Airway Flashcards
List indications to secure airway (intubate)
1) the ability of the patient to maintain and protect there own airway –Gag reflex is an unreliable assessment as is missing in 12-25% of patients – Ability to manage and swallow secretion and ability to phonate and follow commands are more reliable intdicators – in general patient who require airway maneuver to establish a patent airway or who easily tolerate oral adjuncts require intubation
2) failure of ventilation or oxygenation -
3) the predicted course and likelihood of deterioration - active resus, pain control, need for invasive procedures and imaging outside of the ED and inevitable OT dictate the need for early airway control- Classic is Tox
4) pain management
5) transport
Discuss physiologically difficult intubation
HHARMMS
Hypotension – Fluid loading, Norad, Reduce induction agent by 20%
Hypoxia- Preoxygenation including thinking about PPV
Acidosis – RR matching
Respiratory conditions – optimise as much as possible
Medications
Medical conditions
Sepsis
Discuss difficult BVM
MOANS
\M: mask seal compromise or difficulty
O: obstruction or obesity – supraglottic obstruction
A: advanced age
N: non teeth, edentulous patients
S: stiffness or resistance to ventilation (asthma, COPD, APO, restrictive lung disease, term pregnancy)
Discus difficult direct laryngoscopy
LEMON
L: look externally - bruised and bloodied face -combative -C-spine immobilisation
E: Evaluate 332 -Glottic visualization necessitates that the mouth opens adequately the sub mandibular space is adequate to accommodate the toungue and the larynx be positioned low enough in the neck to be accessible -332 rule - 3 fingers mouth opening, 3 hyo-mental and 2 between hyoid and thryoid - receding mandible and high riding layrnx make direct visualisation impossible
M: mallinpati
O: obstruction or obesity: -epiglottitis, head and neck cancer, ludwigs angina, neck haematoma, glottis swellgin or glottic polyps can compromise laryngoscopy, passage of the tube or BVM
N: neck mobility
S: poor saturation – not a direct contirbutor to laryngscopy but limits time for intubation –> NIV for pre-oxygenation
Difficult extraglottic device placement
RODS
R: restricted mouth opening
O obstruction or obesity
D: distorted anatomy
S: stiffness – neck/lungs
Difficult cricothyrotomy
SMART – difficult cric can be anticipated whenever there is limited access to the anterior neck or obstructed laryngeal landmarks. -
S:surgery -
M: mass (abcess, haematoma)
A: access/anatomy problems (obesity, oedema)
R: radiation – leading to scarring over the nec,k
T: tumor/trauma
Describe Mallinpati score and anatomy assoicated with each + implications
Class I: Soft palate, uvula, fauces, pillars visible.
Class II: Soft palate, major part of uvula, fauces visible.
Class III: Soft palate, base of uvula visible.
Class IV: Only hard palate visible
Class 1-2 –> easy
class3-4 –> increasingly difficult
Discuss different oxygen delivery devices and the fio2 they can deliver
Non rebreather can hypothetically achieve 100% oxygen however firm seal is almost impossible ot achieve so at best achieves 70-80%
Nasal prong 24-40% depending on flow
Hudson 35-60%
Nonrebreather 80% (100% if full seal)
Discuss RSI
Nearly simulatneous administration of a potent sedative and a neuromuscular blocker for the purpose of intubation.
Provides optimal intubating conditions and has long been thought to minimise the risk or of aspiration.
Central concept is to take the patient from a strating point IE concious and breathing to a state of unconciousness with complete neuromuscular paralysis
What are the 7 Ps of rapid sequence intubation
- Preparation
- Pre-oxygenation
- Pre-treatment
- Positioning
- Paralysis with induction
- Placement of tube
- Post intubation management
Discuss pre-oxygenation – (mechanisms, technique, special pop)
Administration of 100% ogygen for 2 minutes of normal tidal volume breathing establish adequate oxygen reservoir to permit 6-8 minutes of safe apnea before desaturation to 90% - this time is condiderably shorter in children, obese adults, late term pregnant women and patient who are acutely ill or injured
If time is insufficient 8 vital capacity breaths with highflow are equal to the above
Obese patient can have available apnoeic period increased by preoxygenating in upright position and contining apnoeic oxygenation via NP at 5-15L/Min during intubation attempts
Primary mechanisms is denitrogenation of the lung – oxygen washout
Discuss factors that reduce safe apnoea time
critical illness
inadequate preoxygenation
obesity
pregnancy
shunt physiology
airway occlusion
increased oxygen consumption (e.g. high metabolic rate, fasciculations from suxamethonium)
anaemia or dyshaemoglobinaemia
Discuss the purpose of pre-treatment medication in RSI
Pre-treatment medication is used to control the physiological response to laryngoscpy and intubation. ]
Fentanyl 3mcg/kg can be used as a sympothelytic 3 minutes prior to inubatuion to avoid spikes in BP and reduce incrase in sheer forces. Specifically improtant for ICP, Aortic disease, ACS and neurovascular emergency
Bronchodilators to avoid or optimise ventilation
Discuss optimising positioing for airway (Neonate, children, adult, obese, pregant)
Adult: Position the patient with ear-to-sternal notch alignment, n the morbidly build a ramp under the patients and shoulders to achieve this, Avoid excessive atlanto-occipital extension
Infant: Have a comparitivly large occiput- place 1-2 folded towels under trunk to achive neutral airway
Ramp and left lateral for preganat ladies
Discuss confirmation of ETT placement
Co2
POCUS
EXAM
CXR
O2
Fogging of tube
Direct look
Discuss what constitutes a failed airway
Failed intubation without ability to brings spo2 above 90% 3x failed attempts
Discuss apnoeic oxygenation
takes advantage of a physiological principle termed aventilatory mass flow even though muscles have been paralysed circulation and diffusion of oxygen continue creating a gradient promoting passive movement of O2
Discuss delayed sequence intubation
agitation delirium and confusion can make attempts at pre-oxygenation challenging DSI makes use of dissociative doses of katamine (1mg/kg IV)
Discuss HD consequences of intubation
Laryngoscopy and intubation are potent stimuli for the reflex release of catecholamines(RSRL). This normal produces a modest increase in BP and HR and is of little clinical consequence Two setting acute elevation in ICP and certain CVS disease ( ICH, subarachnoid, aortic dissection or aneurysm, ischaemic heart disease) are inportant Fentanyl is good blunting this affect. As such it should not be given to those with HD compromise (bleeding, sepsis
Discuss intubation with acutely elevated ICP
Two considerations 1: maintaining CCP – MAP-ICP 2: minimizing supranormal surges in the MAP which can increase ICP Maintenance of the systemic MAP at 100mmhg or higher support CPP adn reduces liklehood of secondary injury Need to control RSRL
Fentanyl: 3-5mcg/kg IV 2-3 minutes prior to laryngoscopy –> should not be given to patient who are hypotensive or who are dependent upon sympathetic drive to mantain an airway
Ketamine 1mg/kg
Rocuronium 1.2-1.6mg/kg
Discuss intubation of status asthmaticus
Prepare for difficult airway Ventilating with BVM or EGD will be hard due to high airway resistance Low TV, RR and high inspitartory flow with expiratory time set long enough to allow exhalation to avoid autoPEEP. Permission hypercapnia will need to be allowed Asthmatic patient has highly reactive airway and intubaion may cause neurally mediated bronchoconstriction. Local anaethetic usage may blunt this reflex Ketamine has bronchodilatory properties and may mitigate bronchospasms in patients who are not intubated and is a reasonable induction agent.
Discuss intubation in patient with hypotension and shock
In the critically ill patient induction agents have the potential to exaggerate pre-exisiting hypotension. Shock sensitive RSI hinges on 3 primary management principles 1: volume resus prior to intubation if time permits 2: reduced dose induction agent 3: pretreatment with peri-intubation pressors do nor use fentanyl as a pretreatment Use ketamine 50% dose as induction
Discuss Sux works PD and PK and contraindications
PD: binds to ACH receptors causing activation and remaining bound to receptor not allowing further binding of ACH
PK: rapidly hydrolyzed by plasma pseudocholinesterace. 45 seconds to onset and last 8-10 minutes
Dose 1.5mg/kg
Contraindications
CVS effect: -ve chronotrope espeically in children and sinus brady can ensure post use.
Fasiculations
Hyperkalaemia: sux has been associated with severe fatal hyperkalaemai when administered to patients with specific clinical conditions (burns >10% TBSA >5 days, crush injury >5 days, denervation >5 days, NMD indefinitely, intra-abdominal sepsis)
Mechanisms of hyperkalaemia is secondary to upregulation of ach recptors -ACH receptors are essentailly K channels and at risk patients have an immediate massive efflux as newly recuruited receptors are depolarized
Masseter spasm and malignant hyperthermia
Increased intraocular pressure
Discuss factors to optimise intubation attempt
Patient – optimise positioning
Person – Best intubator
Equipment. – Cmac, fibreoptic
-Environment -
Disease process
Discuss approach to airway in neonates and children
Discuss approach to intubation in pregnancy
Discuss Airway sizes in paediatric
ETT size = (age/4)+4
Length at the nose: (age/2)+15
Length at the lips: (age/2) +12
LMA by weight
Discuss doses of circulation and induction drugs for children
Epi: 10mic/kg
Epi infusion: 0.1-0.5 mcg/kg/min
fluids 10-20ml/kg up to 40ml/kg
Defib 4J/KG
Amioderone 5mg/kg
Atropine 20mcg/kg
Propofol 4mg/kg
Sux for laryngospasm 0.5-1mg/kg
Sux for RSI 2mg/kg
Roc 0.6-1 mg/kg
Vec 0.1 mg/kg
Discuss the use of cuffed vs uncuffed tubes
Traditionally uncuffed tube are used for children under the age of 8.
The benefits of a cuffed tube are thought to be: accurate ETCO2 monitoring; protection from aspiration; less tube changes due to air leaks; and continuous lung recruitment
Concern is that cuffed tubes can lead to trauma can lead to erosion, infection, cricoid perichondritis, and ultimately SGS
Uncuffed tubes
Can use cuffed tubes a size lower for paeds under 8
Discuss CICO
Scaple bougei tube in everyone older than 10
needle cricothyrotomy on children under 10 due to very small cricothyroid cartilage and high rates of layrengeal injury and long term complications with scaple
Discuss anatomical difference of a children
- Prominent occiput: neck is flexed in a neutral position – larynsgoscopy is difficult in this position – folded towel under back to acheive neutrality
- Small mandible: less anterior excursion and smaller mouth opening
- Large Tounge: Causes obstruction and interferes with view
- Larger tonsils and adenoids: can cause obstruction risk of trauma and bleeding with NPA
- Superior laryngeal position: Located oposite the c3-4 vertebra compared to c4-5 in adults - more difficult laryngoscopy
- Large floppy epiglottis: projecgts further into the airway and cover more of the glottis - straight blade
- Short trachea - easier to right main and accidentally extubate
- Narrow trachea –> more disposed to obstruction - need to needle cric as small target, concern with SGS with cuffed tubes
- Soft trachea and cricoid - trachea may collapse with cricoid pressure
- Anatomic subglottic narrowing- effective seal without cuff, resolved at 10-12
Discuss post intubation hypotension, clinical finding and interventions for the same
1) Increased intrathoracic pressures
Signs: high airway pressure altered breath sounds
Intervention: Reduce resp rate, less force if BVM, increated expiration time and IV fluid bolus
2) ongoing fluid loss or bleeding
signs: signs of shock, SI >0.8, POCUS with hyperdynamic heart and collapsing IVC
3) induction agent effect
Signs: transient responds to fluids
Intervetion: fluids inotropes as needed, tie
4) PE
Signs: POCUS, distended JVP, possible hypoxemia
Intervetion: fluid bolus , norad infusion
5) tamponade
Signs: POCUS, JVP
Intervention: FLuids, pericardiocentesis
6) Cardiogenic
Signs: ECG, Crackles, CXR, POCUS
Intervention: inopressor, minimise PEEP
7)anaphylctic/sepsis
Discusspost inubation hypoxia causes, signs and intervention
1)ETT malposition (dilodged or oeophageal)
Signs: nil or decreased bilatearl breath sounds, nil CO2, low PIP
INtevention: re-intubate
2) Mainstem intubation
signs: unilatearl breath sounds, CXR
Intervention: pull tube back
3) ETT cuff malfunction
signs: leak or low MV, loss of pilot balloon pressure
Intervention: exchange ETT
4) Mucous pluggin
Signs: increased secretions: high resistance to BMV, high PIP
Intervention: ETT sucntioning
5) Rapid desaturaiton (obesity, late term preganncy, inadequate preoxygneation, intrapulmonary shunt)
signs: sudden drop post induction and NMB
intervetnion: Rescure mask and oral and nasal airways
6) profound shock or anaemai
7) penumothorax
8) oxygen apparatus malfunction
Decribe crash airway
Intubation wihtout medicaiton in a person who has arrested or is agonal
Describe awake oral intubation
A technique in which sedative and local anaethetics are used to facilitate intubation in an spontaneously breathing patient.
Topical anaethesia may be ahcived by spray nebulization or local anaethetic nerve block.
Ketamine is an approaptie dissocaiteive providing, anaethesia, analgesia and maintenance of protective airway reflexes. Dose of 0.5mg/kg are effective. Dexmedatomidine ahve also been used.
After sedation and local gentle direct, video, flexi endoscope or fibreoptic intuabtion is perfromed to determine whether the flottis ivisible and intubation is possible, If visible intuabtion can occur on first look or the operator confident that the glottis cna be visualised may opt for RSI to beneift from pretreatment induction and paralysis.
Compare and contrast onset, duration, contraindications and special points of sux and roc
Sux: -Dose 1.5mg/kg IV, inubation level paraylsis at 45-60 seconds and duration of 6-10 minutes
Roc: 1.2mg/kg, intubation level paralysis 45-60 seconds an duration approx 45 minutes, relative contraindiation is a predicted difficult ariway given duatrion of paralysis however can be reveresed with suggamadex
Discuss advantages and disadvantages of tracheostomy placement vs ETT
Tracheo
-Advantages:
- Ease of replacement
- Speech, mobility and swallowing encahnges
- Patient can be nursed outside of ICU
- Ease of suctioning
- patient comfort
Disadvantages
- Complications at cuff site
- stomal complications
- possible contribution to ultimate laryngeal injury
- tracheoinominate artery fistula formation
- possible increase in pulmonary infection
- access to mediastinum by infectious agents after local surgery
- high mortality for inadvertent deccnulation before tract formation
Intuabtion
Advantage
- Rapid insertion by skilled consultant in most setting
- lack of need for surgical procedure
- lack of stomal complications
Disadvantages
- Complications at cuff site
- larygneal complications
- replacement requires skill at all times
- generally requires ICU level supervision
- injuries at nose or mouth
Discuss early and late complications of tracheostomy
Early
- Obstruction: percutaneous tracheostomy tubes can become obstructed by the posterior membranous trachea following intial placement
- Subcut epmpysema and pneumo
- Haemorrage
Late
- Tracheal stenosis and malacia
- Tracheoarterial fistula (life threatening usualy to the inoinate artery)
- Rare now but if occurs
- Over inflate the tacheostomy balloon
- Place ETT below level of stoma
- place finger through stoma to apply pressure and stop bleed
- Reduced phonation
- Tracheo-oesophageal fistula
Describe how pulse ox works
- Two wavelengths are used (660 and 940)
Deoxy absorbs more light at 660nm and oxy absorbs more light at 940nm
2) BEER law - the concentration of a given solute in a solvent is determined by the amount of light that is absorbed at a specific wavelength. ie. the concentration of oxy and deoxy can be determined from their absorption of the two wavelengths
3) Determination of pulsatile signal
- absorption over time signal from arterial blood is pulsatile whereas signal from venous hb and tissue is not
- when the ateries pulsate the distance travelled by light through them changes
- one can therefore use Lamberts law (equal parts in the same absorbing medium absorb equal fraction of the light that enter them)
- Thus one can compare the ratio of pulsatile and nonpulsatile absorbance to produce R the ratio of absorbance at any given time
4) Calibration with emperically measured data
- R is meaningless unless it can be related to o2 sats
- a series of saturation measurements and R values have been collected from healthy individuals in the 100-75% sat range and extrapolate to 0%
- This array of data is used by the pulse ox control circuit as a lookup table to p
Describe the normal capnography graph
Phase 1 is the inspiratory baseline which is due to inspired gas with low level of CO2
Phase 2 is the beginning of expiration which occurs when the anatomical dead space and alveolar gas from the alveolir/bronchiolies transition
- the transition from phase 2-3 is the alpha angle
- the alpha angle can be used to assess the VQ of the lung. VQ mismatch will have an alpha angle greater than 90 degrees
Phase 3 the alveolar plateau where the last of the alveolar gas is sampled. This is normally the PET co2
- the transition from phase 3 to 0 is the beta angle
- the beta angle can be used to assess rebreathing. If this occurs the gnle is greater than 90 degrees
Phase 0 reflecting the inspiratory downstroke and the beginning of respiration
Discuss trouble shooting a tracheostomy patient
Approach is same as any intubated patient
DOPES
- Dispalcement of the tube
- Obstruction of the tube
- Patient - especially pneumo, PE pulomnary oedema, collapse and bronchospasm
- Equiptment
- Stacked breaths
Approach
- ABCD- CPR if necessary and call appropriate team as per patient
- Administer high flow to both mouth and stoma site (if laryngectomy nil need for o2 to the nose)
- Remove the inner cannula and chekc if tube is patient or dispalced
- Pass a suction catheter down and suction
- If unable to pass than tube is either blocked or dispalced
- If able to passs thant the tube could still ahve parital blockage
- Only replace tracheostomy if >7 days if not call ENT
- If blocked tube
- Remove tracheostomy
- Attempt to oxygentate and ventilate via the mougth
- if unsuccessful attempt via the stoma
- If unsuccessful intubate past the stoma if larynx intact
- If unsuccessful intubation the stoma
List limitations of pulse ox
- ambient light
- inevitable difference with ABG ox due to processing artifact
- Inability to detct po2 or discrimintate between HB sepcies e.g carboxyhaemoglobin
- Spurius resuts in the presence of CO or MetHB
- Errors to detect pulse with poor perfusion non pulstaile ECMO flow or patient movement
- Increasing inaccuracy in the extrapolated range of calibration values
List requirements for extubation
- Basic preconditions
- Resolution of conditions which had required the intubation and venttilation
- Patient directed mode of ventilation (PSV)
- HD stable
- Adequate muscles strength
2) Airway protection
- able to follow commands
- good cough reflex on suctioning
good gag on oropharyngeal suctioning
3) gas exhange
- spo2 >90% on fio2 <40%
- normal acid base status
4) Lung mechanics
- Peep <8
- good TV 5ml/kg
- VA 10ml/kg
