ENT Flashcards

Question 1

Q

Describe the chambers and layers of the eye

Answer

A

Chambers:

Vitreous chamber
Anterior chamber
1. Cornea to iris
2. Filled with aqueous humor
3. Aqueous humor drains from anterior chamber thru Schlemm’s canal into venous system
Posterior chamber
- Iris to lens and ciliary process

Layers:

Sclera (white part)- outermost layer
- Tough, fibrous
- Cornea- visual fx
  1. Curvature of cornea is where we have visual power
  2. Tissue where cornea meets sclera is limbis
Uveal tract- middle
- Choroid- layer of blood vessels- bleeding of choroid can cause expulsive hemorrhage
- Iris- controls light entry (changes size of pupil)
  - SNS stim → dilate pupil (iris muscle contracts)
  - PSNS stim → myosis (constrict) → pupil constrict (iris sphincter muscle contract)
- Ciliary body- produces aqueous humor
Retina (innermost layer) – nerve tissue cont. w/ optic nerve . no capillaries. Completely dependent on choroid layer to provide o2 and nourishment to retina

Question 2

Q

What are the 6 extraocular muscles of the eye?

Answer

A

6 muscles –

superior rectus
inferior rectus
medial rectus
inferior oblique muscle
1. (1-4 innervated by oculomotor nerve- CN III)
lateral rectus muscle
1. innervated by abducens nerve- CNVI.
superior oblique muscle
1. innervated by trochlear nerve- CN IV.

Sit in cone behind eye

All surround optic nerve, artery, vein, ciliary ganglion

Question 3

Q

Describe the motor innervation of the eye?

Answer

A

Cranial Nerve III- Oculomotor
- innervates the superior rectus, medial rectus, inferior rectus, and inferior oblique eye muscles
  - Eye movements
  - Pupil constriction
  - Opens eyelid
    - PSNS fibers
Cranial Nerve IV- Trochlear
- innervates the superior oblique muscle
  - Moves eye down and outward
Cranial Nerve VI- Abducens
- innervates the lateral rectus muscle
  - Moves eye lateral

Sympathetic fibers from carotid plexus travel through ciliary ganglion → innervate dilator muscles

Ex: block ciliary ganglion → fixed/dilated pupil

PSNS- CN III

Question 4

Q

Describe the sensory innervation for the eye.

Answer

A

TRIGEMINAL nerve (CN V) – touch/pain
- Ophthalmic branch (VI): 1^st branch
  - Innervates the upper eyelid, conjunctiva, and cornea
    - Nosociliary branch (of opthalmic nerve)
      - sensory to medial canthus, lacrimal sac, and ciliary ganglion
        Ciliary ganglion → provides sensory to cornea, iris, and ciliary body
    - Also regulates OCR (oculocardiac reflex)
- Maxillary branch (V2): 2^nd branch of 5
  - Innervates lower lids
Facial nerve: VII- Exits skull in stylomastoid foramen
- Supplies motor innervation to orbicularis muscle via zygomatic branch
  - Ex: block CN VII → cant squeeze lid
    - Innervates the lower lid

Question 5

Q

What is normal intraocular pressure?

Answer

A

Normal: ~ 16 mmHg (+/- 5)
Abnormal: > 25 mmHg
- Must maintain normal IOP to maintain normal curvature of cornea
- IO perfusion pressure related to CPP
  - (MAP – IOP → how eye regulates perfusion)
  - Ex: High IOP → impairs BF to optic nerve (fx effected)

Question 6

Q

How is aqueous humor produced?

Answer

A

Posterior chamber:
- 2/3 produced by ciliary body (~80-90%)
- → then actively moved from posterior chamber to anterior chamber by an active sodium pump mechanism.
  - Active Na pump (AKA → Na-K ATPase carbonic anahydrase enzyme)
Passive filtration: 1/3 (~20%)
- comes from passive filtration through vessels in iris. across ciliary epithelium
Aqueous fluid is produced at a rate of 2 uL/min.

Question 7

Q

How is aqueous humor eliminated?

Answer

A

Fluid drains out of eye through trabecular meshwork (spongy tissue) → - into canal of Schlemm’s and the episcleral venous system (in anterior chamber) → eventually ending up at SVC and RA.
- Drainage system
  - Trabecular meshwork → eventually go back into central circulation
  - Anything affecting flow → cause increase IOP

Question 8

Q

What can happen if elimination of aqueous humor is impaired?

Answer

A

Open angle glaucoma (OAG): Sclerosis of trabecular meshwork
- chronic elevation
Closed angle glaucoma (CAG): Obstruction of Aqueous drainage from closure of anterior chamber angle
- CAG Causes:
  - Iris swelling
  - Anterior displacement
Pts already w/ narrow angle predisposed to acute increase IOP (PAIN & emergency)

Question 9

Q

What determines intraocular pressure?

Answer

A

A measurement of the fluid pressure inside eye
- The globe is a relatively noncompliant compartment and the volume of the internal structures is fixed, except for aqueous fluid and choroidal blood volume.
  - The quantity of these two factors regulates intraocular pressure.
Determined by:
- Production of aqueous humor
- Drainage of aqueous humor
- Changes in choroidal blood volume or pressure
- Extraocular muscle tone
Normal IOP: 10-20 mmHg (~ 16 and +/- 5)
- >25 mmHg, you have problem

Question 10

Q

What can increases and decrease IOP?

Answer

A

Drugs:
- Ketamine (?) → theoretically causes issues but does not directly
- Succinylcholine (increases by 8-10 mmHg)
  - d/t
    - decrease in Aqueous humor outflow
    - increase in choroidal BV
    - increase in CVP
Other:
- MOST SIG INCREASE → Laryngoscopy & Emergence
  - Sympathetic Blunting
  - Less manipulation of AW the better (LMA less increase than DL)
- Position changes
- Coughing, valsalva maneuver, straining, vomiting, HTN, injection of local anesthesia, laryngoscopy, hypercarbia/hypoventilation/ hypoxia, lid pressure, eye compression, forceful lid squeeze (increases to 70 mmHg), pupil mydriasis (dilation)
  - Increases up to 30-40 mmHg

Decrease:

Drugs:
- Most anesthetic drugs:
  - VA (excluding N2O → no effect)
  - Propofol
  - Etomidate
- Opioids
- NDMR
- hypertonic solutions
- Dextran
- Mannitol
Other: Hypotension, hypothermia, hyperventilation, pupil miosis (constriction)

Question 11

Q

What are some anesthetics that have no effect on IOP?

Answer

A

N2O
Versed
~NDNMB

Question 12

Q

What is acetazolamide?

MOA, S/E?

Answer

A

Carbonic anhydrase inhibitor (topical for eye)- brand Diamox

Treatment for glaucoma
Induces:
- decreases IOP*
- diuresis
- reduces aqueous humor production
- K+ depletion (+/-)
  - want preop labs
SE:
- Confusion
- Drowsiness
- Low K
- Low Na
- Acidosis
- Polyuria

Question 13

Q

What is echothiophate?

Answer

A

Tx for glaucoma
Irreversible cholinesterase inhibitor
- Produces:
  - miosis
Systemic absorption may cause total body inhibition of plasma cholinesterase
- CAUTION:
  - Prolong effects of:
    - Succinylcholine
    - Mivacuronium
  - Toxicity w/ Ester LAs
- Very long DOA:
  - Need to stop 4-6 weeks preoperatively

Question 14

Q

Phenylephrine eye drops? s/e?

Answer

A

Produces mydriasis
Associated w/:
- severe HTN
- Arrythmias
- Adverse CV events
  - Very high [] (1 drop = 5 mg)

Question 15

Q

What are clycloplegics?

Answer

A

Atropine and Cyclopentolate

Pupil mydriasis (dilation)
Systemically absorbed
- SE: See anticholinergic symptoms
  - Dry mouth
  - Dry skin
  - Fever
  - Agitation
  - disorientation, psychotic reactions
  - Central anticholinergic symptoms

Question 16

Q

Effect of acetylcholine in eye drops?

Answer

A

Produces miosis
Cholinergic agonist
Causes:
- Bradycardia
- acute bronchospasm
- hypotension

Question 17

Q

What is timolol?

Answer

A

Tx of glaucoma
- B1/2 antagonist
Produces:
- Miosis
- reduction of aqueous humor production
SE:
- Bradycardia
- Bronchospasm
- CHF exacerbation
- heart block
- Issues w/ nursing infants

Question 18

Q

NSAID use in eye drops?

Answer

A

Ketorolac and Diclofenac
- Used for inflammation

Question 19

Q

Scopalamine effect on eyes?

Answer

A

Mydriasis (dilation)
Can causes central anticholinergic syndrome

Scopalamine drug card:

CLASS= tertiary amine anticholinergic that crosses BBB; used for motion sickness, PONV, sedation, bronchodilation; biliary & ureteral SM relaxation; NOT used for reversal of NMB
- (Most potent anti-sialagogue (+++) & sedative anti-cholinergic) (+++)
MOA:
- Competitively inhibit ACh at the muscarinic receptors & decrease PNS activity (preventing decrease cAMP & cGMP);
- causes sedation by blocking Ach effects @ M1;
- increase HR by blocking the ACh effects @ M2;
- relaxes bronchial smooth muscle & decrease secretions by blocking Ach effects @ M2 & M3; also decrease GI secretions;
Pharmacokinetics= lipid soluble; onset- 10 min; DOA- 2 hrs; E1/2- 4 hrs- may last 3-7 days; metabolized by the liver with <1% excreted unchanged in urine
SE= sedation, post-op delerium; increase HR (+), CO, IOP; OH; arrhythmias; blurry vision; decrease secretions (+++) & GI motility; urinary retention; central anti-cholinergic syndrome, bronchodilation (+)
CI= glaucoma, GI/GU obstruction; caution elderly
Dose= 0.3-0.6 mg IV q 4-6 hrs, patch over 72 hours

Question 20

Q

What is the oculocardiac reflex?

Answer

A

Aka Trigeminal-vagal reflex

Reflex triggered:
- → pressure on globe, pain, and / or traction on extraocular muscles, retrobulbar block, orbital injections, trauma, and hypoventilation (hypercarbia and hypoxemia)
  - Ex: *traction on medial rectus muscle
  - Pressure on periosteum
  - Afferent limb arises from ophthalmic division of trigeminal nerve → goes to gasserian ganglion and sensory nucleus of trigeminal nerve near the 4^th ventricle
    - Afferent limb synapses with motor nucleus of vagus nerve → efferent impulse that travels to heart (via vagus nerve) → leads to:
      - Decreases HR
      - Decrease contractility

Question 21

Q

What is the oculocardiac reflex associated with?

Answer

A

Bradycardia
atrioventricular block
ventricular ectopy
negative inotropy
asystole
- Occurs most often during strabismus surgery (peds pts)
  - Pulling/traction of medial rectus muscle
- May be seen more often under topical anesthesia

Question 22

Q

How can you reduce the occurrence of the OCR?

Answer

A

Maintain normal ETCO2, SpO2
Pretreat with anticholinergic
- (atropine or glycopyrrolate)→ have ready
- Considerations:
  - *Pts typically elderly (increasing HR decreases coronary perfusion pressures)

Question 23

Q

Treatment of OCR?

Answer

A

Stop stimulus
Assess ventilation:
- Correct hypoxia/hypercapnia (can worsen reflex)
  - Admin: 100% FiO2
- normal ETCO2? SpO2?
Deepen patient
Atropine 7 ug/kg increments or Glycopyrolate
- Worsen → Epi
Local anesthetic (lidocaine) into muscle

Question 24

Q

Preop assessment of ophthalmic patient?

Answer

A

High risk population/low risk surgery
Elderly, co-morbidities
- These Pts cannot typically have outpt sx:
  - Severe cardiomyopathy, pulmHTN
  - Home O2
  - Super morbid obese
  - Known DAW
    - OK to do just 1 mg Midaz
- Chronic conditions that may make it difficult to lie still and /or supine
  - SOB, chronic cough, nasal drip, reflux, nausea
  - Parkinson’s, Alzheimer’s or claustrophobia, mentally disabled, back pain, OSA
Pediatric patient cooperation
Non-english speaking, deaf
- Might have to consider more than MAC case
EKG not indicated per AHA/ACC
NEED to educate pt on what to expect. pt needs to stay still, will have blue drape over face
30% of eye injury during ophthalmic surgery with anesthesia were related to patients moving.
Blindness was the outcome in all cases!
Most problems occurred under GA, 25% under MAC.
**Ensuring pt immobility during the procedure are therefore of the utmost importance

Question 25

Q

Preparation for ophthalmic sx?

Answer

A

Pre-operative ophthalmic drops
Continue home medication regimens
Education of being awake/still during surgery (what to expect)
- Blue drape over face
- Wont be able to see
- Duration
Avoid over-hydration
Control HTN
Control BS
No steroid coverage needed
Dry secretions
- Sniffing/coughing → causes movement
Treat reflux
Good intraoperative positioning
- Preop:
  - Preexisting anticoagulants
    - weigh risks vs benefits (talk to surgeon)
    - don’t have to stop anticoag necessarily
- ASA Recommendations:
  - ASA 1 or 2: No routine preop lab testing before cataracts sx
  - EKG done based on pt hx
  - considered low risk sx

Question 26

Q

Technique for sedation for eye surgery?

Answer

A

Technique:
- All standard monitors on
- Supplemental oxygen by NC
  - Blend w/ air if using cautery
- Positioned for comfort
- Meds: Mild/Mod sedation
  - Propofol bolus @ 0.5 mg/kg for block placement only
  - Midazolam 0.5-1 mg and/or Fentanyl 12.5-50 mcg
    - Ex: cataract sx- just topical LA needed
- Avoid CO2 build-up under drapes
  - also avoid O2 buildup- use suction
Additional info:
- 60-70% ophthalmic sx: combo of block & MAC
  - MAC:
    - Less hypotension
    - Faster recovery
    - Less PONV

Other drug options

Precedex, slower onset, nut used normally
Ketamine causes too much dysphoria, esp in elderly
Just need propofol when giving the actual block

Question 27

Q

Induction considerations for general anesthesia for eye surgery?

Answer

A

Smooth intubation
LMA ok
Avoid: meds increasing IOP
- Ketamine
- succinylcholine
Blunt responses to airway maneuvers/avoid pressure on eye
Avoid N2O
- Ex: bc injection of gases (sulfahexafluride, octofluropropane) to cause retinal tamponade
  - Avoid N2O use for 3-8 wks

Question 28

Q

Maintenance considerations for general anesthesia for eye procedures?

Answer

A

Avoid:
- Hypoventilation/ may want mild hyperventilation
  - Ex: acidosis → increases IOP
- HTN (treat)
- bucking or moving
- direct pressure on eye
Typically not a very stimulating procedure once eye topicalized, may need lower anesthetic during case.

Question 29

Q

Emergence and postoperative considerations for general anesthesia for eye procedures?

Goals for general anesthesia for eye procedures?

Answer

A

Emergence
- Smooth wake up
  - Prevent coughing, bucking, vomiting
    - Ex: Propofol, IV lidocaine, deep extubation
- Pretreat w/ antiemetics
Post-operative
- Treat PONV
  - 2fold- some risky for increase N/V (like strabismus sx) and increase IOP
- Good pain control

Goals: smooth induction, stable IOP, avoid OCR, motionless field, smooth emergence, NO N/V, No postop pain

30% cases req GA
- Peds
- Adults w/ cog impariement
Watch fluids

Question 30

Q

What is open angle glaucoma and closed-angle glaucoma? What are the treatments for each?

Answer

A

Open angle glaucome:

Sclerosis of trabecular tissue → causing increase IOP → affecting vision
- develops slowly and bilaterally
-Treatment:— frequently just treated by meds, more chronic process
- Miosis (eye drops that cause miosis acetylcholine, echothiopate)
- decrease production of aqueous humor
- trabecular stretching

Closed angle glaucoma:

Peripheral iris moves into direct contact with corneal → mechanically obstructing aqueous flow
- acute process, more rare
Treatment:
- Immediate surgery
  - Glaucoma is characterized by an increase in IOP to the point where blood flow is compromised (diminished capillary blood flow to the optic nerve) and the optic disc is compressed, which will eventually lead to blindness
- Avoid elevation in IOP

Question 31

Q

Anesthesia management for glaucoma surgery?

Answer

A

Surgeries performed:
- Laser trabeculoplasty
- Trabeculectomy
- Tube-shunt surgery
Anesthetic Management
- Continue medical management to maintain miosis
- Limit the use of anticholinergics (cause dilation)
- Avoid increases in IOP
- If severe acute glaucoma attack- dry pale painful eye:
  - treat w/ Mannitol or Acetazolamide

Question 32

Q

What is retinal detachment? Surgical treatments?

Answer

A

Defined:
- separation of retina from its attachments to its underlying tissue w/in eye.
- Result of:
  - Retinal break, hole, or tear
Surgical treatments:
- scleral buckle
- vitrectomy
- pneumatic retinopexy (injection of gas)
- cryotherapy
A retinal detachment is a medical emergency

Question 33

Q

What are some anesthetic considerations when intraveitreal injection of gas is performed?

Answer

A

Pneumatic retinopexy:
- repair retina, then use insoluble or poorly diffusible gas to tamponade retinal break against the wall of the globe
Caution when using N2O
Sulfur hexafluoride (SF3)
- No N2O for 10 days post-injection
Perfluoropropane (C3F8)
- No N2O for 30 days post-injection
Air
- No N2O for 5 days post-injection

Question 34

Q

Anesthesia considerations for open globe injury?

Answer

A

Concerned w/ open eye injury VS. full stomach
- Concerns: Balance b/t
  - aspiration risk
  - blindness risk (from increased IOP or extrusion of ocular contents)
Contraindicated:
- Ophthalmic blocks
Technique:
- RSI (d/t risk of full stomach)
- Succs- ok
  - (risk of lost AW>> small increased IOP)
    - DL increases IOP a lot → RSI quickens intubation and theoretically decreases IOP (rsi also decreases risk for hypoxia/hypercarbia which also increases IOP)
  - Roc- 1.2 mg/kg for RSI ok
- Need to limit increased IOP
  - Succs admin w/ propofol helps
- Need motionless surgical field

Question 35

Q

What is strabismus?

Answer

A

Most common pediatric ophthalmic surgery
- Misalignment of visual axis w/:
  - Amblyopia
  - Diplopia
  - loss of stereopsis

Question 36

Q

Considerations during strabismus procedures?

Answer

A

Generally a myopathy of extraocular muscles
- → risk of pt having myopathy!
LMA (peds pop)
Risk increased:
- MH
- PONV
- OCR- oculocardiac reflex
  - from direct muscle manipulation/traction
    - ex: tell surgeon/remove stimulous
    - bradycardia persists → admin glyco or atropine
- Oculorespiratory reflex → respiratory pauses
  - Afferent limb same as OCR
  - Efferent limb don’t know what efferent limb is
    - Not responsive to anticholinergics
    - Not typically problem bc already assisting vent (LMA)

Question 37

Q

What surgeries are at increased risk for POVL?

Causes of POVL?

What to avoid?

Answer

A

Surgeries:

Cardiac
Neuro/spine
Head and neck

Causes: KNOW

Ischemic optic neuropathy
- can be Anterior or Posterior ION–> occurs at optic nerve
  - unknown exact etiology, may be due to increased venous pressure and interstitial tissue edema compromises blood flow to optic nerve
- Most common insult: risk higher w/ →
  - Large BL
  - > 6 hr sx
  - Prone sx- venous congestion
Central retinal artery occlusion
- Occurs at optic disc → permanent blindness
- d/t increased IOP d/t external pressure during positioning
  - interruption of arterial supply to retina from increased IOP due to external pressure during positoning
- painless vision loss/decreased acuity
  - prognosis for recovery of vision is pretty poor
Cortical vision loss- results from embolic or ischemic damage to visual cortex

Avoid:

getting chlorhexidine in eyes (chem burn)
avoid warm items

Other eye complications:

corneal abrasion- lubricant, tape, rubbing eyes
chemical injury
thermal injruy
hemorrhagic retinopathy
retinal ischemia
acute glaucoma attack

Question 38

Q

Considerations for preop evaluation for airway surgery?

Answer

A

Good AW assessment- high risk CICV situation
- Size/Mobility/location of lesion(s)
- OSA ?
  - Eval CT scan, conversate w/ ENT surgeon
  - ENT surgeon usually has already done preop endoscopic exam in office and will know what airway will looks like
Evaluate:
- Stridor
  - implies airway diameter < 4-5mm
- Hoarseness
- Voice change
- Difficulty laying flat

Question 39

Q

Operative planning for airway surgery?

Answer

A

Table position in OR
- Need extra length to circuits and IV tubing
Muscle relaxation or no?
- Monitor Nerve fx → be aware of type of case
Pre-Medications:
- Anticholinergics:
  - Reduces vagal tone
  - reduces secretions
  - increases bronchodilation
- Corticosteroids: ~8-12 mg
  - Decrease edema formation
  - reduce N&V
  - prolong LA analgesic effects
*PONV:
- Blood/sx in stomach
  - Decompress belly
- Throat pack- minimizes runoff
  - Make sure to take out
- Antiemetics
Deliberate controlled hypotension
- MAP 60-70 mmHg
  - A-line
  - Drugs: ex BB

Question 40

Q

Postoperative considerations for airway surgery?

Answer

A

Head up position
- Decreases edema
Observe for bleeding, edema
Administer humidified oxygen → decreases swelling
Watch for pneumothorax
Watch for respiratory failure
- Stridor: Tx of laryngeal edema
  - Steroid- prolonged onset
  - Racemic epi mist*

Question 41

Q

Anesthetic techniques for airway surgery?

Answer

A

Closed system- w/ cuffed ETT
Open system- sharing AW w/ surgeon
- Spontaneous ventilation and insufflation techniques
- Muscle paralysis and jet ventilation

Question 42

Q

Discuss the advantages and disadvantages of a closed system with cuffed ETT during airway surgery

Answer

A

Advantage:
- Routine technique
- Protection of lower airway
- Control of airway
- Control of ventilation
- Minimal pollution by VA
Disadvantages:
- Surgical access and visibility limited
- Small ETT → High ventilation pressures needed
- VC damage w/ intubation
  - Esp if lesions on VC
- Risk of laser airway fire

Question 43

Q

What are some ETTs used during airway surgery?

Answer

A

Small ETT

Microlaryngoscopy tubes (MLT)
- 4-5mm
- Long, small tubes w/
- high-volume/low-pressure cuffs
Laser tubes
- Metal tube (only fire-resistant tube)
  - NO cuff
  - Or double-cuffed
    - Colored saline in cuff (if perforated by laser → see blue in field)
Closed system is Beneficial:
- Prevent extubation, disconnects, and leaks
- Assess ventilation continually
  - Observe chest movement, auscultation, pulse oximetry, ETCO2, blood gas analysis
- Orchestrate turning

Question 44

Q

Pros and cons for open systems during airway surgery?

Answer

A

Advantages:
- Laser safety
  - Wont be ventilating when laser used
- Reduced risk of ETT-related trauma
- Complete laryngeal visualization* by surgeon
Disadvantages:
- Unprotected lower airway
- Lack of control of ventilation
- Operating room pollution w/ VA
- Specialized knowledge, equipment, experience required
  - Know how to use JET

Question 45

Q

Describe the airway management of an open system maintaining spontaneous ventilation?

Answer

A

SV and Insufflation technique
- Spontaneously breathing patient with natural airway
- Insufflation of anesthetic gases via
  - A small catheter in nasopharynx and above laryngeal opening → giving O2 and VA
  - Tracheal tube cut short and placed in nasopharynx emerging just beyond soft palate
  - Nasopharyngeal airway
  - Side-arm channel of laryngoscope or bronchoscope

Question 46

Q

Describe the jet ventilation technique during airway surgery?

Answer

A

Subglottic jet ventilation by:
- Jetting needle attached to a laryngoscope or bronchoscope
- Transtracheal catheter thru cricothyroid membrane
  - ETT: Small-diameter (2-3 mm), cuffed/uncuffed, specifically designed for jet ventilation
Provides high-frequency (>1 Hz, 60 breaths/min) w/ ventilator rates 100-150/min
- Automated high-frequency ventilators with alarms and automatic interruption if pressure limits reached

Hand-triggered devices- usually low-frequency jet ventilation (8-10 breaths per min) to allow adequate time for exhalation via passive recoil of lung and chest wall and prevents air-trapping and build-up of pressure in small airways; Ventilate at low pressures of 30-50psi. [least amount possible] Inspiration is 1.5secs, expiration 6secs

High-frequency jet ventilators (oscillatory ventilation) jets gas at 1-10 Hz; both inspiration and expiration are active; driving pressure, frequency, inspiratory time, and composition of jet gas can be adjusted

Question 47

Q

Considerations for anesthesia with jet ventilation?

Answer

A

Preoxygenation
IV induction
NDMR* (paralyzed/apneic patient)
Laryngoscopy
Topical LA
LMA or ETT inserted
Ventilation w/ 100% oxygen until surgeon ready to site the rigid laryngoscope with jetting needle
Anesthesia maintained with propofol infusion + remifentanil infusion
- TIVA typically better
At the end of surgery, LMA reinserted
NDMR antagonized (reversed)
Anesthetic infusions stopped
Smooth awakening and LMA/ ETT removal

Question 48

Q

How can you assess the adequacy of jet ventilation?

Complications of jet ventilation?

Contraindications to jet ventilation?

Answer

A

Adequacy of jet ventilation assessed continuously by:

Observation of chest movements
Oxygen saturation readings
Listening for changes to the sound during air entrainment and exhalation
Observation of airway patency

Complications of jet ventilation:

Crepitus
Pneumothorax
Barotrauma
Gastric distension

Contraindicated in

children [have a higher incidence of pneumothorax/SQ air],
obese pts, and
pts with bullous emphysema

Question 49

Q

Why are lasers used in airway surgery? What are some advantages and hazards to the use of lasers in airway surgery?

Answer

A

Laser light beams are primarily used for thermal effects
- CUT
- COAGULATE
- VAPORIZE tissues
Lasers have one wavelength:
- moving in the same direction
- beam is parallel
- emit small amount of radiation
Advantages:
- very precise
- minimal edema
- minimal bleeding
Most common: CO2 laser common in Airway
- d/t shallow depth of burn and extreme precision
- Long wavelength absorbed by surface tissues

Hazards

Atmospheric contamination
- Plume of smoke and fine particulates- wear special mask
- Deposition in lungs
- Leads to:
  - Pneumonia
  - Inflammation
  - viral infections
    - wear special mask
Vessel/structure Perforation
Embolism
Inappropriate energy transfer
- Reflection/Scatter of beams → cause immediate/delayed injury to normal tissue (esp eyes)
  - CO2-reacts at surface → corneal damage
  - Nd: YAG/argon-pass thru the cornea to the retina
- *TAPE PT EYES CLOSED AND COVER W/ WET GAUZE
- *PROTECT YOUR OWN EYES

Question 50

Q

Fires in laser airway surgery?

Strategies to reduce risk for AW fires?

Answer

A

Fire- lasers produce intense heat

CO2 laser penetrate ETT → ignite fire
- O2 & N2O support fires
Usually the subglottic, epiglottic and oropharyngeal areas are involved
Inhalation of smoke can cause:
- bronchospasm
- chemical injury
- → resp. failure
Strategies to reduce AW fire:
- Reduce flammability of ETT
  1. Double cuff
  2. Metal tube
- Remove flammable materials from AW by using jet ventilation or intermittent extubation with or without apnea
- Reduce available oxygen
  1. < 0.30 FiO2
- Avoid:
  1. paper drapes
  2. oil-based lubricants
  3. caution with alcohol-prep solutions
  4. O2 accumulation under drapes

Question 51

Q

Anesthetic considerations in laser surgery in airway?

Answer

A

Surgical visibility vs airway control
- GETA with laser ETT and methylene blue or NS in the cuff<– most control over airway
- Insufflation techniques thru nasal tube
  - “open” technique – NPA
- Jet ventilation thru jetting arm of scope
- Apneic technique- intubate/extubate pt
*Lowest possible FiO2
*Protect eyes with laser safety eyewear or saline-moistened pads and laser eye shields
*Face and neck should have wet gauze over them
*Have NS readily available to douse fire

Question 52

Q

What actions should you take in the event of an airway fire?

Answer

A

Remove burning ETT and/or other material from airway
Stop ventilation/turn of flows
D/C O2
Flush pharynx w/ cold SALINE
Mask with 100% O2
- When fire is out
Laryngoscopy and bronchoscopy to assess damage
Administer:
- humidified gas
- steroids
- antibiotics
May need to reintubate, or even trach, and control ventilation
Check ABGs, SpO2, CXray, etc

Question 53

Q

When are T&As performed?

What are T&A’s associated with?

Answer

A

Adenoids:
- Massive lymphoid tissue posterior to nasal cavity
  - Become hyperplastic → see obstruction/congestion
  - Take tonsils & adenoids
Indications:
- severe infection of tonsils
- hypertrophy of tonsillar bed
Associated with:
- OSA – LT complications →
  - *Cor pulmonale, PHTN, RV hypertrophy
- URIs
  - Increase virulence post op
  - Increase risk laryngospasm/bronchospasm

Question 54

Q

Preop assessment of tonsillectomy?

Answer

A

Evaluate loose teeth (age 4-7)
? Recent URI
? Recent antibiotic use
OSA
Assess AW – DAW? → Awake FOB**
- Peritonsillar abscess
- Dental Abscess
  - → Lead to Trismus (lockjaw) → impairs mouth opening*

Question 55

Q

Induciton and maintenance considerations with T&A?

Answer

A

Induction
- Possible stridor or obstruction – hyperplastic tonsils
- GA- ETT or LMA?
  - Oral RAE or reinforced ETT (surgeon uses a mouth gag)
  - Tape midline → less likely to kink w/ retractors
Maintenance
- Supine with table turned 45 degrees
- Deep anesthetic level- don’t want coughing
- Hydrate well → poor PO intake postop
- Short-acting narcotics
  - Esp if suspecting OSA

Question 56

Q

Emergence for tonsillectomy

Answer

A

AIRWAY, AIRWAY

SMOOTH EXTUBATION
- High incidence:
  - Laryngospasm
  - stridor
- Admin: Lidocaine/precedex
Throat pack out
Sx/decompress belly
Position on extubation:
- Side-lying with head slightly down
PONV prophylaxis
Pain control:
- Tylenol
- Steroids (for edema/pain)

Question 57

Q

Anesthetic management of the bleeding tonsils?

Answer

A

Occurrence:
- Acutely: < 6 hrs postop
- 7-10 days postop
Determine the extent of blood loss
- Check:
  - Hbg/Hct
  - Coags
  - T&C
Hydrate well
No premedication
CAUTION:
- hypovolemia
- Full stomach (RSI→ swallowing blood)
- airway obstruction
- Potential DAW
  - RSI w/ head down (prevent aspiration of blood)
  - Place NG Tube
  - extubate AWAKE

Question 58

Q

What is epiglottitis? Presentation? Population?

Answer

A

Acute infection of supraglottic structures (epiglottis, arytenoids, epiglottic folds)
Presentation:
- rapid,
- sudden sore throat
- fever
- dysphagia
- drooling
- open mouth
- stridor
- respiratory distress
- tripod position
Population: (differentiate from Croup)
- 2-6 yo
- H-Flu
- Can see in adults, but larger diameter of AW (medically managed)
  - Awake FOB intubation if necessary.

Question 59

Q

Airway considerations with epiglottitis

Answer

A

Do not attempt to instrument AW outside OR and without surgeon ready to perform emergency tracheostomy
- Do not attempt IV, or make cry prior to ready to instrument aiwray
Expect difficult intubation- DAW
Technique:
- Mask induction- Sevo
- Sitting in parent’s lap
- Maintain SV
- Intubate- Smaller ETT
  - then IV’s, atropine
- Difficulty placing tube →
  - Rigid bronchoscopy or tracheostomy
Intubated to ICU 24-72 hours, antibiotics, sedated

Question 60

Q

What is a laryngospasm? How can we reduce occurrence?

Management of laryngospasm?

Answer

A

Exaggerated reflexive glottic closure
- Produced by stimulation of superior laryngeal nerve by →
  - Blood
  - Secretions
  - surgical debris
    - *Esp w/ light plane anesthesia
More common in upper airway procedures
To reduce occurrence:
- IV lidocaine
- topical lidocaine
- deep extubation
Management:
- Increase depth of anesthesia
- Suction (remove blood/secretions)
- 100% FiO2 by tight fitting mask/CPAP - PPV
- Jaw thrust
- Succs: 0.1-0.5 mg/kg

Question 61

Q

What is stridor? Management of stridor

Answer

A

supraglottic issue

Noisy, high-pitched, predominantly inspiratory sound from turbulent airflow from upper AW obstruction
Occurrence: AW diameter
- Adult: < 4-5mm
Management:
- 100% oxygen facemask
- HOB up
- Decrease edema:
  - Nebulized racemic epi 1 mg 1:1000 solution (1mL) in 5 mL NS (q30 min)
  - Dexamethasone: 0.1 mg/kg IV q6hrs
  - Helium (Heliox) → improve laminar flow

Question 62

Q

What is samter’s triad?

Answer

A

Samter’s triad
- Nasal polyps
- Asthma
- Sensitivity to aspirin/NSAIDs → produce bronchospasm

Question 63

Q

Sinus surgery considerations?

Answer

A

Smooth wakeup
Prevent PONV
Throat pack placed → ensure removal before extubation
Topical vasoconstrictor → reduce bleeding
- Can see hemodynamic effects
- Phenylephrine – alpha adrenergic agonist
  - Doses high → see HTN
    - BP monitoring
    - Vasodilators
    - Alpha receptors antagonists
  - Do not use BB → worsen CV output
- *Oxymetazoline (Afrin) – selective alpha 1 agonist/partial alpha 2 agonist
  - More commonly used c/t phenyl- safer
    - Spray in nares preop
  - AVOID:
    - MAOIs → complications reported

Question 64

Q

What are some complications of FESS?

Answer

A

VAE
Trauma to eyes
CSF leak
Excess bleeding
- Want BP lower
Focal neurologic deficit
Death

Answer 65

A

Preop:
- evaluate for OSA → AND s/s of LT complications of OSA
- nasal polyps (develop NSAID sensitivity and asthma with nasal polyps)
  - → Life-threatening bronchospasm (Samter’s triad)
Airway management:
- GETA
- Flexible LMA
MAC

Answer 66

A

LA and vasoconstriction
- Increased doses cause:
  - Tachycardia
  - HTN
  - mycardial irritability
  - myocardial depression
- Onset 1 min, peak effect 5 min, duration 30-60 min
- Usually 4% topical solution
- MAX DOSE: 200 mg

Answer 67

A

alone or w/ lidocaine
- Initial dose of phenylephrine should not exceed 0.5mg
- May cause severe HTN
- Avoid BB and CCB
  - d/t myocardial depression and pulmonary edema
  - ok to give if oxymet given***

Answer 68

A

Epinephrine
- Safe MAX dose: 1.5 mcg/kg (200ug)

Answer 69

A

Maintenance
- HOB slightly elevated
- Deliberate hypotension
- Short-acting drugs
Emergence
- Remove throat pack; careful suctioning
- Gastric suctioning
- Awake extubation to protect airway or “deep” extubation to avoid coughing, bucking
- PONV prophylaxis

Answer 70

A

Nerve preservation (particularly CN VII, IX, X, XI, XII)
- *Nerve monitoring → mastoidectomy
N2O effect on middle ear
- Expansion of space
Control of bleeding
- Cant tolerate bc small space
PONV

Answer 71

A

Patient understanding and cooperation are vital to prevent sudden movement at critical stages of surgery
Local anesthesia w/light sedation good for external ear and cooperative patient
GA for middle ear and inner ear
Airway access during procedure limited
Watch head positioning w/ lateral rotation of head
- Assess preop for NM problems
GETA preferred for length of sx
- Oral RAE
- Reinforced or armored tracheal tube – since head turned
- Flexible LMA
- ProSeal LMA

Answer 72

A

Facial nerve monitoring
- May not want NDMR
N2O-caution with tympanic grafts
Limit bleeding
- Head-up position
- Smooth, balanced anesthetic w/ good analgesia
- Deliberate hypotension (MAP 50-60)
- Keep track of epi doses

Answer 73

A

Very high incidence of N/V
- PONV prophylaxis
- Hydrate
Smooth emergence- no coughing/bucking/retching

Answer 74

A

AVOID: NASAL AW !!!
Difficult FOB intubation → attempt ETT w/ DL
Careful for laryngeal trauma:
- s/s laryngeal pain, dyspnea, dysphagia, dysphonia, SQ emphysema, hoarseness
Avoid cricoid pressure
Assess for other trauma:
Pneumothorax

Answer 75

A

Lefort 1- Transverse fracture thru floor of maxillary sinuses (only palate moves)
Lefort 2- Fracture thru maxillary sinuses (pyramidal fracture)
Lefort 3- Fracture thru orbits (craniofacial dysjunction)
- clinically, may be mixed

Answer 76

A

LeFort I fractures:

May be intubated orally or nasally usually without difficulty

LeFort II and III fractures:

Cranial cavity open and dural tear
S/S:
- CSF in nose
- blood behind tympanic membrane
- periobital edema
- “raccoon-eyes” hematoma- signs of fracture and possible passage into the cranial cavity
CAUTION:
- Cervical spine stability → assess
- subdural hematoma
- pneumothorax
- intraabdominal bleeding
- Other neurological injuries
Considerations:
- Caution NASAL intubation
- May need tracheostomy under LA or awake oral intubation
- Expect blood loss and prepare
- Post-procedure NO access to oropharyx (due to wiring)
  - Wire-cutters available

Answer 77

A

Radical neck dissection: A surgical procedure involving the removal of a tumor from the neck with an additional margin of normal tissue together with the removal of the lymph nodes from the neck. It can involve removal of the mandible and structures in the oropharynx
The resection included the removal of:
- spinal accessory nerve
- internal jugular vein
- sternocleidomastoid muscle
- submandibular gland.
The anatomic structures that remain:
- carotid arteries
- vagus nerve
- hypoglossal nerve
- brachial plexus
- phrenic nerve.
A more conservative operation involves removing all the lymph nodes but sparing the spinal accessory nerve, sternocleidomastoid muscle, and internal jugular vein.
Total Laryngectomy:
- AW ends in blind stoma
- Cut end of trachea comes to neck surface
  - → wakes up with fresh trach

Answer 78

A

Cancer patients: → LABS
- Emaciated
- Dehydrated
- Anemic
Assess co-morbidities
- LT smoker
Assess difficult airway r/t tumor location and size, radiation therapy, past resections
- Eval CT scans
Prepare for position changes with flap reconstruction
Blood available

Answer 79

A

Induction

GETA
- surgical tracheostomy at beginning or during the procedure with J shaped laryngectomy tube → sew in
  - Attn to Peak pressures → freq R mainstem

Maintenance

A-line and CVP?
Good IV access
Deliberate hypotension
- SBP 85-90
- MAP ~ 70
Head up tilt 10-15 degrees
WATCH for:
- air embolism
- carotid sinus manipulation
Ask about surgical nerve stimulator use and NDMR
- Nerve monitoring during dissection phase- can give at induction nd will wear off during line insertion/positioning
- Technique:
  - Remifentanil gtt
  - Sufentanil gtt
  - TIVA w/ small VA (Propofol)
Caution w/ crystalloid use → contribute to AW edema postop

Answer 80

A

New trach irritating and causes coughing
- Humidification, regular suctioning, head-up, local
Pain control
PONV prophylaxis
Watch for trauma to R stellate ganglion and cervical ANS

Answer 81

A

Thyroid gland regulates body metabolism
Indications:
- Cancer, goiter, failed medical mmgt hyperthyroidism
Tx preop for hyperthyroidism → reduce risk of thyroid storm
- CV instability
- A fib
- Ischemia
- CHF
Goiter: → CT scan preop *
- Deviation of larynx
- Tracheal compression
- Horners syndrome
- SVC obstruction

Answer 82

A

Removal of parathyroid glands
Tracheal compression,
Damage to laryngeal nerves (RLN, ext branch SLN)

Answer 83

A

Parathyroidectomy: hypercalcemia/hyperparathyroidism
- d/t benign parathyroidadenoma
- High Ca preop → lower before sx
  - Fluids
  - Lasix
  - Biphosphinates

Answer 84

A

Preop

Want euthyroid (what medications are used?)
Airway assessment

Induction- General anesthesia

Blunt SNS responses/ want to depress SNS responses
EMG ETT (nerve testing)- Nerve integrity monitor (NIMs tube)
- Use video intubation to position tube perfectly at glottic opening
?LMA
- Advantage: spontaneously breathing patient and can access vocal cord function in real-time
- Disadvantage: limited, and possible difficult access to airway

Answer 85

A

Maintenance
- No muscle relaxation/ surgical nerve stimulation
- No esophageal stethoscope or NGT
- Monitor for thyroid storm, compression of trachea
Emergence
- Smooth with no coughing, bucking

Answer 86

A

Hematoma: Airway obstruction
Recurrent laryngeal nerve damage
- Unilateral damage- hoarseness
- Bilateral damage- Vocal cord paralysis and airway obstruction
  - AW emergency
Superior laryngeal nerve damage
- Voice tires easily, high risk of aspiration
Hypocalemia from inadvertant surgical removal of parathyroid glands
- Hypocalcemia
  - Develops within first 1-72 hrs
  - Perioral numbness and tingling, paresthesias, mental status changes leading to :
  - Laryngeal stridor progressing to laryngospasm
    - FOLLOW preop Ca levels to ensure

Answer 87

A

Awake with local
- must be a cooperative pt.
- technically challenging for surgeon; not ideal
General anesthesia (ideal)
- ETT, mask, LMA
- avoid muscle relaxation

Answer 88

A

Watch FIO2 and the use of cautery– airway fire!
IV Lidocaine prior to trach insertion
Pulling ETT technique
- Then cannulate trachea with device
Confirm ETCO2, BBS, O2 sat, airway pressures (Peak inspiratory pressures same when had ETT)

Answer 89

A

Fire triad:

Fuel
Oxygen
Ignition source
- Watch drapes – accumulation of O2
- Dry prep time
- Sponges/guaze moistened

Steps:

Immediately remove ETT
Stop flows
Take flammable material away from AW
Pour NS into AW
Fire out → reestablish AW, admin O2, bronch, reintubate
Not going out → CO2 extinguisher

Answer 90

A

Smooth
Fresh stoma irritating- pain
Humidification, HOB up, oxygen
CXR
Tracheostomy matures in 5-7 days