depends on haemodynamic stability, cooperation, resources.
Facial bone # visualisation best achieved with HRCT. CT angiography useful if expanding facial haematoma or injury to carotid artery.
Plain XR useful for screening minor trauma only (lack sensitivity for many bony & soft tissue injuries).
Ocular & orbital injury suspected: bedside US. can detect vitreous haemorrhage, retinal detachment, globe rupture BUT if suspect globe injuries, CT imaging & emergent ophthalmologist consult.

Intra:
BMV may be compromised by incr jaw movement/swelling/bleeding
consider 2x large-bore suctions
Intubation: trismus tends to relax following induction in trauma (distinct from due to infection) but may persist due to mechanical reasons (d/w surgical team); bilateral mandibular #s allow incr ant jaw displacement.

tube selection:
zygomatic or orbital fractures: south facing oral RAE
mandibular, LeFort fractures involving malocclusion: nasal

If marked swelling or mechanical impairment to jaw opening, AFOI may be required. Usually RSI appropriate (eg. pt may be combative/agitated; 2-peron technique if anticipated difficult airway, w double set-up (scrubbed ready for FONA). Inhalational induction often difficult (pain with facemask, blood, agitation)
Alternatives to oral: tracheostomy, submental intubation

Other considerations:
throat packs
mandibular fracture positioning prior to induction/intubation?
facial nerve monitoring
steroids to reduce swelling
suction
analgesia
Abx prophylaxis in wounds w gross contamination (eg. some bites), orally penetrating wounds, exposed cartilage, devascularised wounds, wounds ass’d w open #s. Tetanus prophylaxis.

Postop:
planning time of extubation: oedema can worsen in the 48hrs after injury (for lefort II & III); if extubating, ensure leak test passed, consider AEC, do w pt fully awake w smooth emergence & extubation, minimal cough/strain to limit bleeding (antihypertensive/anti-emetic/anti-SNS techniques), care w facemask position (plates/screws). can consider withdrawing nasal tube & cutting to leave as a NP airway. wire cutters or scissors for elastic band fixation should be w the pt @ all times. surgeon must be present until successful extubation.
PROLONGED PACU stay & consideration of HDU overnight (low threashold ++ to keep intubated if ANY obstructive symptoms preior, oedema tends to worsen postop!)
appropriate analgesia/anti-emetics. consider need for IVT (should have PO fluid asap). some pts may need HDU post-op for close observation or remain I&V.

Question 282

SS_HN 1.5: Describe the common co-morbid disease and patient factors encountered in patients having head, neck and ear nose and throat procedures

Answer 282

Either young/fit or unhealthy (esp smoking-related lung disease, ETOH abuse)/elderly/Ca pts, OSA & obesity & pathologies related to unmanaged OSA (pulm HTN, RHF) common. if Ca, may be cachectic/frail/malnourished.
may be children or intellectually disabled who have ingested foreign bodies

the pathology may produce airway obstruction & make access difficult/impossible; utilise thorough multi-D assessment incl imaging, FNE, Hx/exam
Shared airway, often remote from pt & their airway

Question 283

SS_HN 1.7: Discuss the surgical requirements and the anaesthetic management of patients requiring common elective ear nose and throat procedures including

& SS_HN 1.17: Discuss the clinical features and management of postoperative haemorrhage following head and neck and ear nose and throat surgery, particularly post tonsillectomy haemorrhage (also refer to the Airway management and Resuscitation, trauma and crisis management clinical fundamentals and the Paediatric anaesthesia specialised study unit)

Answer 283

septo-rhinoplasty see rhinological surgery

-TONSILLECTOMY/ADENOIDECTOMY paeds:

common procedure that involves a shared airway & application of a boyle-davis gag which might obstruct airway

Pt: young, may be systemically well or recurrent URTI/LRTI (timing of OT)
OSA/sleep-disordered breathing- impacts induction/airway plan, extubation & post-op (risk airway obstruction)
disposition/monitoring

Pathology:
risks airway obstruction, OSA/sleep-disordered breathing (likely OPA useful esp w pre-O2)

Procedure:
usually short (20-30mins), painful, minimal intra-op bleeding but risk postop bleed
shared airway (limited access, risks occlusion w Boyle-Davis gag (ensure adequately deep, watch airway pressures), dislodgement of airway, pressure to surrounding structures, must protect from blood & secretions, incr risk broncho/laryngospasm, excellent communication with surgeons of utmost importance

Potential complications:
airway obstruction (boyle-davis gag)
PRAEs if proximate to an URTI/LRTI; airway hyper-reactivity risks broncho/laryngospasm, risk decreases over time after URTI (delay 4/52); Pre-op SABA, anti-sialogogue glyco 4microg/kg, nasal decongestant. Vent strategy: lower MV, low PEEP, adequate E time so flows to baseline, intermittent disconnection may help if high Pit. experienced operator. Post-op incentive spirometry, chest physio.
peri-op airway obstruction (particularly w post-op opioids, long-acting sedative/hypnotics)
bleeding risk (post-tonsillectomy haemorrhage risk 0.5-2%)0 return precautions 9important
post-op airway compromise particularly w use of opioids if OSA

Anaesthetic considerations:
pre:
ideally avoid sedative premed (risks airway obstruction, BZD delays wakening, prolongs excitatory phase of emergence, impairs pulm mechanics & risks post-op pulm complications)
paediatric- communication/rapport w parent, child

intra:

Prepare:
-all equip (less anx for parent/child)
Ideally IV induction (use emla)- (if gas, insert IV asap)
M: SpO2 only for induction then other monitoring on when deep
Equip: have appropriate size south-facing RAE, size up & down, SGA, suction, guedel, NPA
Induction:
smooth, atraumatic induction

Maintenance: Propofol vs sevo= less impairment of ciliary clearance of bronchial/tracheal secretions, APRICOT study: inhalation induction ass’d w sig higher risk severe resp events
-use sufficiently large induction dose & NMBD
-intubate without m relaxant esp younger chn (avoid in child <10 who weighs <50kg undergoing tonsillectomy unless RSI)
-cuffed ETT (protect airway from blood/secretions/fire risk w electrocautery); oral RAE or reinforced, in the midline & taped to jaw before gag (*watch tube carefully as gag set up, ensure pt sufficiently deep prior to mouth gag placement, watch airway pressures
-airway protection (from blood/secretions) during shared airway procedure- cuffed ETT (SOUTH-FACING RAE) good protection & seal reduces risk of O2 leak/airway fire, less OT pollution from volatile, better surgical conditions, also ETT better for use w Boyle-Davis
-meticulous positioning (supine w neck extended, shoulder roll, care w tube position)
-adequate post-op analgesia (sore, post-op pain for up to 2/52); multimodal (paracetamol, dex, opioids w dose reduced 50% if child has OSA, lowest effective dose of short-acting opioids, often no NSAID (bleeding risk))
-PONV prevention (multi-modal anti-emetics); risk PONV 60-70% in chn undergoing tonsillectomy who don’t get proph anti-emetics

Emergence:
-smooth, rapid emergence to allow recovery of airway protective reflexes, avoid airway obstruction & resp depression
-thorough suction under DIRECT VISION prior to extubating (turn sucker northwards & suction “coroner’s clot” for ANY nasopharyngeal or procedures using nasal tube), awake w ability to protect own airway (& can suction stomach w OGT to empty it of blood for bleeding tonsil)- ensure not btwn deep & light, recover pt in lateral recovery post w neck sl extended (“tonsil position”), allow secretions to drain away from oropharynx, w guedel, keep pt in tonsil position until airway reflexes return (need skilled PACU staff, be immediately available)

IV stays in (postop bleeding risk)

Postop: regular & prn analgesia (NSAIDs not shown to incr bleeding risk),
disposition: NOT day case if <3yo, co-morbidities eg. NM disorders, DS or airway anomalies, Hx mod/severe OSA- if day case, 6hr postop observation

adenoids shorter, less pain, may be done w LMA & usually don’t need post-op opioid

tonsil in adults same except usually more postop pain (add tramadol), use IPPV & relaxant, quinsy usually treated with ABx (if need drainage, usually aspirate pus w syringe under LA)& tonsillectomy later.

BLEEDING TONSIL:
this is a threatened airway in a patient w requiring an emergency shared airway procedure who requires resuscitation pre-induction
main concerns are his:
-haemorrhage shock and hypovolaemia- difficult to quantify, may become significantly haemo-dynamically unstable w induction (bleeding may be concealed as swallow- high index of suspicion for pt swallowing ++ in PACU)
-full stomach
-difficult intubation- blood & swelling if a/w
-anaemia

Call assistant (senior reg/other anaesthetist, skilled anaesthetic nurse) to prepare OT while I’m down w pt:
airway: size 7 cuffed south-facing RAE tube (& 6.5, 7.5), backup size 3 & 4 igel, difficult airway trolley
drugs: suxamethonium 60mg
ketamine 80mg
emergency drugs adrenaline 0.38mg (IM 0.5mL), atropine 7.72mg
resus: IV fluids bolus 380mL crystalloid ready, blood in PACU fridge (notify blood bank)
warm line, OT warmed, pt warmer ready
equipment

all ready for our arrival from ED- emergency drugs for transfer

focussed R/V esp prev charts (eg. if this OT was in this hospital- expect airway to go down a grade), allergies, med Hx & meds, last ate, events

Resus: I’d insert 2x 18g IVC (IO if difficult), immediately take off blood for abg, formal fbc, euc, group & hold & if large amount ongoing bleeding, rotem. I’d immediately commence aggressive fluid resuscitation enroute to OT. I’d call for 2 bags X-matched blood in PACU, cell-saver called, blood bank aware of pt

monitoring I’d use NIBP and have my reg ready for post-induction art line (unlikely time pre-op), assistant place BIS, NMT, 5-lead ecg, SpO2 probe

2x senior anaesthetists: one for airway, the other to manage resus, additional ENT surgeons (incl ready for FONA if enter vortex) & senior nurses

we’d have 2x large-bore suctions ready

Intra-op issues:
haemodynamic stability, difficult airway (obscuration w fresh blood, arterial bleed & oedematous VCs), aspiration risk incl blood in stomach, anaemia (DO2, desaturation risk)

MUST resuscitate before induce (improvement in HR- set targets)

pre-oxygenate L) lat decubitus, head down (drains blood away from airway)

Once surgeons scrubbed & ready, RSI w cricoid & 2 suctions ready & ?Andrew Donohue’s suction technique

Turn supine for RSI w cricoid
ketamine 1-2mg/kg, sux 1.5-2mg/kg, C-MAC (has good light even though likely blood gets on it)- likely to bmv while sux working as hard to perfectly pre-O2 anxious bleeding child

intra-op, haemodynamics, likely short & not painful, short-acting agents aims for rapid emergence & recovery of airway reflexes
place orogastric & empty stomach prior to extubation (blood highly emetogenic. extubate pt awake w airway reflexes, after thorough suction under direct view, L) lateral, fully reversed), risk desat on extubation (check ABG (Hb likely dilute w resus) etc prior to extubation)
FESS (see rhinological surgery above):

FESS:
shared airway procedure (+/- for a pt at elevated risk of periop cardiac adverse events)
main conflict I anticipate is that for a bloodless surgical field surgeons often prefer lower BP however it is critical that coronary perfusion is maintained
surgeons likely to use topical or injected vasoconstrictors (HTN/tacchy response may increase myocardial O2 demand, risk esp for pt w Hx IHD)
position: slight head elevation

Pt:
Pts presenting for rhinological surgery may have: OSA, asthma, CF
optimise modifiable risk factors eg. HTN
if OSA may have pulm HTN
if on CPAP ?can it be used after FESS?
meds

Procedure:
may be indicated for chronic sinusitis, nasal polyps, epsistaxis control, tumour excision
supine, head ring, head-up tilt position
not long (20-100mins), minimal blood loss but surgeons prefer bloodless field
shared airway limits access to a/w, potential for airway bleeding & post-op airway swell/obstruction, potential for displacement/obstruction/damage of pt or equipment. close communication vital.

Potential complications;
-haemorrhage which may compromise airway; topical TxA may reduce intra- & post-op blood loss, improve surgical field
-CSF leak & intracerebral infection/meningitis
-orbital/optic nerve trauma
-nasal vasoconstrictor (topical or infiltration) may—> significant HTN, incr O2 demand
-hypertensive/tachy response to topical VC; anticipate this (CLEAR communication w surgeons), if extreme HTN use alpha blocker prior to B. if surgeons use topical cocaine, max dose 2mg/kg. peak levels 30-60mins.
-complications of throat pack

Anaes considerations:

Prepare OT: south-facing oral RAE (better than reinforced LMA)
???throat pack NOT inserted by me, visual & written reminder

pre-O2 likely need guedel (blocked nose)
Induction: prop/remi
south-facing RAE
Maintenance prop/remi- excellent operating conditions for head & neck, smooth emergency
mod pain; remi & oxycodone (care if OSA- may consider fentanyl or half dosing foxy)
Emergence:
suction deep under direct vision (“coroner’s clot”)
load w anti-emetics
inclined head up for emergence, aim for coughless extubation (utilise remifentanil, ensure good volumes & breathing on command prior to extubatne)

Recovery:
sit pt up to reduce bleeding, may incorporate NPA into nasal pack to assist pt comfort
analgesia: rapid-acting
ongoing multi-modal anti-emetics
keep warm, likely standard ward unless significant comorbidity
IV in overnight (bleeding risk)

MICROLARYNGOSCOPY:
Examining larynx, excision/biopsy, may use laser
short (10-30mins) stimulating procedure
shared airway
want an awake pt at the end w minimal coughing
pt often multicomorbid (esp smoking)

Pt: often smoker, multi-comorbid (eg. malignant lesions, pulmonary & cardiovascular disease common)
may be @ risk for airway obstruction (careful airway Ax, FNE, plain films/CT.

Procedure:
examination of larynx, short, shared airway (ie. surgeons at the airway, access may be limited), stimulating when gag placed
DISCUSS with surgeons what they are planning to do-
depending on what surgeons doing (eg. ignition source w laser?), may be risk airway fire

discuss w surgeons if they want wrt airway:

-if they need to visualise laryngeal function (uncommon), must be S/V; high-flow & TIVA allows uninterrupted surgical access, unprotected airway. laser may be used (w blender). can achieve prolonged apnoeic oxygenation w HFNC. may be preferred to resect posterior lesion.

microlaryngoscopy tube w IPPV
-small ETTs allow better surgical access but only ant 2/3 of glottis. conventional IPPV & monitoring gas exchange & airway pressures. protects against aspiration of blood/surgical debris. measured inflation pressures will be high but Paw distal to tube will be lower.

-TIVA & jet ventilation using injector system (O2 + entrained air, preferred if laser used) via either: injector needle in operating laryngoscope (sanders technique, O2 & entrained air), tracheal catheter or cricothyroidotomy needle/cannula. I’d induce & use LMA or microlary tube initially, then when surgical team ready for laser, jet ventilation. Have anaes machine close by for FMV at induciton/recovery. minimal pressure to produce chest expansion- pt relaxed, hand on diaphragm to Ax. CLEAR communication w surgeons paramount. at end of case, alternative airway until S/V re-established.

POTENTIAL COMPLICATIONS:
airway obstruction: have rigid bronch available
laryngospasm
airway fire/burns
VAE
PTx, subcut emphysema, PTx, pneumometiastinum,, barotrauma & difficulty maintaining oxygenation in morbid obesity or stiff thorax (hypoxaemia or hypercarbia)
gastric distension
aspiration risk (I generally don’t use topical LA0 reduces risk laryngospasm but impairs airway protection)
if airway unsecured, risk spread of particulate matter w tracheobronchial viral or tumor seeding- N95 for all, eye protection, fire safety equip, difficult airway equipment, cricothyroidotocmyy kit, surgeon prepared for emergency tracheostomy or rigid bronch

anaesthetic:
PREPARE:
size 4, 5 or 6 (“paediatric size, adult length”)
have saline ready (risk airway fire)- 50mL syringe prefilled
difficult airway trolley
IV 20g

pre-O2
TIVA (so don’t rely on tube for ventilation) AND remifentanil (since the procedure short & stimulating), muscle relaxation (short-acting agent)
microlary tube

Airway:
Breathing:
tube high airway resistance so higher pressures needed to ventilate & lower I:E ratios often required, spont breathing doesn’t work v well w MLT.
Low FiO2 during any laser/diathermy of the airway
risk poor oxygenation, atelectasis & shunt/desaturation during procedure

position supine w pad under sh, head extended

Postop risk stridor from oedema; dexamethasone 8mg to prevent, consider nebulised adrenaline. analgesia w paracetamol/NSAID.

PANENDOSCOPY:
Procedure:
short, stimulating
hyperextended position- risk vertebral artery dissection
laryngoscopy, bronchoscopy, esophagoscopy
SHARED AIRWAY
anaes goals= deliver O2 (closed system w microlary & cuffed ETT or open system (STRIVE-Hi, supraglottic JV, subglottic, trans-tracheal), remove CO2, anaesthetise, protect airway from soiling or aspiration
surgeon requires immobile field & time for Dx evaluation & intervention.
risk middle column bleed/swell when remove lesion, risk rupture/damage. risk damage to structures (eg/ oes rupture)
discuss. wsurgeions oxygenation: mlt, spont vent, jet vent

Patient:
may have critical airway obstruction; in these cases, elective trache under local prior to endoscopy safest.

GROMMETS:
PATIENT:
Paediatrics: communication w pt & parent
population often w recurrent URTIs; timing of surgery to limit risk PRAEs
generally day case

PROCEUDRE:
very quick (5-15mins)
myringotomy & grommet insertion, usually bilateral
shared airway/limited airway access
emetogenic +++

ANAESTHETIC:
careful Ax re: URTIs & OSA (often tonsillar/adenoid hyperplasia)
prefer IV induction for pts w recurrent URTIs; EMLA & premed to assist eg. dexmed 1-2microg/kg IN (but care if recent URTI or if OSA)
pt needs to be deep +++ as it’s very stimulating
BUT it’s short :)

often gas induction, IV asleep 22g, hold mask (guedel in, T-piece, ensure reservoir bag visible) ideally (LMA if needed but ideally not instrument airway)
supine, head tilted to side, head ring
no blood loss

***reflex brady occ seen as partial vagal innervation of TM

rapid onset/offset agents
disposition: decision re: day case
anti-emetics ++
unlikely to need additional postop analgesia

MYRINGOPLASTY/other middle ear OT:

shared airway/limited access to airway
highly emetogenic
need for bloodless field
facial nerve monitoring

Pt:
usually young/fit
?PONV risk

Procedure:
shared airway, limited access to pt
myringoplasty= recon perf TM w autograft (usually temporalis fascia), 60-90min, mod pain, supine, head tilt to side, head ring, head-up, minimal blood loss

stapedectomy/tympanoplasty= excision/recon of damaged middle ear structures, 2-4hrs, mod/high pain, supine head tilt to side & head-up tilt, head ring, minimal blood loss

Anaes:
Pre-op consider coexisting CVS disease (informs appropriate degree of hypotension)
premedication

goals:
avoid coughing
dry bloodless surgical field (more important for stapedectomy)

N2O avoided (may produce diffusion into middle ear & risk lifting graft off, particularly important for myringoplasty)
For tympanoplasty, depends if over or underlay graft. If overlay, avoid N2O as it may lift it off. if underlay, N2O may actually help graft settle against bony rim.

Prepare:
drugs: if NI monitoring, avoid NMBs

E: south-facing RAE or SMA (reinf)
M:
AVOID cough during OT & induction: LA spray larynx, monitor NMB
POTENT opioid pre-induction, avoid coughing (LA spray to larynx), head-up tilt, avoid HTN/tachy (MAP 60mmHg & HR <60bpm in HEALTHY pts *cognisant of perfusion pressure to brain; art line particularly useful for stapedectomy/tympanoplasty & CVS disease or if using potent VD), remi great (for stapedectomy/tympanoplasty art line often used), labetalol or B blocker + vasodilator.
anti-emetics!
*vertigo risk (prochlorperazine)?
care w positioning/pressure areas (limited access to face/head), particularly important to have secure airway

postop:
prn analgesics (paracetamol or NSAID)
anti-emetic REGULAR for 24-48hrs

MASTOIDECTOMY= clearance of cholesteatoma from mastoid cavity (chronic infection that may have caused a cholesteatoma which may become invasive into CNS)
90-120mins
mod pain, head-up tilt, head tilt to side on ring, minimal blood loss, RAE tube or LMA
bloodless field needed (prop/remi TCI)
if disease close to facial nerve, no relaxant may be requested

LARYNGECTOMY or PHARYNGOLARYNGECTOMY:

Patient:
-likely to have some degree of airway obstruction, look @ prev chart (likely to have prev anaes record from Dx) but airway grade may have changed if time has elapsed.
-likely smokers, CVS/resp issues, malnutrition (low protein may affect drug Pk)
-ensure pt aware of tracheostomy implications
consider Hx obstructive symptpms, thorough airway exam, Ix incl FNE, imaging plain film or CT to see extent of lesion, d/w surgeons mobility

Procedure:
SHARED AIRWAY: communication, access, pressure risks, airway implications (eg. swelling)
e/o larynx & creation of end-stomal tracheostomy
PROLONGED (3-4hrs)
Pain +++
Position: supine, pad under sh, head ring, head-up tilt

POTENTIAL COMPLICATIONS:
blood loss moderate (may be substantial); X-match 2 units
airway loss/obstruction (particularly during tube change to tracheostomy)
air emboli risk during dissection (watch EtCO2

Anaesthetic plan:
PREPARE:
-ICU bed booked.
-art line (discuss w surgeons their access (eg. they may want radial forearm free flap), temp probe IDC, consider CVC if multi-comorbid or anticipate particularly long/complex
-airway plans A/B/C (skilled anaesthetic nurse briefed), difficult airway trolley available, surgeon ready for emergency tracheosotomy if needed
-water in case airway fire
IV: large-bore x2 or one w CVC (FEMORAL)
Monitoring: art line, 5-lead, temp rpobe IDC< BIS, NMT
Equipment: diff airway as above
LONG tubing for breathing circuit & gas sampling tube
-pre-warm pt, FAWD & fluid warmer

Induction:
prop/remi, m relaxation
intubate w nasal tube or elective awake trache
insert fine-bore NG feeding tube @ induction (can suture to nasal septum)
MAIN RISK FOR AIRWAY= CHANGING TO TRACHE (reduce FiO2 during diathermy, just before change incr back to 100%, consider having a bougie placed if grade 3/4 view
Maintenance: care w pressure areas/position; head up MAP, pt likely malnourished. sh roll/head ring.
-if free flap, maintain yperdynamic circulation, MAP within 20% of baseline, Hb >=100 & Hct 30, TAPE vs tie, limit vasoconstrictors as 3rd line for MAP support

ABX PROPH @ LEAST 24HRS
long armoured tube via tracheostomy during surgery, change to standard @ end.

Postop:
HDU
humidification & regular suction
new trache causes coughing ++ (low-dose prop, morphine or BZD help.
multimodal analgesia (paracetamol & nSAID w prn morphine, IV/NG, surprisingly low analgesic requirements.
multi-modal anti-emesis.

If a pt w prev laryngectomy presents fur surgery, ventilate via stoma (paediatric face mask turned180 deg) or LMA applied to neck or intubate awake after LA to stoma (while tube insertion usually easy, check stoma for stenosis or tumour recurrence & always pre-oxygenate (I’d check w FOB after topicalisation & prior to intubation)

PAROTIDECTOMY:

PROCEDURE:
-e/o parotid gland, usually preserving facial nerve, temp probe IDC
2-5hrs, mod/severe pain
mall/mod blood loss; greater for malignancy, do hae G&S

PATIENT: most common is benign (pleomorphic adenoma) which can grow very large, may be for malignancy (4M’s). if malignant, often locally invasive (***if so, may have impaired jaw opening; thorough airway Ax)

POTENTIAL COMPLICATIONS:
bleeding
facial nerve damage
pressure areas (2-5hrs)

Anaes plan:
Prepare personnel, OT & equipment:
large-bore IVC 18g-16g, full body warming, art line, NMT (if use NMB for induction, need complete reverse), BIS, 5-lead ecg

Induction: prop/remi, just induction NMBD, south-facing RAE

Maintenance: pressure areas (may be prolonged)
remi to prevent movement after reversed NMBD, also great to reduce blood loss (reduce pulse, CO

Emergence: limit cough by keeping remi going @ low rate, longer acting opioid 15-20ins before end OT
head up, treat HTN early (clonidine useful), load w anti-emetics & ensure comfortable (limit SNS stimulation)

Postop: painful; multimodal, anti-emetics, monitor haemodynamics (consider degree of blood loss, ongoing limitation of HTN (limit neck haematoma)

NECK DISSECTION:

Patient: often multi-comorbid (elderly, smoking, IHD, PVD, DM, COPD, Ca & 4M’s)
airway assessment, previous grades, how may radiotherapy or pathology impact airway
nutritional (eg. alb)/functional status, frailty

Pathology:
metabolic, mass effets, mets; optimise
likely difficult airway (eg. head/neck tumour, prev major surgery or RTx)

Procedure factors:
May be ass’d w laryngectomy or other major procedure.
#shared airway- DEMANDS HIGH LEVEL CO-OPERATION BTWN SURG&ANAES TEAMS, MAY LIMIT PT ACCESS, attention to protect eyes/neck/teeth
bleeding risk- may be mod-substantial. X-match 2-4 units. head up position, TIVA. NOT hypotensive anaesthesia, I ONLY lower pt’s BP within 20% of normal, wouldn’t lower beyond their range of auto-regulation (risk organ ischaemia)
prolonged, 2-4hrs (fatigue of surg/anaes/team)
may be e/o SCM, int/ext jugulars & LNs (selective may preserve some of these structures esp IJV)
supine, pad under shoulders, head on ring side tilt

Anaesthetic factors:
our aims for shared airway surgery= unobstructed motionless operative field, oxygenation, CO2 elimination, adequate anaesthesia, rapid return of consciousness & airway reflexes after surgery

airway assessment/plan (must include evaluation of location, extent, size & mobility of lesion, effects on laryngeal function & airway patency, changes in size of lesions, cross-sectional imaging helps define upper & lower limits of lesions, nasendoscopy provides warning re: appearance of lesions)
pressure care
fatigue/staffing management

Potential complications:
-neck oedema- paritcularly worse if prev neck dissection on other side. Dexamethasone 8mg preop then 4mg IV 6-hourly may help
-damage to blood vessels, nerves (RLN, phrenic), muscles, thyroid/parathyroids
-carotid stimulation & haemodynamic instability (surgeons stop stimulus, LA into carotid body, depending on severity- compressions or glycop/atropine may help)
-PTx
-air embolus during dissection (watch CO2)
-pressure areas, risk of pt injury from inadvertent leaning on eyes etc
-periop MI
-Pain often not significant
-Blood loss may be mod-substantial

Anaes plan:

Prepare:
HDU bed
airway plans a/b/c w anaes nurse briefed, difficult airway equipment avail incl ENT surgeon ready for FONA if high risk (may plan elective trache)
IV: large-bore 16g, CVC femoral is best (AVOID remaining jugulars, HEAD&NECK VENOUS DRAINAGE DEPENDENT ON THEM!)
Monitoring:
temp probe IDC, BIS, NMT, 5-lead, art line
Equipment: diff airway as above (primary airway either north-facing (nsall tube or oral reinforced, taped) or south Rae secured on opposite side (not my preference as hard to fix)

Maintenance: remi ideal (assists bloodless field, rapid titration for stimulating parts)
pressure areas, proph ABx, IVT, warming, cognisant of occult blood loss.

Emergence:
depending on duration & pt/surg factors, may go to ICU intubated
otherwise coughless extubation, pre-load w multi-modal anti-emetics, analgesia to help control SNS/hypertensive response (clonidine useful, treat any HTN early)
consideration for risk of extubation (eg. cuff leak test, AEC left in); likely head & neck oedema for several days (impaired venous drainage) SO very likely to send intubated to ICU.
keep head up, avoid excess IVT.

TRACHEOSTOMY:

Procedure:
moderate pain, blood loss normally small (risk bleeding from thyroid vessels)
often for long-term ICU ventilation or airway obstruction
consider appropriateness of GA vs awake under LA (not difficult if dyspnoeic pt)
cricothyroidotomy preferred for emergency airway access (more acessible, less likely to bleed)

Potential complications:

Immediate:
-skin incision & tube exchange (changing & inserting trache, during transport & on return to ward) are hazardous times w risk loss of airway
-Airway fire (during electrocautery, reduce FiO2 down to 0.3, then before actual exchange, 100%)
-O2 desat
-haemorrhage- most common & most commonly fatal complication: approach= secure airway from above, ensure cuff of ETT below the stoma, then surgical exploration.
-aspiration
-air embolism
-failure
-damage to tracheal rings or other structures (RLN, oesophagus)

intermediate:
-delayed haemorrhage (eg. infective erosion into blood vessels)
-tube displacement (if need to replace tracheostomy tube, avoid multiple attempts which may risk surgical emphysema & swelling & this may make laryngoscopy impossible. consider establishing the airway from above early vs late, PARTICULARLY for new trache).
-surgical emphysema (eg. false passage of tube into pretracheal tissues)
pneumomediastinum
PTx ( so need post-trache CXR)
tracheo-oes or trachea-arterial fistula
-dysphagia
-infection
-necrosis (@ cuff)

delayed:
-stenosis if tracheostomy too high, if too low risk erosion into Tx inlet great vessels. ideal site is between 2nd & 3rd tracheal rings. stenosis may be @ stoma or in trachea (mucosal necrosis, fibrosis)- low-pressure high-vol cuffs reduce incidence stenosis
-decannulation issues (eg. if VC paralysis)
-tracheo-cutaneous fistula (eg. granulomas)
-scar issues

-obstruction @ any time

-stomal recurrence
-poor healing after RTx
-incr risk resp tract infections (loss of humidification & filtration from nasal mucosa, risk of mucus accumulating in redundant area above trachea & below larynx & it may fall back into lungs, causing local inflammation)
-tracheal mucosal keratinisation, pt discomfort, incr secretions if cold unfiltered air

-coughing/irritating new tracheostomy: manage w humidified O2, neb 4% lignocaine, judicious opiate use

(relative contraindications to perc trache= age <12, significant gas exchange probs, moderate coagulopathy, morbid obesity/short neck, suspected C-spine injury, limited neck ROM, aberrant blood vessels, thyroid or tracheal pathology, evidence infection over the site. Elective perc tracheostomy should always use fiberoptic bronchoscopy).

Anaes plan:
Pre-op:
want to know:
-how easy is intubation from above likely to be (prev airway grade, any airway complications since)? how easy is anatomy for the tracheostomy placement likely to be? WHY is this case for OT vs for a perc tracheostomy in ICU (anticipate it must be due to anatomical complications/obesity)? if elective, MUST be in-hours when pt & staff rested & all personnel (incl ENT) available.
-how may other pulmonary, cardiovascular or other general co-morbidities impact anaesthetic & SAFETY TO TRANSFER FROM ICU TO OT? eg. if on 20 & 20 Adr, NAdr or 100% O2, unsafe to proceed w transfer to OT & elective surgical tracheostomy as the pt would not cope w the reduction in FiO2 for diathermy.

Assess:
ABCDE for ALL ICU pts
Previous airway grades, current ETT size & how long been in, problems with the tube & has it needed to be exchanged?
ventilatory function (P:F), whether setting have needed to be changed, latest gas (w A-a gradient)
coagulation status
other co-morbidities (incl what lines/access & meds been on- inotropes or vasopressors, sedation, ABC)
ensure NG feeds stopped in appropriate time

Prepare: for safe OT transfer as per college guidelines (along w drugs & monitoring & ventilator)

difficult airway trolley in OT, surgeon ready for emergency trach if required.
infusions (inotropes, vasopressors)
GA agent (propofol TIVA), m relaxant, analgesia (likely large fent)

Prior to commencing, ENSURE THE CONNECTOR FOR MY ANAES CIRCUIT FITS WITH WHAT THE SURGEONS HAVE FOR THE TRACHE, ensure correct tracheostomy tube & sterile catheter mount

Pt positioned w shoulder roll, exposing neck to optimise success, head ring, head-up tilt

aspirate NGT & clear oropharynx of secretions

Induce, m relaxant, analgesia (keep the pt going on the infusions they have, can supplement w VA)
laryngoscopy before start to gauge roughly airway grade
ensure ETT is secured but in a manner to be easily exchanged, going “north”
drape to allow access

FiO2 down for diathermy (eg. 30%), cuff down

Just before tube exchange, FiO2 100% for 3-4 mins & ensure NMB adequate

If prev difficult airway, can put a bougie down the tube just as surgeons ask me to withdraw tube

Close communication w surgeon re: withdrawing ETT (2 people, 1 to deflate cuff & withdraw on surgeon’s instruction, one to pass circuit & confirm vent)

ETT not removed from trachea until tracheostomy secure & certain, capnograph confirmed w adequate volumes/pressures for new tracheostomy connection
If any doubt, can check position w FOB (eg. concern re: false passage)

Postop:
To ICU, careful monitoring for complications post trache
regular suction (blood, secretions
humidify inspired gas
multimodalanalgesia in recovery, little need thereafter
morphine, BZD or low-dose props for cough w new trache
ante-emetic prn
pt needs valved device for phonation

Question 284

AT_AM 1.7: Discuss airway management for patients with a tracheostomy

Answer 284

indicated for:
-upper airway obstruction (eg. swelling from burns, anaphylaxis, trauma, infection, facial trauma)
-prolonged ventilation (less anatomical dead-space which reduces WoB & assists weaning from mech vent, more secure than if ETT; that said, no strong evidence for reduced vent-ass’d pneumonia, hospital LoS, ICU days, Abs use or mortality if early vs late trache)
-bronchial toilet (tracheostomy more effective, eg. if excessive tracheo-bronchial secretions & need repeated suction such as neurological conditions w impaired cough/swallow)
-Planned surgical tracheostomy also indicated if there’s anticipated swelling & oedema which could—> airway compromise, poor resp reserve & difficulty rescuing the airway post (ie. a trace can be “at risk” extubation plan (as per DAS guidelines, either delayed extubation or planed trache)

3 parts:
1. outer cannula w flange
2. inner cannula (has a lock to stop it being coughed out, it’s removed for cleaning, benefits= can easily remove if obstruction w clots/secretions but it incr WoB, lengthens weaning (smaller ID); generally use dual lumen UNLESS obese or local swelling & require adjustable flange or if require flexible tube based on their anatomy/risk of abrasion/obstruction w rigid tube)
3. obturator (for inserting tracheostomy tube, fits inside the tube to provide a smooth surface guiding the trache tube insertion).
-may have a cuff (allows mech vent, lowers aspiration risk). If ventilating, inflate cough just enough to allow minimal air leak. deflate cuff if pt using speaking valve.
-fenestrated cuffed trache tube; for pts unable to tolerate a speaking valve- the fenestrations incr risk granuloma formation @ site of fenestration, higher risk aspirating secretions, may be difficult to adequately ventilate the pt.
-size based on internal diameter- of the outer tube if single lumen, inner tube if double lumen
-Traches w inner tube should be changed every 7-14 days, freq decreasing as stoma becomes better formed & pulm secretions decrease
-first tracheostomy’s change shouldn’t not occur within 72 hrs of trache being sited, ideally not within 7 days for perc trachea, allows formation of more reliable “track”
-low threshold for suspicion of erroneous placement if difficult to ventilate; if in doubt, re-intubate w oral ETT may be required.
-inhaled O2 must be humidified, cold unfiltered air is irritant, risks trache tube blocking
-pt should be fed enterally initially, oral after swallow Ax

Question 285

emergency Mx of displaced or blocked tracheostomy tube

Answer 285

this complication can be fatal

NAP4: displaced tracheostomy= greatest cause of major morbidity & mortality in ICU, obese pts @ particular risk of adverse events & adverse outcome. ALL pts in ICU should have an emergency re-intubation plan.

***** emergency bedhead signs should be placed with each pt, w info about their airway & guiding responders to check & manage potential problems easiest to fix & most likely to resolve emergency

emergency situation- ABC approach (focus on oxygenating the pt, securing airway, most likely from above particularly if pt deteriorating *****; IF LARYNGOSTOMA, there’s NOT access from upper airway, these are very secure airways even from within the first day, generally ENT should deal with these but if we assist, main issue likely bleeding so make sure use small tube. NOBODY should be in hospital without a card to remind what the pt has & their emergency algorithm. main difference trache/laryngostoma= trache can access airway from above. both look/listen/feel, see if pt is breathing for themselves, see if we can ventilate them, try to pass suction catheter)

if suspect tracheostomy displaced (eg. hypoxia, failure to achieve set pressure/ventilation, pt talking despite trache cuff inflated, audible cuff leak despite adequate cuff pressures), look for bedhead emergency algorithm for that pt:

-call for help (make ENT aware, high risk of a false tract if re-attempt new perc trache, anaes nurse w difficult airway trolley), look/listen/feel at mouth & trache site.

((( attach water’s circuit (mapleson C):
-square capnography, chest moving & water’s circuit balloon movement w spont vent & no swelling/surg emphysema @ the neck w gentle breaths w water’s circuit suggests trache displacement unlikely (consider DDx eg. PTx, bronchospasm) )))
-if no, suggests trache problem.

-100% O2 high-flow to mouth & trache (if relatively new trache, focus on airway from above). remove any speaking valve & inner tube (some of them eg. Shiley need the inner cannula in place to be able to ventilate through trache).
re-assess breathing.

-pass suction catheter if its an established trache or a laryngostoma (re-Ax), deflate & re-inflate cuff (in case it herniated over end of trache), re-Ax

-fibreoptic inspection for mature stoma (look for tracheal rings, carina, consider advancement of trache w GREAT care).

-*****if patient deteriorating @ ANY point & immediate troubleshooting hasn’t solved issue, deflate cuff & remove tracheostomy.
cover w sterile gauze & occlusive dressing, re-Ax
-ventilate w 100% O2 using ambu bag & facemask guedel, 2 hands on mask (cover stoma)- could use LMA
-if unsuccessful, ventilate the stoma w paediatric mask or LMA.

Options:
-induce (prop or ketamine & paralyse) & intubate from above w VL OR 2-hand technique w FOB, ensuring cuff below stoma
-intubate stoma w 6mm tracheal tube or tracheostomy (care ++++ if trache <7 days old)
using bronchoscope/AIC/bougie/AEC may help

once airway secure, ENT Ax/plan for surgical exploration/ reinsertion (a new per trache likely just collapsed, a surgical trache <7 days old should have ENT exploration to limit risk of false tract)

Question 286

Penetrating airway trauma

Answer 286

a trauma- may be associated other injuries (particularly C-spine, PTx, head injury risk)

uncertainty re: where & what disrupted (including vascular structures)- when instrument, risk extra damage/creating false tract or subcut emphysema so plan A MUST involve video-assisted

likely unfasted

Assess in ED (remote environment), safest location to secure airway depends on speed of evolution & stability/severity of pt condition

PT: may be agitated/ intoxicated
after deciding location, decision Awake vs asleep?
then, spont breathing vs RSI (pt likely unfasted)
Anaesthetic:
Plan: in ED or OT
Personnel:
-skilled anaesthetic assistant
-additional anaesthetist or senior registrar
-additional operator (ENT or ED Consultant/senior Reg) ready for front of neck access, ?cardiothoracics or ICU if chance need open chest or ECMO

Equipment:
-videolaryngoscope, fibreoptic, ETT ideally size 9 (?parker tip or reinforced if AFOI), CICO equipment
-if awake, local neb, MAD, spray as you go
- if asleep, ketamine/roc modified RSI (idelally cricoid if pathology doesn’t contraindicate
-planning 2-person technique plan A, plan B FONA

Question 287

SS_HN 1.8: Discuss the surgical requirements and the anaesthetic management of patients requiring emergency ear nose and throat procedures including:

& SS_HN 1.25: Describe the assessment and potential progression of dental sepsis and evaluate the anaesthetic management of patients with dental abscesses and Ludwig’s angina (also refer to the Airway management clinical fundamental)

Answer 287

REDUCTION OF FRACTURED NOSE:
PT: generally fit young pts following minor trauma but care re: other injuries (eg tooth, neck)
PROCEDURE: 1-15 mins, minimal pain, supine, if quick, preoxygenate & props only. If longer, oral RAE or reinforced LMA (provided meitculous suction & pull LMA awake) w throat pack (occasionally, particularly if long duration since fracture, may bleed ++, risking laryngospasm); discuss w surgeons procedure, bleeding risk, throat pack use

Anaes plan: pre-oxygenate well, IV access, IV induction, if RSI & ETT & throat pack, system to limit risk retained throat pack, meticulous suction of oropharynx

Post-op simple analgesia

SURGICAL Mx of OBSTRUCTING LARYNGEAL LESIONS:
Procedure: often laser, balloon dilatation OR larngectomy

Pre-op:
signs of obstruction, resp distress, ability to lie flat/tolerate secretions
comorbidities
exam: ardioresp, FNE, detailed airway Ax
Ix: CT
discussion w surgeon re: plan/shared airway/throat pack

Prepare:
brief skilled assistant & surgeon re: aiway plans a/b/c, difficult airway trolley w all equipment checked & avail, surgeon ready for FONA if needed

If obstruction–> narrowing of airway (stricture, papillomata) may be unable to insert ETT; best option= spont vent w suspension laryngoscopy

if obstruction is tongue/oropharynx, best optim may be AFOI but this isn’t possible if stenotic larynx

significant supraglottic lesion where would be difficult to maintain spont vent patency or pass scope: awake tracheostomy

postop airway plan & disposition depends on expected oedema/swelling, extent of OT. simple laser/balloon: wake & extubate
big procedure w anticipated swelling or trache: ICU asleep

DRAINAGE ORO-PHARYNGEAL CYSTS OR ABSCESS, INCL QUINSY:
Deep neck space infections most commonly from a septic focus of the mandibular teeth, tonsils, parotid gland, deep Cx LN, middle ear or sinuses
w ABx, deep cervical space infections relatively uncommon

The “danger” space provides a path for retropharyngeal infections to extend into the mediastinum.
Danger space is behind the retropharyngeal space, deep to both the superficial (investing) & middle (pretracheal) cervical fascia, the danger space is a potential space between the 2 layers of deep (prevertebral) fascia

other fascial spaces btwn these planes of the deep cervical fascia with potential for deep neck infections include:
-submandibular:
–> LUDWIG ANGINA: bilateral infection in submandibular, sublingual & submental spaces, begins in the floor of mouth, usually related to 2nd or 3rd mandibular molars. polymicrobial. rapidly spreading “woody” or brawny cellulitis without lymphadenopathy, protrusion of tongue.
fever, malaise, stiff neck, drooling, dysphagia, may lean forward to maximise airway diameter, muffled voice.
neck may be tender, may have palpable crepitus (“bull neck”), may hold mouth open w lingual swelling. generallly no lymphadenopathy. if spread to parapharyngeal space, trismus. inflammation may extend to epiglottis occasionally. comorbidities incl DM, HTN, HIV.
only do CT w IV contrast if pt stable enough; if urgent airway Mx, POCUS only if it doesn’t delay airway securement.
ABC; can usually manage airway w close observation & IV ABx but if swelling advances or dyspnoea occurs, immediate intubation, before stridor, cyanosis, asphyxia. best to secure airway in OT where possible, with DIFFICULT AIRWAY TROLLEY & EMERGENCY CRIC KIT w ENT READY.
AFOI via nasal route likely plan a) if pt tolerates
role of glucocorticoids unclear
empiric ABx
early surgical decompression to locate pus may only moderately improve the airway; abscesses develop relatively late, if pt not responding adequately to ABx, CT to look for an abscess to specifically drain under GA done, along w extraction of culprit tooth. CUFFED ETT.
significant complicaiotns= mediastinitis, carotid artery rupture, JV thrombosis, ARDS, pneumonia.

-parapharyngeal
-retropharyngeal (often have neck stiffness)
-prevertebral
-pretracheal
-peritonsillar space:
–>QUINSY: peritonsillar abscess = a suppurative complication of acute tonsillitis w extension into peritonsillar space. Mostly 15-30y-olds, high fever, odynophagia, unilat sore throat, otalgia. muffled “hot potato” voice, trismus, unilateral deviation of uvual towards unaffected side, soft palate fulness or oedema. may drool w airway compromise. Drainage, antimicrobial therapy & supportive care= cornerstones of Mx. hydrate & analgesia.
If limited trismus & cooperative adult, may be able to needle aspirate with topical anaesthesia, aware of complicaitons inc haemorrhage, pus aspirated into airway.
GA if unable to cooperate or if I&D (more painful, causes more bleeding).
May perform “quinsy tonsillectomy” if significant upper airway obstruction, other indications or if not resolving w drainage. Incr risk bleeding w quinsy tonsillectomy but minimises loss to follow-up & later procedure may be difficult due to fibrosis. obviously needs GA. controversial data re: glucocorticoids (insufficient evidence). significant complications= aspiration pneumonia, septicemia, IJ thrombosis, carotid artery rupture, mediastinitis.

Significant life-threatening complications include:
-parapharyngeal space: carotid sheath involvement w vacular erosion (eg. carotid artery mycotic aneurysm, CVA or shock/exsanguination, suppurative jugular thrombophlebitis)
-retropharyngeal may spread to mediastinum
-prevertebral may be associated with spinal epidural collections causing cord compression
-quinsy or ludwigs may both cause mediastinal spread, carotid artery or JV complications.
-infections are typically polymicrobial, resident flora of mucosal surfaces
-maxillary infections may–> orbital cellulitis, cavernous sinus thrombosis
-all risk sepsis

Evaluation:suspect deep neck space infection if:

unilateral sore throat, localised bulging (eg. pharyngeal wall/soft palate/.floor of oropharynx, neck pain/swell, torticollis, crepitus

signs of airway obstruction:
-muffled voice, drooling, stridor, resp distress:
–>ABC
–> intubate (awake/asleep, technique based on level of obstruction, airway Ax (eg. parapharyngeal infections may have trismuss ++ w induration/swelling below angle of mandible, systemic toxicity too (may need resus)pt tolerance)
–> short term high-dose croticosteroid if impending airway obstruction

Ix depending on stability:
-lateral radiograph may show expansion of prevertebral soft tissues if retropharyngeal abscess
-CT generally imaging of choice to define site & extent, MRI useful for extent of soft tissue involvement & vascular complictaion delineation BUT takes ages

Manage w antibiotics & surgical drainage of loculating infection. Removal of any dental source, open drainage for abscess but if well-defined without airway compromise, US-guided needle aspiration. if mediastinitis, generally thoracotomy indicated.

For Ludwigs, nasal AFOI generally best Mx.
FNE useful.
best in OT w ENT scrubbed & ready for FONA.

maintain w volatile or TIVA, multi-modal analgesia incl nerve block by surgeon, opioid
Decision to extubate is case-by-case; IF SIGNIFICANT SWELLING & STRIDOR AT PRESENTATION & NOT MUCH DRAINED, MAY BE NECESSARY TO KEEP SEDATED & VENTILATED UNTIL EXTUBATION SAFE. TUBE EXCHANGE MAY BE REQUESTED BY ICU, ONLY IF SAFE.
PTS W LUDWIG’S OR PARAPHARYNGEAL INVOLVEMENT WILL LIKELY DEVELOP FURTHER POST-OP SWELLING, EXTUBATION AS DANGEROUS AS INDUCTION, SHOULD FOLLOW DAS GUIDELINES w ALL AIRWAY EQUIP & DRUGS AVAILABLE, LEAK TEST, ENSURE PT FULLY AWAKE BEFORE EXTUBATE.

If doing an AFOI for abscess, once tube in have a look at DL.
If tube exchange requested, look again w video laryngoscope. symptoms prior: if threatened obstruction, even if drained a lot & steroid, I DON’T EXTUBATE. to ICU. if tube exchange, best in-hours w others around. consider pts stability in general. don’t do if pt/surg/anaes/facility factors make it unsafe.
FiO2 100% to pre-O2, re-paralyse, check epiglottis w fibreoptic (laryngoscopy view most useful)
HIGH THRESHOLD TO KEEP THESE PTS INTUBATED; these pts often get worse before they get better wrt swelling

Swivel-Y on nasal tube.
feed a Cook AEC down
videolaryngoscopy (standard MAC, D-blade hard to thread things)
pass bougie through cords (cuff of nasal tube deflated); consider maneouvreable bougie if difficult
railroad oral tube over bougie
move nasal tube up
feed oral tube in, bougie out, connect & once CO2, remove cook AEC & nasal tube

Question 288

SS_HN 1.25: Describe the assessment and potential progression of dental sepsis and evaluate the anaesthetic management of patients with dental abscesses and Ludwig’s angina (also refer to the Airway management clinical fundamental)

Answer 288

shared airway procedure
difficult airway: particularly does the patient have adequate mouth opening (trismus due to infection (vs traumatic) less likely to resolve w relaxant than w trauma- have a LOWER threshold for AFOI in infection)
is the expanding abscess impacting/distorting laryngeal anatomy (anterior column issue)
is the pt cooperative for awake vs asleep technique
is the pt septic w infection (need resus pre-induction)

PATIENT:
history- progression of symptoms
examining- mouth opening

PROCEDURE:
likely nasal tube
?can it be drained percutaneously?- an option if securing airway too dangerous

POTENTIAL COMPLICATIONS:
CICO
sepsis/haemodynamic instability
airway contamination

ANAESTHETIC PLAN:
prepare: difficult airway equip (plans A/B/C), monitors in place for ergonomics, bed turned so pt sitting on bed upright
personnel: Macs Facs scrubbed ready for CICO
skilled anaes nurse to pts L), other anaes to run sedation
AFOI setup parker reinforced tube 0.5-1 size down
carefully counsel pt
Sedation
topicalisation (lignocaine max 9mg/kg, may be harder to get good topicalisation w abscess/infection)
oxygenation
performance

Question 289

subglottic stenosis when suspect? how surgeons manage it?

Answer 289

exp stridor w b/g PHx multiple or long-term intubation
laser

Question 290

SS_HN 1.2: Describe the indications for and features of special tracheal tubes used in ear nose and throat surgery, for example those used for:
* Microlaryngeal surgery 

* Laser surgery
* Laryngectomy

Answer 290

Microlaryngoscopy:
-obstruct posterior third of glottis.
paediatric ID (4,5,6) but longer than tube of that diameter would usually be (the MLT is 31cm long, equivalent to adult size 7 length- adult size 8,8.5 & 9 are 33cm, while size 5 is 24cm.
high volume, low pressure cuff
size 5 but not size 4 accommodate an adult stylet.
-higher airflow resistance so may need higher driving pressures & lower I:E ratio, spent breathing doesn’t work well.
-NOT laser resistant (so lower FiO2 during any laser/diathermy)
-operative field relatively mobile
-low risk barotrauma, reliable airway pressure monitoring & gas monitoring, no gas entrainment

Laser:
-may choose to use a transglottic catheter (eg. hunker) for JV, which has a side port for monitoring CO2 and an introducer
-laser-resistant ETTs- may cover a PVC tube w metallic foil w outer non-reflective layer, but risks incomplete or some coming out in airway if magyvered
-PVC cuffs (not laser-resistant)- inflate distal first (saline), proximal w methylene blue.
-the laser-specific tubes have thick walls & smaller IDs, require high driving pressures, require a pre-loaded stylet, should remove before emergence to avoid discomfort (eg mallinckrodt laser flex (stainless steel w double cough), Xomed laser-shield II (aluminium wrap, silicone tube & cuff), sheridan red rubber tube wrapped w copper), red rubber wrapped w protective metal foil.
other options= no tube in airway, venturi jet ventilation (pt needs to be RELAXED, hand on diaphragm to minimise risk barotrauma, start w low pressures, incr & stop once chest wall moving)

Laryngectomy: short reinforced tubes, place directly into laryngectomy stoma. can use for volatile but leak may be an issue. secure to pts chest w tape or sutures (can fall out relatively easily).
lady tubes need to be discarded after 24hrs, removed & cleaned 2-3x/day.

Question 291

SS_HN 1.4: Describe the nature and biological effects of lasers commonly used in ear nose and throat

characteristics of laser radiation?
biological effects

dangers?

benefits of lasers?

what are some gas lasers? their colour?

solid lasers?

Answer 291

monochromicity
coherence
collimation

Biological effects:
electromechanical (pulsed lasers shock wave, mechanical impulse eg. stone lithotripsy
-Thermal effects: light absorbed in tissue, raises electrons to higher energy state raising heat energy which cauterises & separates tissue, allowing bloodless incisions
Photoablative effects: molecular disruption & ablation
photochemical: modifies enzyme systems

-corneal & lens injury (pt, staff)
-burns (eg. deep damage to healthy tissue, inadvertently hit wrong target
-laser ignition of combustible fuel (risk airway fire/blowtorch effect)
-inhalation of viral particle aerosol & smoke plume; smoke evacuators 99% effective if within 1cm of target, filtration masks are also recommended (down to 0.1micrometres)

good haemostasis
minimal periop oedema
rapid healing
minimal scar formation
surgical precision
preservation of normal tissues
great for reaching distant pathology without compromising the airway

Helium/neon: red
argon: glue-green (for coagulation vascular lesions)
CO2: invisible (most common, poor tissue penetration (0.2mm), poor haemostasis (often need topical epinephrine), used for superficial lesions)

ruby (red)
Nd:YAG invisible (neodymium-doped yttrium aluminium garnet: more tissue absorption, more tissue oedema, 1064nm wavelength, used in ophthal & cosmetics & since penetrates deeper can use for tumours)
KTP (green)- potassium titanyl phosphate, absorbed by Hb so good haemostasis, can cause deeper therma burn & greater tissue damage

glasses provided should be suited to the type of laser

Question 292

AT_AM 1.4: Discuss airway strategies and outline a management plan for patients with critical airway obstruction, for example epiglottitis or laryngeal trauma.

Answer 292

Critical airway obstruction:
main issues:
-where is it (supra, glottic, subglottic)

-lying flat, GA & instrumentation likely to worsen any obstruction
-anatomical distortion, secretions, blood may impede identification of laryngeal inlet (especially for supraglottic lesions)
-severe stenosis may make passage of tube difficult, in continuity of larynx/trachea may make blind intubation dangerous

-how critical?; where & when to secure airway (crack on vs stay & play vs head for home)

-for B & C, “holding measures” include:
-HFNO (decrease WoB & distress, improve airway patency, improve oxygenation)
-steroids (useful if oedema/inflammation, little direct evidence of benefit in adult obstruction but improve symptoms in croup & for post-extubation stridor in adults
-nebulsised adrenaline; 1-5mg nebulised in O2
-heliox (not widely available, limited O2 content in mixtures useful for flow characteristics

To help inform airway obstruction in general (would just use plain film for paeds or known FB as wold just need bronch anyway):
nasendoscopy
CT, can do 3D reconstructions but doesn’t provide info re dynamic or postural contribution
MRI= gold standard tissue imaging & limited by prolonged times & intolerance fo supine position

Awake or asleep?
awake FOB, videolaryngoscopy or tracheostomy
asleep spont breathing or RSI

Irrespective of the technique, have all equipment incl difficult airway trolley, different laryngoscopes & tubes in various sizes, cricothyroidotomy kit

Supraglottic lesions where anatomical orientation=main issue, AFOI under LA generally best; scope may block the airway for stenotic lesions of glottis/subglottis
In children, deep inhalation anaesthesia is the only realistic option, best with child sitting on parent’s lap, IV placed when deep. For epiglottis, distortion of epiglottis may make glottis recognition difficult- passing on chest & watching gas bubble helps.

Question 293

SS_HN 1.13: Discuss the implications of use of local anaesthetics and vasoconstrictive agents in head and neck surgery

Answer 293

Anticipate issues as part of pt Ax (eg. CV comorbidities)
phenylephrine, cocaine, Adr may have significant systemic uptake, profound HTN & arrhythmias
Requires close communication btwn surgeons & anaesthetist
anticipate; remi, propofol, B-blocker, GTN
then support MAP when they wear off
max dose cocaine 2mg/kg

Question 294

SS_HN 1.14: Evaluate the use, safety and methods of providing induced hypotension to minimise blood loss and improve surgical operating conditions during ear nose and throat, head and neck surgery (also refer to the Plastic, Reconstructive and burns surgery specialised study unit)

Answer 294

Benefit= optimises operating conditions, less bleeding in surgical field, for ENT, middle ear surgery, pituitary, aneurysms (procedures where vascular structures in confined space, improves visibiliity.
cons= risk impairing vital organ perfusion, particularly in pts w chronic HTN or pre-existing vascular disease (pt selection important); hypoT, AKI, MI/CVA/TIA risks
strategies include prop/remi, volatile, direct-acting vasodilators (SNP, GTN, hydralazine), B-blockers, alpha blockers
Typical goal for normotensive pts MAP 50-60mmHg BUT ‘d never lower MAP <20% of the pt’s baseline (risk if go beyond range of autoregulation)

prop TIVA superior surgical conditions vs VA

Question 295

SS_HN 1.16: Discuss the indications, method and implications for anaesthetic management of monitoring facial nerve function intraoperatively

Answer 295

parotid surgery
facial fractures
posterior fossa operations (eg. excision of acoustic neuromas, base of skull operations)
middle ear surgery
mastoidectomy

Intraop facial nerve monitoring can significantly reduce postop facial nerve injury (demonstrated for posterior fossa OT, parotid surgery)

EMG electrodes in orbicularis oculi & orbicularis oris (2 m groups to assure redundancy). ground electrode for muscle & remote ground for stimulation probe (ie. total 6 electrodes). Connect electrodes to facial nerve monitor.

During procedure, EMG response displayed/converted to audio signals- immediate feedback to surgeon.
avoid muscle relaxant (or give then reverse, use NM monitoring to ensure reversed)
prop/remi useful

Question 296

SS_HN 1.15: Evaluate methods for the smooth emergence and/or extubation of patients to minimise bleeding following ear nose and throat and head and neck procedures

Answer 296

Specific strategies may help limit bleeding/wound disruption (with of raised venous pressure or arterial pressure risks eg. haematoma, wound disruption in head/neck or ENT procedures)
other complications raised ICP, raised IOP, CVS changes

Pre:
smoking cessation, BP control, avoid OT if URTI/LRTI

Intra: prop/remi
propofol-based ass’d w lower incidence complications related to exaggerated airway reflexes

Emergence: suction while deep
keep remifentanil running low rate (attenuate hypertensive respones @extubation, reduces coughing, incr tube tolerance; balance benefits of cough suppression w sedation/resp depression (need to remind pt to breathe))

consider extubate while deep onto a SGA (may be useful for pts w asthma, smoking but need to pre-oxygenate, laryngoscopy & suction under direct vision, ensure pt deep enough (risk irritation/laryngospasm if too light), inappropriate for difficult airway or aspiration risk. Pt sat upright & left undisturbed to emerge from anaesthesia

lignocaine 1mg/kg 45secs prior to extubation; reduces coughing

deep extubation: reduced risk cough/buck/haemodynamic effects, offset y risk UAO or aspiration, inappropriate for difficult aspiration
only if experienced in this technique, [re-O2, spont breathing but need to be sufficiently deep (no response to direct-vision suction, no airway response to deflation tracheal cuff. after extubate, maintain airway patency w simple airway manoeuvres until pt fully awake.

Other:
adequate analgesia (limit SNS stimulation/hypertensive response)
consider clonidine, have anti-hypertensives on-hand

Question 297

SS_HN 1.22
Discuss the anaesthetic management of patients requiring maxillary and mandibular osteotomies

Answer 297

PROCEDURE:
SHARED AIRWAY; excellent communication throughout, team brief vital, discussion re: type of tube, throat packs, haemodynamic goals, topical/injected vasoconstrictors, Abs, disposition. Correcting facial symmetry= a fundamental goal of the surgery, surgeons will need to periodically undrape face & Ax relationship btwn lips & central facial structures. anaesthetic equipment shouldn’t necessarily distort these tissues.
Surgical realignment of facial skeleton
May be prolonged; 3-6hrs
moderate pain
supine, head-up tilt & head ring
blood loss variable, occasionally severe, should have G&S
Bone plated & often transiently stabilised by wiring maxilla & mandible together; rare for this to remain @ end of case (these pt need ICU & adequately trained staff + wire cutters/scissors (if elastic band fixation) w pt @ all times while “wired”)

PATIENT:
may have isolated jaw malformation or multiple craniofacial deformities as part of a syndrome
usually fit & healthy, late teens or early twenties.

Prepare:
-meticulous airway Ax incl checking nostril patency. Pt should have Hb & G&S pre-op.
-airway plans a/b/c w skilled anaesthetic assistant; nasal tube, TAPE no tie (it’s north-facing anyway, just ensure NO impediment to venous drainage)
-consider difficult airway trolley, if anticipated difficult intubation (eg. severe jaw deformity, REVISION orthographic surgery, severe TMJ pathology & limited MO which is unlikely to improve substantially post-induction), nasal AFOI may be plan A. options if nasal intubation impossible: retromolar (reinforced oral ETT behind posterior molars which still allows teeth to be brought into occlusion), submental (oral ETT through floor of mouth percutaneously; initially an oral ETT placed, then top of it & pilot passed through horizontal FoM incision), tracheostomy.
-IV access: 1x large-bore (16g) for induction; 2nd one to be placed asleep
-monitoring: art line (can do asleep), BIS, NMT, 5-lead, SpO2, temp probe IDC, pt warmers
-pre-warm
-have antihypertensives/potent analgesics ready to blunt the SNS/hypertensive response to stimulating parts (eg. jaw #); remi, prop, esmolol, phentolamine, hydralazine, even GTN
-Induction: prop/remi (remifentanil infusion as part of balanced anaesthetic may help control BP, reduce blood loss, transfusion rate & OT time, improve surgical conditions & assist with blunting stimulating parts of procedure & smooth rapid emergence)
-Maintenance: propofol TIVA w remi given high risk blood loss (head/neck surgery) & to blunt SNS response (stimulating parts= laryngoscopy/intubation, incision, (anticipate HTN w any vasoconstrictor application) jaw #, extubation)
-avoid HTN but maintain organ perfusion (MAP 60mmHg or above unless pts baseline >20% higher than this; degree of hypotension to be agreed on as part of team brief)
-STEROIDS to minimise swelling
-IV Abs
-monitor blood loss
-positioning meticulous (long procedure); slight head-up, ensure no impediment to venous drainage, ensure MAP sufficient, eye protection (shared airway precautions), ensure normothermic, watch UO, VTE prophylaxis (adequate hydration, limit fasting time, TEDS/SCDs)
-Emergence: anticipate to blunt haemodynamic/SNS/hypertensive response to extubation, avoid cough/strain/buck on tube; longer-acting analgesic 15-20mins before finish, keep remi running @ low [], suction under direct vision (south & north) while deep & r/o any throat pack, load w anti-emetics, consider anti-hypertensive (eg. clonidine), lignocaine IV 1-1.5mg/kg 1 min before extubate, consider spray to cords/larynx) upright, extubate when retained airway reflexes & awake, withdraw nasal tube (15cm mark @ nostril) & safety pin it; leave as a nasopharyngeal airway. ideally avoid tight face mask to protect plates/screws.
-Postop: keep warm, humidified O2, anti-emetics, comprehensive multi-modal analgesia w prn IR opioid dose range (low threshold for PCA, all oral analgesics to be in soluble form, surgeons may perform mandibular or maxillary n blocks), anti-emetics, consideration of pharmacologic VTE prophylaxis once haemostats assured, likely continue postop steroids (usually 24-48hrs, +/- prophy ABx)
-prescribe IV fluids but encourage oral route asap
*if temporary stabilising by wire maxilla to mandible (rare), need wire cutters or scissors w pt @ all times (post-op vomit or bleed could be fatal; pts in this situation or w significant other airway issues to ICU postop)

Question 298

SS_HN 1.23: Describe the indications for and method of managing the airway during maxillo-facial surgery with a nasal endotracheal tube

Answer 298

Indications:
-dental or maxillofacial or oropharyngeal procedures requiring unimpeded access to the oral cavity +/- necessity to check bite alignment (eg. mandibular reconstructive procedures or mandibular osteotomies)
-limited ++ mouth opening
-AFOI via nasal route for patients with significant C-spine pathology or unstable C-spine or limited +++ mouth opening (oral route not possible)
-intra-oral mass lesions or structural abnormalities, angioedema of the tongue

Absolute contraindications:
-suspected epiglottits
-midface instability, disruption of nasopharynx or roof of mouth
-coagulopathy
-suspected basilar skull fractures

Relative contraindictions/precautions:
-large nasal polyps
-suspected nasal FB
-recent nasal surgery
-history of frequent episodes of epistaxis
-prosthetic heart valves (incr risk bacteraemia during the insertion)

method for managing nasal tube:
-screen for contraindications/precautions (particularly anticoagulants, Hx epistaxis), check nostril patency, ask re: previous nasal trauma/procedures
-spray co-phenylcaine (4/nostril adult)
-nasal tube in warm water to soften
-after induction, advance ETT into posterior pharynx (angle along floor of nose)
-direct laryngoscopy- advance ETT to glottis under direct vision. often the tube goes posterior- assist with head lift or grasp ETT with Magill’s (proximal to cuff) to guide.

At end of procedure, careful laryngoscopy under direct vision north/sough & ensure any throat packs removed

Question 299

SS_HN 1.23: Describe the indications for and method of managing the airway during maxillo-facial surgery with a nasal endotracheal tube

Answer 299

Indications:
-dental or maxillofacial or oropharyngeal procedures requiring unimpeded access to the oral cavity +/- necessity to check bite alignment (eg. mandibular reconstructive procedures or mandibular osteotomies)
-limited ++ mouth opening
-AFOI via nasal route for patients with significant C-spine pathology or unstable C-spine or limited +++ mouth opening (oral route not possible)
-intra-oral mass lesions or structural abnormalities, angioedema of the tongue

Absolute contraindications:
-suspected epiglottits
-midface instability, disruption of nasopharynx or roof of mouth
-coagulopathy
-suspected basilar skull fractures
-head injury with elevated ICP
-recent nasal surgery

Relative contraindications/precautions:
-large nasal polyps
-suspected nasal FB
-recent nasal surgery
-history of frequent episodes of epistaxis
-prosthetic heart valves (incr risk bacteraemia during the insertion)
-very small children/infants/neonates

appropriate sizing is important; oversized nasal tubes risk trauma eg. epistaxis, turbinectomy, retropharyngeal dissection, nasal alae pressure sores or necrosis (hence shouldn’t pass beyond pre-formed curve of tube)

warming the tube, lubricants or vasoconstrictor help limit risk, as does proper sizing; generally for females, 6.5 & males 7, considering height (larger ID is longer) & that distance from nares to VCs significantly correlates w pt height. For MOST adults, NT intubation @ 26cm females, 28cm males (measured at the nares)–> adequate placement in most adults.; proximal cuff should ideally be >2cm below VCs as risk of upward/downward movement (risking extubation & carinal irritation/R) main bronchus intubation, respectively. there should be 4cm between tip of tube & carina, adult carina 12.5cm.
paediatric ETT depth (age/2) + 12 (oral ETT)
NASOTRACHEAL: ((age/2) + 15)
(adult, ETT approx 21cm at teeth female, 23cm males, cuff 1.5-2.5cm from cords, tip 4cm from carina)

method for managing nasal tube:
-screen for contraindications/precautions (particularly anticoagulants, Hx epistaxis), check nostril patency, ask re: previous nasal trauma/procedures
-spray co-phenylcaine (4/nostril adult, 5mg/spray)
-nasal tube in warm water to soften, lubricate
-after induction, advance ETT into posterior pharynx (angle along floor of nose, bevel turned towards nasal septum).
-direct laryngoscopy- advance ETT to glottis under direct vision. often the tube goes posterior- assist with head lift or grasp ETT with Magill’s (proximal to cuff) to guide.

At end of procedure, careful laryngoscopy under direct vision north/souh & ensure any throat packs removed

*if fibreoptic, aim below the inf turbinate, less likely damage middle concha or cribriform plate (fracture of cribriform plate may cause CSF leak, risk meningitis or brain abscess).

Question 300

SS_HN 1.24
Discuss the anaesthetic management of patients requiring dental procedures including those with:
 Intellectual impairment
 Disorders of haemostasis

Answer 300

INTELLECTUAL IMPAIRMENT:
pre-op/planning considerations
-there may be difficulty understanding the procedure, may be anxious
-collateral from carer may be required, often useful to phone the day before to build familiarity/rapport with carer & discuss considerations eg. appropriate comfort strategies & appropriateness of premeditation
-pre-anaesthetic area must have space to accommodate carers, wheelchairs/hoists
-additional time needs to be allocated to lists to account for assessment/transfer/recovery considerations
-consider if blood needs to be taken or assessments by other specialities (opportunistic)
-create the calmest, least stimulating environment possible, limit delays in transition through hospital process, limit fasting time
-pragmatic wrt ability to obtain Hx, examination & Ix with the pt
-written & verbal info important (may be various carers)

intra-op:
PREPARE theatre & environment
ensure premed given w appropriate timing, short-acting aiming for min/mod sedation (maintenance of own airway & ventilation
topical anaesthetic for IV
IVC ready, drugs (incl vasoconstrictor), nasal tube
carer to be present in anaesthetic bay +/- diversional therapists +/- other comfort measures as appropriate to the pt
induction:
depending on pt, IV w sedation or when deep w inhalation induction (may require extra hands for excitement phase if adult)
similarly, level of monitoring possible pre-induction depends on the pt

maintenance:
simple analgesia + LIA
care w pressure areas/positioning (eg. may have fixed flexion deformities, vulnerable to pressure injuries)

Emergence:
again, quiet low-noise environment
consider clonidine
ensure IV bandaged/protected
own room w full handover to PACU staff (incl cognition, anticipation of any challenging/aggressive behaviour, mobility, positioning advice)- carer in recovery area assists

DISORDERS OF HAEMOSTASIS:
Haemophilia A (deficiency factor VIII) & B (def factor IX): both X-linked recessive (A more common), pts don’t bleed more profusely but may have prolonged bleed & may have delayed bleeding (clot instability). C is XI & AD or AR.
vWD (AD or AR): TxA useful for minor bleeding DDAVP incr [] vWFAg & VIII in most who have quantitative defect of vWFAg (eg. type 1 & other types known responders)
Inherited pet disorders: consider perio pet transfusion, d/w haematology
startegies:
antifibrinolytics, local haemostats measures, medication management.
GENERALLY pts on VKAs (provided INR not supratherapeutic ie provided <3) & on aspirin can continue them, other antiplatelets pt-& procedure-specific

Question 301

IT_AM 1.2 Discuss the important features of history & examination that may identify a potentially difficult airway

Answer 301

Current Ax tools: low sensitivity (+ve in disease) & moderate specificity (-ve in health), low +++ prevalence so low PPV—> signs in combination more predictive

9 things to consider when determining appropriate airway Mx plan:

1. Hx difficult airway?
2. Altered cardioresp physiology?
3. Aspiration risk?
4. Impact of the surgery on airway?
5. Ease of BMV? *if serious consideration of difficulty w BMV, awake intubation should be pursued

5 RoCA independent predictors of difficult BMV: FFOES: BMI >26, facial hair, Age >55, edentulous, snoring

Other:

Mask seal issues (facial hair/blood/saliva/anatomical abnorms such as retrognathia, facial fractures/abscess/infection/swelling/haematoma/trauma)

Pregnancy

Emergency surgery

Snoring/OSA/stiff lungs (reduced compliance eg. laryngosapsm, ILD/pulmonary oedema, neck radiation)

If good seal & compliance, can get 50-100cmH2O with BMV

Things we can do to help: shave beard, dentures in

6. How easy to insert & ventilate with supraglottic airway?

Predictors:

Reduced mouth opening

Obstruction @ or below glottis

Distorted airway

Stiff neck or lungs

Good LMA: >=7mL/kg TV, no >15-20cmH2O leak pressure

7. How easy to intubate?

Predictors:

Combination of TMD (<6cm diff w conventional laryngoscopy), MP (1= can see all of hard & soft palate, uvula, tonsillar pillars, II= can see soft palate & uvula, III only soft palate & base uvula, IV only hard palate, Hx difficulty OR reduced MO (abnorm <3.7cm), obesity, lack trained assistant, reduced neck E

Look (facial shape, trauma, beard, large upper maxillary teeth)

Evaluate TMD, MO (3F=MO, 3F=mentum to hyoid, 2F=hyoid to thyroid)

MP

Obstruction

Neck ROM

Modified Cormack + Lehane: In optimised position/blade +/- laryngeal manipulation

1: full glottis

2: a: partial glottic obscuration

b: only posterior glottis seen

3: a: able to lift the epiglottis

b: unable to lift epiglottis

4: unable to see epiglottis

8. How easy to place infraglottic airway?

Surgery of neck

Haematoma

Obesity

Radiation

Trauma

US may assist at identifying:

-cricothyroid membrane

-subglottic diameter

-tracheal position

-gastric volume

-pharyngeal/laryngeal pathology

-ETT position

-diaphragm displacement for successful extubation/post-extubation stridor

9. How easy to extubate this patient?

Question 302

IT_AM 1.3
Outline preoperative fasting requirements and the common measures employed to decrease the risk of pulmonary aspiration

Answer 302

continued consumption of clear fluid, esp carb-rich, may improve gastric emptying & mitigate metabolic & psychological impact of fasting.

Adults:
clear fluids up to 2hrs (max 400mL, NOT jelly & drinks containing particles, soluble fibre or milk)

light solids 6hrs (impaired gastric emptying 8hrs, 8hrs from fatty foods)
chewing gum doesn’t increase acidity or volume of gastric fluid cf control but must discard prior to induction (aspiration risk)- don’t delay surgery if someone has had gum provided they didn’t swallow it
can take prescribed meds w a sip water within 2hrs
*presence of solids/particulate matter in stomach is what is relevant to anaes

Children up to 16yo: limiting fasting time improves periop experience for chn
clear fluids up to 1hr before (up to 3mL/kg/hr)
limited solids & nonhuman milk up to 6hrs
>6/12 formula or breastmilk UP TO 6hrs
infants <6/12, formula up to 4hrs & breastmilk up to 3hrs

Measures:
aiming to reduce the acidity & volume of gastric contents
pharmacologic:
PPI; longer onset but long DOA, reduce volume & pH but don’t change pH of secretions already in stomach
H2 antagonist: sim to PPI, many off marked due to NDMA
sodium citrate/antacid: non-particulate preferred. reduce pH of existing gastric content but mildly elevate volume
prokinetics (eg. metoclopramide)

RSI w cuffed ETT (could use cricoid 10n incr to 30N after LOC; most evidence suggests it isn’t harmful & may be benefical; if making ventilation or laryngoscopy difficult release it. DON’T use cricoid for RSI w acute C spine ord injury or suspicion)
consider NGT or OGT & aspirate stomach
extubate ramped, fully reversed
anti-emetics

No measures have been shown to reduce incidence or severity of gastric content aspiration but low incidence (1:900-10,000 adults, 2:10,000 chn), more freq in emergency
interestingly, multicentre series of almost 140K paeds pts suggested incidence of aspiration similar whether fasted or not (fasting status not an independent risk factor for aspiration!
1.5mL/kg residual volume typically left in stomach (?<50mL) despite fasting, due to secretions from gastric glands, swallowed saliva)

RSI indicated for:
full stomach (emerg surgery, trauma, not fasted, pregnancy after 20/40)
GI pathology (gastroparesis, SBO, GOO, oes stricture (consider NGT to decompress stomach before induction. this doesn’t guarantee empty stomach; while presents of NGT may impair LOS & UOS, cadaver studies show cricoid effectively prevents regurg w NGT in place), GORD
-incr IAP (morbid obesity, ascites)

Question 303

IT_AM 1.5: Describe the indications for manual in-line stabilisation of the neck and the implications for airway management

Answer 303

employ if clinical suspicion of c-spine injury incl:
-high risk mechanism (blunt trauma (eg. fall >6m adult >3m child or >2-3x height, MVA w death of other passenger, speed >64kph, extrusion from vehicle, long extrication), axial load); not indicated for isolated penetrating trauma, no secondary blunt injury& intact neuro exam.
-altered GCS (incl intoxication or drowsiness)
-neck pain
-posterior midline C-spine tenderness
-reduced neck ROM
-neuro deficits
-multi-system trauma
-if a child w underlying predisposing factors eg. w DS or EDS

protection must continue until cleared clinically and/or radiologically

Continue MILS for airway management incl BMV & intubation; if hard collar on, open & apply MILS for this- should NOT try intubation w anterior portion of C spine collar in place as intubation w collar in place ass’d w greater spinal subluxation than w anterior portion of collar removed & MILS in place.

MILS may make airway more difficult (can’t do chin lift or jaw thrust easily);, additional team member in space, expect at least 1 grade C/L worse view VL, D-blade, McCoy, stylet, fibreoptic
use VL w hyperangulated blade & bougie for the 1st intubation attempt

collars CI if neck swelling, fixed neck deformity, need for cricohthyroiditomy or if colllar placement worsens any neuro deficit

Question 304

IT_AM 1.6
Outline the equipment required to be immediately available for basic airway management and the ‘can’t intubate, can’t oxygenate’ (CICO) situation

Answer 304

self-inflating resus bag w PEEP valve & bacterial/viral filters (eg. ambu)
range of facemasks (varying size size), syringe
oropharyngeal (size red is 5, yellow 4, green 3, 00 pink)& nasopharyngeal airways
range of SGAs (type & size)
laryngoscopes- range sizes (mac 3 & 4), blades incl videolaryngoscope
bougie
tubes range sizes

difficult airway trolley:
designed in a way that’s immediately recognisable w signage to easily locate & accessible, lightweight/easily manoeuvreable (eg. take to any point of care within 1 min)
cognitive aids accompanying & checklist of content audit, template of difficult airway letter, emergency contact numbers
bulkier ancillary items eg. flexi bronchs w monitors or HFNO may be on a separate mobile stand. for flexi bronchs, should also have: spare battery or light source, intubating catheter, mouth guard, bronchoscopy swivel connectors, anti-fog, LA with administration devices, nasal VC, bite block/oral intubating airway

ideally universal across the hospital, large procedural area
Ideally paeds equip in dedicated paeds DAT, sizes appropriate to facility

ESSENTIAL:

-clear/opaque rubber facemasks for small, med, large adult
-neonatal size 0 FM for adults w trache stomas
-oropharyngeal airways size 70mm (white, size 2)-11mm (orange, size 6)
colours white green yellow red orange
-nasopharyngeal 6-8mm
-lubricant
-gauze

-laryngoscope duplicate MAC 3&4 w handles, long & short
-spare batteries for handles
-VIDEOLARYNGOSCOPES w blades: incr first pass success, reduce number of failed intubations esp in pts presenting w known or predicted difficult airways. improve glottic view, reduce airway trauma. No evidence that V-L reduces time to intubation, incidence of hypox or resp complications.

-ETTs cuffed size 5-8 adults, microlary 5-6mm.
-blunt malleable atraumatic stylet
-lubricating gel
-surgical tape
-tracheal tube cloth tie
-scissors
-Magill’s
-10 & 20mL syringe

-SGAs: 2nd gen (size 3-5) w easy passage for flexi scope & allow endotracheal intubation. STILL need classic first-gen size 3-5 as low profile & sometimes easier to insert.
orogastric tube sizes 12 & 14Fr
lube gel, 20mL syringe

-fibreoptic
-bougie w 35degree coude tip or steerable tip
hyperangulated blades should be avail but only McCoy or straight if trained in their use.

outside containers vertical:
11&14Fr AECS unfolded
intubating catheters (eg. Cooks), ideally stored in straight position. generally used w flexi bronchs to aid intubation through SGA or occasionally for tube exchange
tracheal tube introducers/bougies

CICO: equip for both scalpel/bougie & cannula.
10mm blade scalpel
frova bougie (TT introducer w 35 deg coude tip)
size 6 ETT
self-inflating BMV
O2 insufflation device eg. easy-O2 or LeRoy
14g cannula w memory fn no safety valve
5mL syringe slip-tip, saline

non-essential: other blades of laryngoscope, guided or channeled, size 4 microlary tube optical stylets

-for paeds
laryngoscopes (direct & video)
mac 1-3 & miller 0-2 blades
compatible blades
spare batteries
TTs uncuffed 2-5.5mm ID
cuffed 3-5.5mmID
microcuff tube ID 3-5mm
stylet 2mm to fit TT sizes 2.5-4.5, 4mm fit 5-8
suction catheters:
2.5mm ET=5Fr
3mm=7Fr
3.5& 4mm= 8Fr
4.5-5mm = 10Fr
6mm = 10-12Fr
7mm= 12Fr
paed DATs have paeds exchange catheters.

Paeds yanker & tubing for suction

Mapleson F (benefits= can see resp movements, can apply IPPV by occluding tail of bag btwn finger & thumb, need FGF min flow 4L/min (2.5-3x MV). compact, no valves, minimal dead space or resistance. use for <20kg chn.

Immediate CO2 detector.

infant, child self-inflating bag w PEEP valve & bact/viral filter

checklist, logbook

lube gel
surg tape
tracheal tube cloth tie
scissors
magill’s forceps paeds
10mL syringe

SADs size 1-4
20mL syringe

paeds facemasks 0-4
oropharyngeal 000-5
NPA 3-5 (described by int diameter)
swivel connector for SGA to place a flexi bronch useful esp infants.

eFONA for kids:
microcuff tube ID 3-5mm
scalpel 10, nurse scissors, towel forceps x3
TT introducer w 35deg coude tip
16g straight cannula w memory function no safety valve
10mL 0.9% saline, 5mL syringe slip tip
O2 insufflation device

Vertical containers w AECs & minimal ID of corresponding TT:
7Fr for >=2.5mm
8Fr for >=3mm
11Fr for >=4mm
14Fr for >=5.5mm
19Fr for >=7mm
the other vertical container should have TT introducers/bougies size 5 & 10Fr (Fr is 1/3 mm)

Grab bags have essential difficult airway equip for rapid deployment to remote areas. should have contents reflecting the facility.
include laryngoscopy, SGA, FMV, eFONA equip, container for anaes/resus drugs (inffridge as needed) w range syringes self-inflating resus bag w PEEP valve & bacterial/viral filter
EtCO2 in-line analysis/colorimetric (purple to yellow w CO2)
checklist, logbook

Question 304

IT_AM 1.6
Outline the equipment required to be immediately available for basic airway management and the ‘can’t intubate, can’t oxygenate’ (CICO) situation

Answer 304

range of facemasks (size), syringe
range of SGAs (type & size)
laryngoscopes- range sizes, blades incl videolaryngoscope
bougie
tubes sizes

difficult airway trolley:
fibreoptic

Question 305

IT_AM 1.8
Describe the common complications of intubation

Answer 305

Time of intubation:
-desaturation (shunt, hypoxaemia)
-aspiration
-dental/oral structure damage (lip/mucosa/tongue)
-SNS response- raised ICP, myocardial ischaemia
-laryngospasm/bronchospasm
-laryngeal (eg. arytenoid) damage
-vocal cord injury
-tracheal injury (esp w introducer/bougie)
-endobronchial intubation & barotrauma from high aw pressures
-oes intubation
-c-spine/spinal cord inury if MILS not maintained when needed

While ETT in:
-tracheal necrosis/stenosis/broncho-oesophageal fistula
-tension PTx
-barotrauma/volutrauma
ETT obstruction/disconnection/dislopdgement
-airway fire
VAP

during extuation:
-laryngeal oedema
dental trauma
-ve pressure pulm oedema

After intubation
-sore throat
-laryngeal injury (oedema/ulceration/VC paralysis)
dysphagia
tracheomalacia, tracheal stenosis, trcheo-oes fistula

Question 306

IT_AM 1.10
Outline an appropriate ventilation strategy suitable for routine elective and emergency patients

Answer 306

lung-protective:
6-8mL/kg tvs, Pinsp <30, PEEP up to 5cmH2O, titrate RR to an EtCO2 35 (confirm on ABG 35-45mmHg)
some pts permissive hypercapnia is tolerated (obstructive lung disease, severe ARDS)
target SpO2 88-95, PO2 >55mmHg

ARDS:
mechanical vent= cornerstone of Rx. proceed directly to invasive mech fent.
initial low TV (4-8mL/kg PBW), vol-limited assist control mode, targeted Pplat <=30cmH2), PEEP titrated to the FiO2/PEEP combos to achieve O2 goal PaO2 55-80mmHg or SpO2 88-95%
LTVV improves mortality in ARDS (several meta-analyses & RCTs)
follow up using clinical, gas exchange or vent parameters

Question 307

IT_AM 1.10
Outline an appropriate ventilation strategy suitable for routine elective and emergency patients

Answer 307

lung-protective:
6-8mL/kg tvs, Pinsp <30, PEEP up to 5cmH2O, titrate RR to an EtCO2 35 (confirm on ABG 35-45mmHg)
some pts permissive hypercapnia is tolerated (obstructive lung disease, severe ARDS)
target SpO2 88-95, PO2 >55mmHg

ARDS:
mechanical vent= cornerstone of Rx. proceed directly to invasive mech fent.
initial low TV (4-8mL/kg PBW), vol-limited assist control mode, targeted Pplat <=30cmH2), PEEP titrated to the FiO2/PEEP combos to achieve O2 goal PaO2 55-80mmHg or SpO2 88-95%
LTVV improves mortality in ARDS (several meta-analyses & RCTs)
follow up using clinical, gas exchange or vent parameters

Question 308

IT_AM 1.11
Outline potential management plans to ensure oxygenation of the patient with an unexpected difficult airway

Answer 308

cognitive aides assist w cognitive load/bandwidth, avoiding task fixation, encouraging team work & helping ensure critical options aren’t overlooked
Primary goal= achievement of oxygenation using either ventilation, insufflation or apnoeic mass movement
Vortex simple approach to maintain O2 used @ my institution.
Lifelines= facemask, LMA & ETT
max 3 attempts at each (game changer= arrival of more experienced clinician possible to add another attempt), each attempt need optimisations eg: manipulations (pt or bed position, dentures, laryngeal manipulation, cuff adjustment)
adjuncts eg. OPA, NPA, introducer, bougie, scope if using LMA, stylet, magill forceps
size/type (different VL blade/handle)
suction
m tone: if prospect of recovery, reverse BZD/opioids/NMBD or if not planning to wake, ensure adequate depth & NMBD
if fail at 3 attempts @ each lifeline (or if SpO2 <90% rprior, committed to surg airw
“green zone” = successful O2 delivery, provides time to pause & plan whether to wake pt or definitive airway Mx

Question 309

IT_AM 1.11
Outline potential management plans to ensure oxygenation of the patient with an unexpected difficult airway

Answer 309

cognitive aides assist w cognitive load/bandwidth, avoiding task fixation, encouraging team work & helping ensure critical options aren’t overlooked
Primary goal= achievement of oxygenation using either ventilation, insufflation or apnoeic mass movement
Vortex simple approach to maintain O2 used @ my institution.
Lifelines= facemask, LMA & ETT
max 3 attempts at each (game changer= arrival of more experienced clinician possible to add another attempt), each attempt need optimisations eg: manipulations (pt or bed position, dentures, laryngeal manipulation, cuff adjustment)
adjuncts eg. OPA, NPA, introducer, bougie, scope if using LMA, stylet, magill forceps
size/type (different VL blade/handle)
suction
m tone: if prospect of recovery, reverse BZD/opioids/NMBD or if not planning to wake, ensure adequate depth & NMBD
if fail at 3 attempts @ each lifeline (or if SpO2 <90% rprior, committed to surg airw
“green zone” = successful O2 delivery, provides time to pause & plan whether to wake pt or definitive airway Mx

Question 310

IT_AM 1.11
Outline potential management plans to ensure oxygenation of the patient with an unexpected difficult airway

Answer 310

cognitive aides assist w cognitive load/bandwidth, avoiding task fixation, encouraging team work & helping ensure critical options aren’t overlooked
Primary goal= achievement of oxygenation using either ventilation, insufflation or apnoeic mass movement
Always check circuit integrity, FiO2 00%, call for help/communicate/delegate (useful to have a timekeeper, someone who monitors SpO2 & etCO2, assisting w situational awareness)
ensure pt deep enough
Vortex simple approach to maintain O2 used @ my institution.
Lifelines= facemask, LMA & ETT
max 3 attempts at each (game changer= arrival of more experienced clinician possible to add another attempt), each attempt need optimisations eg: manipulations (pt or bed position, dentures, remove facial lubricant, 2 person FMV technique, laryngeal manipulation, cuff adjustment)
adjuncts eg. OPA, NPA, introducer, bougie, scope if using LMA, stylet, magill forceps
size/type (different VL blade/handle)
suction
m tone: if prospect of recovery, reverse BZD/opioids/NMBD or if not planning to wake, ensure adequate depth & NMBD
waking the pt may be an option if factored into anaes plan eg. inhalational or TIVA spont vent
consider diff airway trolley if green zone prior to subsequent intubation attempts
CICO READY early (after 3 attempts at 1 lifeline unsuccessful)
if attempting intubation & unsuccessful, CICO SET (after 3 attempts @ 2 lifelines unsuccessful)
if fail at 3 attempts @ each lifeline (or if SpO2 critically low at any earlier point, whereby may decide on less attempts at lifelines prior to FONA)
“green zone” = successful O2 delivery, provides time to pause & plan whether to wake pt or definitive airway Mx

Question 311

IT_AM 1.12
Outline the clinical features, possible causes, physiological consequences and management of perioperative upper airway obstruction

Answer 311

pre-op Ax: Hx snoring, radiotherapy, dysphagia, inability to lie flat, Hx accidental ingestion, Hx recent dental work, viral infection (croup), unvaccinatied & recent URTI epiglottitis, bac tracheitis, oversedation
exam: reduced GCS (eg. if oversedation), stridor (intrathoracic=exp extrathoracic= insp, glottic eg. laryngospasm may be insp & exp or quiet), thick neck, desaturation, incr WoB, sitting in sniffing position or tripoding. may have fever, neck collection. exp wheeze suggests bronchospasm.
Ix: FNE, CT/MRI

physiological consequence: hypoventilaion–> hypox hypercarbia, resp acidosis, risk arrest
-ve pressure pulm oedema if inspn vs obstructed UA
chronic (eg. OSA): hypercarbia, pulm HTN, cor pulmonare, polychtyhaemia, incr risk CVA, CAD

Rx guided by cause, location of securing airway dependent on urgency & recent clinical course
if suspect preop, anticipate for safest induction (eg. spont vent or AFOI)
control source/holding measures first (eg. neb Adr, IV dex, HFNO, ABx commenced) & resuscitate (eg. IVT for sepsis) within time constraints prior to induction
ensure adequate personnel assembled (eg. ENT)

consider postop ICU intubated esp if airway oedema

Question 312

IT_AM 1.13
Describe a ‘can’t intubate, can’t oxygenate’ drill, including the technique for performing an emergency surgical airway

Answer 312

SAQ on old laptop 2022A05

Question 313

IT_AM 1.15
Describe the features of oesophageal and endobronchial intubation and outline appropriate management

Answer 313

Proper endotracheal placement in trachea must be confirmed immediately.
oesophageal:
EtCO2 determination is most accurate means of confirming ETT in trachea; oesophagus may yield small detectable CO2 during first few breaths so need 5x exhalations w consistent CO2 before confidently assume the ETT in trachea.
Visualisation of ETT passing the cords, misting of tube w ventilation & ausc of breath sounds over lung fields, chest rise & fall corroborating evidence likely placement but can’t be relied on (hence EtCO2 essential)
Equal breath sounds in axillae & absent over epigastrium suggests proper placement. if using bougie, bumping on rings & halt @ carina useful.
oesophageal detector devices: suction w syringes or bulb suction. not infallible but can be useful eg. in cardiac arrest. work on principle that trachea is rigid & allows free flow of air while oesophagus collapsible, permits little airflow when suction applied, if withdraw >30mL gas from ETT sans resistance it’s likely in trachea.
US may have a role, flexible intubation scope, if immediately available, useful!
If oesophageal, pt will desaturate, hypoxaemia risk arrest if don’t rapidly remove tube, re-oxygenate & re-attempt (while in green zone, consider reasons & troubleshoot to optimise next intubation attempt)

endobronchial:
tacchycardia, high airway pressures, unilateral lung inflation, hypercapnia, risk PTx.
unequal breathsounds in axillae, CXR, flexible scope, comparing depth, lung sliding US.
deflate cuff, withdraw, re-auscultate & re-secure

Question 314

IT_AM 1.17
Describe the clinical features that indicate a patient can be extubated safely

Answer 314

DAS “low risk” extubation= fasted, uncomplicated airway, no general risk factors

DAS general risk factors:
cardiovascular disease
respiratory disease
neurologic conditions
severe GORD
metabolic disorders
special surgical requirements (eg. drainage neck abscess, head & neck surgery, haematoma)
special medical conditions

airway risk factors:
known difficult airway
restricted access to airway
airway deterioration during surgery (trauma/oedema/bleeding)
unfasted/obese/OSA/obstetric/other aspiration risk

DAS guidelines; if “at-risk” of airway obstruction on extubation, consider delayed extubation or planned tracheostomy
options: LMA while pt deep (if wanting to limit pressor response to extubation)
extubate over flexi bronch
could also inspect the cords w flexi bronch down an LMA; if concern re: larynx, AIC over bronch through cords, remove bronch & LMA, pass tube

AEC: if pass cuff leak test ie >110mL diff cuff up vs down, never inserted beyond 25cm in adult, distal tip must remain above carina, secure in midline, label to avoid confusion w OGT extubate, keep AEC in (pt to ICU) for appropriate period of observation

complications @ extubation:
trauma to larynx, adhesion of tube to tracheal wall, failure to deflate cuff (VC damage)
CVS response (HTN, tachy, risk myocardial O2 demand>supply); consider lignocaine, clonidine, hydralazine
raised ICP (cough/strain, CVS response)
-ve pressure pulm oedema if bite tube: usually young fit adults; airway obstruction & resp distress, haemoptysis, bilat radiological features consistent w pulm oedema (usually resolves within 24hrs, Mx w positive airway pressure & oxygenation
tracheomalacia (eg. secondary to prolonged insult by malignant retrosternal mass or prolonged intubation; insp stridor, exp wheeze, failed extubation. if risk but deemed safe to trial extub, use AEC, extubate deep to avoid coughing, miaintain CPAP
coughing/sore throat
hypoxaemia if inadequate MV, UA obstruction, bronchospasm, laryngospasm, diffusion hypoxia, shivering, decr CO or residual NMB (pre-O2 100% before extubate, ensure reverse sed/hypnotics, analgesia, upright, suctioned, normal TVs on spont vent)
laryngeal oedema, VC paralysis/dysfunction (may require re-intubation)
pulm aspiration

Pt:
awake, obeys commands, adequate power
normoxia (SpO2 >90% on low FiO2), normocapnia (PaCO2 <50mmHg), good tidal volumes spont vent
normotension (minimal inotropic support), normothermia (temp >34deg)
BGLs & otherwise normal metabolic state

Surg:
no contraindications eg. airway swelling/bleeding, raised ICP or brainstem surgery, surg not excessively prolonged or significant complication (eg. major blood loss, vocal cord paralysis, long trendelenburg, excessive IV volume)

Optimal extubation:
Plan–> prepare–> perform–> post-extubation care

Anaes:
upright, suctioned carefully under DL (incl post pharynx), bite block in place, throat packs removed, full reversal of NMBDs, pre-oxygenation to EtO2 >90% prior to extubation
sedative/hypnotics reversed
(if coughless, having remifentanil infusion w effect-site target 1-1.5ng/mL assists smooth emergence, obtunds CV responses, reduces agitation & coughing)
consider AEC in carefully-selected pts (ONLY if pass cuff leak test)
only safe to extubate if have backup plan

Pt suitable to go to recovery if:
patent airway
spont resps w good Vt & SpO2
adequate reversal NMB & sedative/hypnotics
no complicaitons on extubation

Question 315

The anion which contributes the most to the anion gap is

Answer 315

Albumin

normal anion gap 8-12

Question 316

Of the following drugs, the least likely to cause pulmonary vasodilation when used at low
doses in patients with chronic pulmonary hypertension is

Answer 316

dopamine

Question 317

sux tbw vs IBW in obese results in

Answer 317

similar onset, longer duration