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Airway

Sheet 08Anaesthesia

Airway

Predicting the difficult airway, awake or asleep, the full stomach, failed intubation and front-of-neck access, airway fire, extubation and the nerves of the larynx.

Cards
19
Minutes
about11
Scenarios
19

Start at card 1Review the rules

Core rulesRead these first2 cards · about 2 min

  1. 01Predicting the difficult airway
  2. 02When oxygenation fails

Predicting the difficult airway

01 / 19

No single bedside sign is reliable; combine them, and weigh history and anatomy most.

Bedside predictors of difficult laryngoscopy

SignDifficult laryngoscopy
Failed jaw protrusion (upper lip bite sign), open its explanationMost sensitive predictor
Mallampati class, open its explanationSecond for sensitivity, 53%
Limited mouth opening, open its explanationMost specific predictor
Thyromental distance under 6 cm, open its explanationPredicts difficulty; abnormal at 6 or 6.5 cm cut‑off
Only soft palate and uvula base seen, open its explanationMallampati class III, fauces hidden (Miller's scheme)
Neck circumference 40 cm or more, obese, open its explanationTop predictor of difficult intubation in obesity
Mallampati III–IV in obesity, open its explanationPositive predictor, second to neck circumference

Mallampati classes (Miller's scheme)

Mallampati class (Miller's scheme)What is seen with the mouth open
Class I, open its explanationSoft palate, fauces, whole uvula and pillars
Class II, open its explanationSoft palate, fauces and part of the uvula
Class III, open its explanationSoft palate and base of the uvula only; fauces hidden
Class IV, open its explanationHard palate only
Threshold, open its explanationClasses III and IV predict a difficult airway

Patient feature

Patient featureDifficult mask ventilation
Beard, open its explanationIndependent predictor with the highest odds ratio
BMI >26, no teeth, age >55, snoring, open its explanationIndependent predictors, five in all with beard

Report a problem with card 1: Predicting the difficult airway

When oxygenation fails

02 / 19

Oxygenate first: facemask, then supraglottic airway; cannot oxygenate means front-of-neck access now.

Point in the failing airwayNext step
Saturation falls under anaesthesia, open its explanation100% oxygen; check expired CO2, tube depth, bilateral breath sounds
Between failed intubation attempts, open its explanationOxygenate by facemask
Intubation declared failed or facemask ventilation inadequate, open its explanationSecond‑generation supraglottic airway, not another attempt
Repeated failed attempts, ventilation worsening, open its explanationStop laryngoscopy; front‑of‑neck access, scalpel preferred
Failed intubation, no oxygenation, open its explanationDeclare emergency; scalpel cricothyroidotomy now, not reversal and waking
Front‑of‑neck access site, open its explanationCricothyroid membrane: between thyroid cartilage above, cricoid below

Report a problem with card 2: When oxygenation fails

Part 1 · DecisionsWhat to do5 cards · about 2 min

  1. 03Awake, or keep them breathing
  2. 04Topicalising the airway
  3. 05The full stomach
  4. 06Laser surgery of the airway
  5. 07Taking the airway out

Awake, or keep them breathing

03 / 19

Predicted difficult or threatened airway: secure it awake or keep breathing, front-of-neck ready.

PatientHow to secure the airway
Cooperative, predicted difficult intubation (small mouth, stiff neck), open its explanationAwake flexible bronchoscope intubation, minimal sedation, not laryngoscope
Ludwig angina, open its explanationBefore anaesthesia: awake fibreoptic (nasal if trismus) or local‑anaesthetic tracheostomy
Tracheal stricture with stridor, open its explanationRigid bronchoscopy in theatre, smaller tube; never standard‑size
Tracheobronchial fistula, open its explanationLung isolation before positive pressure: awake fibreoptic double‑lumen tube
Pierre Robin sequence, awake feasible, open its explanationAwake supraglottic airway or intubation, spontaneous breathing kept
Pierre Robin sequence, awake not feasible, open its explanationSevoflurane induction; videolaryngoscope or fibrescope, never direct laryngoscopy

Report a problem with card 3: Awake, or keep them breathing

The full stomach

05 / 19

Full stomach: rapid sequence induction with a tracheal tube; sedation leaves the airway unguarded.

Full-stomach patient

Full-stomach patientInduction
Unfasted open globe needing urgent repair, open its explanationRapid sequence intubation, rocuronium 1.2 mg/kg; suxamethonium acceptable
Open globe, before laryngoscopy, open its explanationDeep anaesthesia and full blockade first
Bleeding tonsil, treated as full stomach, open its explanationRapid sequence induction, cricoid; etomidate or reduced dose if hypovolaemic
Obese child with symptomatic reflux, open its explanationGeneral anaesthesia (GA) with cuffed tracheal tube, not sedation

Cricoid pressure

Cricoid pressureForce
Awake, then after loss of consciousness, open its explanation10 N awake, 30 N asleep; 44 N obstructs (OAA/DAS)

Report a problem with card 5: The full stomach

Laser surgery of the airway

06 / 19

Laser plus oxygen plus a tube is a fire: lowest oxygen, protected tube, or no tube.

Measure or techniqueWhy
Lowest tolerated oxygen, ceiling 0.3, in air, open its explanationLeast oxidiser; no nitrous oxide
Laser‑resistant tube, dyed‑saline cuff, open its explanationProtected tube; dye reveals a punctured cuff
Saline‑wet gauze, or no tube, open its explanationShields non‑target tissue; tubeless removes the fuel
Injector jet ventilation, open its explanationVenturi entrains room air: more volume, diluted oxygen
Anaesthesia during jet ventilation, open its explanationIntravenous only

Report a problem with card 6: Laser surgery of the airway

Part 2 · RecognitionWhat it is3 cards · about 1 min

  1. 08Croup or epiglottitis
  2. 09Sudden change under anaesthesia: name the cause
  3. 10After neck surgery: name the cause

Sudden change under anaesthesia: name the cause

09 / 19

Name the cause from what changed and when; a clear film rules nothing out.

FindingCause
Rising peak pressure, falling end‑tidal CO2 after gag, open its explanationMouth gag compressing or kinking the tube: check first
Bronchial foreign body, lung over‑inflated beyond it, open its explanationBall‑valve air trapping: avoid nitrous oxide, long expiration
New hypoxaemia after witnessed aspiration, clear chest film, open its explanationAspiration pneumonitis; film changes lag 6 to 12 hours
Desaturation, bilateral crackles after laryngospasm or obstruction, open its explanationNegative‑pressure pulmonary oedema until proven otherwise

Report a problem with card 9: Sudden change under anaesthesia: name the cause

After neck surgery: name the cause

10 / 19

Timing, the neck and the voice name the cause of stridor after neck surgery.

Finding after neck surgeryCause
Stridor over a day after total thyroidectomy, open its explanationHypocalcaemia: secure the airway, then intravenous calcium
Early stridor, swollen neck, open its explanationNeck haematoma
Early stridor, normal neck, open its explanationLaryngeal oedema; bilateral nerve injury if voiceless
Early stridor, normal neck, aphonic, open its explanationBilateral recurrent laryngeal nerve injury: intubate
Hoarseness alone, airway intact, open its explanationUnilateral recurrent laryngeal nerve injury
Tongue deviates after carotid endarterectomy, open its explanationHypoglossal nerve injury, operated side; not recurrent laryngeal

Report a problem with card 10: After neck surgery: name the cause

Part 3 · SituationsWhat now3 cards · about 2 min

  1. 11Airway emergencies: infection, burns, bleeding and trauma
  2. 12Fire in the airway
  3. 13Stridor and laryngospasm after extubation

Airway emergencies: infection, burns, bleeding and trauma

11 / 19

Threatened airway: control the threat first (calm, volume, cuff, oxygen), then secure the airway.

First move in each airway emergency

EmergencyFirst move
Suspected epiglottitis, open its explanationKeep calm and upright; move to theatre
Epiglottitis, induction in theatre, open its explanationSevoflurane, spontaneous breathing kept, then IV, intubate
Smoke inhalation, every victim, open its explanation100% oxygen
Smoke: airway threat or carbon monoxide neurology, open its explanationIntubate early, even with normal saturation
Smoke: soot alone, calm child, open its explanation100% oxygen and observe
Pale or agitated child bleeding after tonsillectomy, open its explanationSecure IV, restore volume (blood if needed), then theatre
Tracheo‑innominate fistula bleeding, open its explanationHyperinflate tracheostomy cuff, then oral tube, then surgery
Unstable neck with airway bleeding: setting, open its explanationTheatre, ear, nose and throat (ENT) surgeon ready
Unstable neck with airway bleeding: technique, open its explanationVideo laryngoscope, in‑line stabilisation; not flexible scope

Report a problem with card 11: Airway emergencies: infection, burns, bleeding and trauma

Stridor and laryngospasm after extubation

13 / 19

Open the airway before drugs: position, continuous positive airway pressure (CPAP), nebulised adrenaline or the wound.

Obstruction after extubation

Obstruction after extubationAction
Post‑extubation stridor, saturation acceptable, open its explanationHumidified oxygen, nebulised racemic adrenaline; steroid adjunct
Desaturation from obstruction or laryngospasm in recovery, open its explanationJaw thrust plus CPAP first, then escalate
Laryngospasm persisting despite jaw thrust, CPAP, deepening, open its explanationSuccinylcholine 4 mg/kg IM without IV; smaller IV dose
Infant laryngospasm with desaturation, open its explanationBradycardia, not tachycardia; break spasm, oxygenate fast
Neck haematoma compromising the airway, open its explanationBedside: cut sutures or clips, evacuate clot; theatre if time

Negative-pressure oedema

Negative-pressure oedemaTreatment
Negative‑pressure pulmonary oedema, any severity, open its explanationOpen airway and oxygen; diuretic (Miller), if overloaded (Barash)
Severe negative‑pressure pulmonary oedema, open its explanationAdd CPAP, positive end‑expiratory pressure (PEEP) or reintubation

Report a problem with card 13: Stridor and laryngospasm after extubation

Part 4 · Conditions and mechanismsWhy it is true5 cards · about 2 min

  1. 14Anatomy that predicts difficulty
  2. 15Nerves of the larynx
  3. 16Supraglottic airways
  4. 17The unexpected full stomach
  5. 18Anaesthesia away from theatre

Anatomy that predicts difficulty

14 / 19

Know which anatomy hinders laryngoscopy and how to position the head and neck.

Patients with a hard laryngoscopy

PatientWhat hinders laryngoscopy
Down syndrome, open its explanationAtlanto‑axial instability; also prepare for difficult laryngoscopy
Down syndrome at intubation, open its explanationKeep neck neutral; avoid excessive flexion or extension
Long‑standing type 1 diabetes, open its explanationStiff joints: expect difficult laryngoscopy
Long‑standing type 1 diabetes before induction, open its explanationExamine jaw and neck movement; check prayer sign
Previous neck radiation, open its explanationDifficult laryngoscopy now, even if earlier intubation easy

Infant airway anatomy

Infant airwayFeature
Infant epiglottis, open its explanationLonger, narrower and stiffer than the adult's
Infant larynx, cricoid and trachea, open its explanationLarynx higher; cricoid narrowest; trachea short

Position for direct laryngoscopy

PositionTechnique
Sniffing position for direct laryngoscopy, open its explanationFlex lower neck, extend atlanto‑occipital joint; never whole neck

Report a problem with card 14: Anatomy that predicts difficulty

Nerves of the larynx

15 / 19

The external superior laryngeal nerve tensions the cords; the recurrent nerve supplies the rest.

Nerve supply and blocks of the larynx

Nerve or blockSupply or territory
External superior laryngeal nerve, open its explanationCricothyroid muscle only
Recurrent laryngeal nerve, open its explanationAll other intrinsic laryngeal muscles and subglottic mucosa
Transtracheal (translaryngeal) block, cricothyroid membrane, open its explanationRecurrent laryngeal nerve: larynx below cords, trachea

Nerve injury

Nerve injuryCord position, voice
Unilateral recurrent laryngeal nerve injury, open its explanationInjured cord fixed near midline, opposite moves: hoarseness, not stridor

Report a problem with card 15: Nerves of the larynx

Supraglottic airways

16 / 19

A laryngeal mask spares the larynx but does not protect against aspiration.

Aspect of the laryngeal maskWhat is true
Airway irritation versus a tube, open its explanationLess sore throat, coughing, bronchospasm, emergence laryngospasm
Placement, open its explanationEasy and quick
Aspiration, open its explanationNot prevented by the laryngeal mask
Classic laryngeal mask, open its explanationReusable silicone; blind insertion; avoid with a full stomach
Child's laryngeal mask size by weight, open its explanation10–20 kg: 2; 20–30 kg: 2.5; 30–50 kg: 3 (manufacturer)
Fastrach intubating laryngeal mask, open its explanationOxygenate first, tube conduit second; blind passage can fail

Report a problem with card 16: Supraglottic airways

The unexpected full stomach

17 / 19

An obstructed or refluxing oesophagus is a full stomach whatever the fasting time.

Condition or drugRisk
Oesophageal obstruction, achalasia or scleroderma dysmotility, open its explanationFull stomach: aspiration, whatever the fasting time
Calcium channel blocker, such as amlodipine, open its explanationReflux risk by convention; genetic evidence disputes it
Weak cough, open its explanationAspiration risk, not reflux risk

Report a problem with card 17: The unexpected full stomach

TrapsCheck these before you finish1 card · about 2 min

  1. 19Traps

Traps

19 / 19

The tempting move is the reflex or the familiar choice; the books name another.

TemptingRight call
Immediate intubation for soot alone, open its explanation100% oxygen, observe; intubate if airway‑threat or carbon monoxide neurology
Sugammadex and wait for awakening, open its explanationDeclare emergency; scalpel cricothyroidotomy immediately
Another laryngoscopy while mask ventilation inadequate, open its explanationSecond‑generation supraglottic airway, oxygenate first
Hypocalcaemia as cause of early stridor, open its explanationNeck swollen: haematoma; else laryngeal oedema; voiceless: bilateral nerve injury
Reopening the wound for late stridor, open its explanationHypocalcaemia: secure the airway, then intravenous calcium
Mallampati ahead of failed jaw protrusion, open its explanationUpper lip bite sign most sensitive, Mallampati second
Saline‑soaked gauze on airway fire, open its explanationStop laser, cut gas flow, pull tube together
Oxygen 0.3 diluted with nitrous oxide, open its explanationLowest tolerated oxygen, ceiling 0.3, in air; no nitrous
Child's age as the croup clue, open its explanationImprovement after nebulised racemic adrenaline favours croup
Bleeding tonsil: gas induction before IV access, open its explanationIV access and volume, blood if needed, before induction
Awake fibreoptic for open globe, normal airway, open its explanationRapid sequence, rocuronium 1.2 mg/kg; suxamethonium acceptable
Laryngeal mask airway (LMA) chosen to prevent aspiration, open its explanationTracheal tube; the LMA does not protect against aspiration
IV access before inhalational induction in epiglottitis, open its explanationCalm upright child; theatre sevoflurane, spontaneous breathing, then IV
Mallampati over neck circumference in obesity, open its explanationNeck circumference ≥40 cm strongest; Mallampati III–IV also predicts
Transfer to theatre for obstructing haematoma, open its explanationBedside wound opening now; theatre first only if time allows
IV steroid first for post‑extubation stridor, open its explanationHumidified oxygen and nebulised racemic adrenaline; steroid as adjunct

Report a problem with card 19: Traps

QuizCheck yourself19 practice scenarios · one to a screen

QuizCheck yourself19 practice scenariosAnswers checked against the books and guidelines.

Sheet 08 · Airway19 / 19

That is Airway, all 19 cards.

Your answers:

Back to the sheets

The 19 rules

One rule per card, in the sheet's order. Tap one to open its card.

Core rulesRead these first

  1. 01 · Predicting the difficult airwayNo single bedside sign is reliable; combine them, and weigh history and anatomy most.
  2. 02 · When oxygenation failsOxygenate first: facemask, then supraglottic airway; cannot oxygenate means front-of-neck access now.

Part 1 · DecisionsWhat to do

  1. 03 · Awake, or keep them breathingPredicted difficult or threatened airway: secure it awake or keep breathing, front-of-neck ready.
  2. 04 · Topicalising the airwayCount every route into one lidocaine total under the ceiling; aim at tongue base to larynx.
  3. 05 · The full stomachFull stomach: rapid sequence induction with a tracheal tube; sedation leaves the airway unguarded.
  4. 06 · Laser surgery of the airwayLaser plus oxygen plus a tube is a fire: lowest oxygen, protected tube, or no tube.
  5. 07 · Taking the airway outRemove a laryngeal mask deep or fully awake; extubate on numbers: vital capacity 10 mL/kg.

Part 2 · RecognitionWhat it is

  1. 08 · Croup or epiglottitisBarking cough that settles with nebulised adrenaline is croup; drooling and toxicity is epiglottitis.
  2. 09 · Sudden change under anaesthesia: name the causeName the cause from what changed and when; a clear film rules nothing out.
  3. 10 · After neck surgery: name the causeTiming, the neck and the voice name the cause of stridor after neck surgery.

Part 3 · SituationsWhat now

  1. 11 · Airway emergencies: infection, burns, bleeding and traumaThreatened airway: control the threat first (calm, volume, cuff, oxygen), then secure the airway.
  2. 12 · Fire in the airwayStop gases and remove the tube together, flood with saline, then reassess and reintubate.
  3. 13 · Stridor and laryngospasm after extubationOpen the airway before drugs: position, continuous positive airway pressure (CPAP), nebulised adrenaline or the wound.

Part 4 · Conditions and mechanismsWhy it is true

  1. 14 · Anatomy that predicts difficultyKnow which anatomy hinders laryngoscopy and how to position the head and neck.
  2. 15 · Nerves of the larynxThe external superior laryngeal nerve tensions the cords; the recurrent nerve supplies the rest.
  3. 16 · Supraglottic airwaysA laryngeal mask spares the larynx but does not protect against aspiration.
  4. 17 · The unexpected full stomachAn obstructed or refluxing oesophagus is a full stomach whatever the fasting time.
  5. 18 · Anaesthesia away from theatreAway from theatre, plan for the setting's expected complications and for airway rescue.

TrapsCheck these before you finish

  1. 19 · TrapsThe tempting move is the reflex or the familiar choice; the books name another.

Review the rules

Bookmarks

All cards

Your answers:

The coverThe end

Explanation

Why

The trap

Sources

In the reference: evidence and cluesReport