Post-Extubation Stridor & Laryngeal Oedema

Quick Answer

Post-extubation stridor (PES) is inspiratory stridor occurring within 72 hours of extubation, caused by laryngeal oedema from endotracheal tube (ETT)-induced mucosal injury. Incidence is 6-15% of extubated ICU patients, with reintubation required in 10-40% of those developing stridor. Risk factors include female sex, prolonged intubation (greater than 36-48 hours), large ETT (greater than 8.0 mm), traumatic/difficult intubation, head/neck surgery, and high cuff pressures. The cuff leak test (CLT) predicts risk: absent or low leak (less than 110 mL or less than 12% of tidal volume) indicates high risk, though sensitivity is limited (56-85%). Prevention with prophylactic corticosteroids (methylprednisolone 20-40 mg q4-6h or dexamethasone 5 mg q6h for 12-24 hours pre-extubation) reduces stridor by 50% and reintubation by 50% in high-risk patients (NNT 6-8). Management includes nebulised adrenaline (5 mL of 1:1000), heliox (70:30 or 80:20), systemic corticosteroids, and NIV for mild-moderate stridor. Reintubation is required for severe/progressive stridor with hypoxia; use a smaller ETT (1-2 sizes down), prepare for difficult airway, and have surgical airway backup. Long-term complications include subglottic stenosis (1-4%) and voice changes. [1,2,3]

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CICM Exam Focus

Written Exam (SAQ/MCQ)

High-Yield Topics:

• Definition and timing of post-extubation stridor (within 72 hours)
• Risk factors: female sex, prolonged intubation, large ETT, difficult intubation, head/neck surgery
• Cuff leak test: technique, interpretation, quantitative vs qualitative, limitations
• Prophylactic corticosteroids: evidence base (Francois, Darmon, Jaber meta-analysis), timing (12-24 hours), dosing
• Management algorithm: nebulised adrenaline, heliox, steroids, NIV, reintubation criteria
• Reintubation approach: smaller tube, difficult airway preparation, surgical airway readiness
• Differential diagnosis: anaphylaxis, angioedema, vocal cord paralysis, tracheomalacia
• Long-term complications: subglottic stenosis, voice changes

Common Stem Scenarios:

• "A 52-year-old female is extubated after 6 days of mechanical ventilation for pneumonia. Two hours later she develops stridor and SpO2 drops to 88%. Describe your assessment and management."
• "Discuss the evidence for prophylactic corticosteroids to prevent post-extubation stridor. When would you use them?"
• "Describe the cuff leak test, its interpretation, and limitations."
• "A patient with negative cuff leak test (leak less than 50 mL) is planned for extubation. What is your approach?"

Hot Case Presentation

Typical Scenario: Patient extubated 2-4 hours ago with progressive stridor, using accessory muscles, SpO2 falling despite high-flow oxygen.

Expected Assessment:

• Rapid clinical assessment of severity (stridor audible at rest, accessory muscle use, SpO2)
• Exclude differential diagnoses (anaphylaxis, angioedema, aspiration)
• Immediate treatment initiation while assessing
• Reintubation decision-making and preparation

Viva Extension Points:

• Pathophysiology of laryngeal oedema
• Evidence for CLT predictive value
• Steroid prevention trials
• Heliox mechanism and practical use
• When to proceed to reintubation vs conservative management

Viva/Oral Exam

Expected Knowledge:

• Systematic approach to stridor assessment
• Physiology: Poiseuille's law and airway resistance (resistance proportional to 1/radius^4)
• Evidence-based prevention strategies
• Management algorithm with escalation points
• Reintubation considerations: ETT size, technique, backup plans

Viva Triggers:

• Present cuff leak test result and ask: "Will you extubate this patient?"
• Video of stridor: "What is your differential diagnosis and immediate management?"
• Post-extubation CXR: "What do you see? How does this change your management?"
• "The patient needs reintubation. Describe your approach."

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Key Points

Core Concepts

1. Definition and Timing: [1,4]

   • Post-extubation stridor: High-pitched inspiratory sound from turbulent airflow through narrowed upper airway
   • Laryngeal oedema: Mucosal swelling at glottic/subglottic level
   • Onset: 85% occur within 8 hours of extubation; majority within 2-4 hours
   • Time window: Typically defined as within 72 hours of extubation

2. Incidence and Outcomes: [2,5]

   • Stridor: 6-15% of ICU extubations (higher in high-risk populations)
   • Reintubation for stridor: 10-40% of those developing stridor (1-4% of all extubations)
   • Reintubation mortality: Independent predictor of ICU mortality (OR 7-12)
   • Post-extubation stridor increases ICU LOS by 5-10 days

3. Risk Factors (Mnemonic: LARGE TUBE): [6,7,8]

   • Large ETT (greater than 8.0 mm ID, or ETT:laryngeal diameter ratio greater than 45%)
   • Attempts at intubation (greater than 1 attempt/traumatic intubation)
   • Repeat intubation/self-extubation
   • Gender female (smaller airway diameter, 30-40% higher risk)
   • Extended intubation (greater than 36-48 hours, especially greater than 6 days)
   • Tracheobronchial suctioning (frequent, traumatic)
   • Upper airway surgery/head and neck procedures
   • Balloon cuff pressure (greater than 25-30 cmH2O)
   • Excessive patient agitation/tube movement

4. Cuff Leak Test (CLT) Interpretation: [9,10,11]

   • Positive test (high risk): Cuff leak volume less than 110 mL or less than 12-24% of tidal volume
   • Negative test (low risk): Cuff leak volume greater than 110 mL or greater than 24% of tidal volume
   • Sensitivity: 56-85% (moderate)
   • Specificity: 72-99% (good)
   • Negative predictive value: 94-98% (good cuff leak strongly suggests low risk)
   • Positive predictive value: 20-50% (poor - many positive tests do not develop stridor)

5. Prevention with Corticosteroids: [12,13,14]

   • Prophylactic steroids reduce stridor by 50% and reintubation by 50% (NNT 6-8)
   • Timing: Start 12-24 hours before planned extubation (minimum 4 hours)
   • Regimen options:
     • Methylprednisolone 20-40 mg IV q4-6h for 4 doses
     • Dexamethasone 5 mg IV q6h for 4 doses (24 hours)
   • Indication: High-risk patients (positive CLT or clinical risk factors)
   • Multiple doses superior to single dose

6. Management Algorithm: [15,16]

   • Mild stridor (stable SpO2 greater than 95%): Nebulised adrenaline 5 mL 1:1000, IV steroids, observe
   • Moderate stridor (SpO2 90-95%): Repeat nebulised adrenaline q20-30min, heliox 70:30 or 80:20, consider NIV
   • Severe stridor (SpO2 less than 90%, exhaustion): Prepare for reintubation, continue adrenaline/heliox, call for senior help
   • Reintubation criteria: Progressive hypoxia, exhaustion, reduced consciousness, failed medical management

7. Reintubation Considerations: [17,18]

   • Use smaller ETT (1-2 sizes down from original)
   • Video laryngoscopy preferred
   • Prepare for difficult airway (supraglottic airway, surgical airway kit)
   • Awake intubation if patient stable enough
   • Have experienced operator and surgical backup immediately available
   • Consider tracheostomy if repeat extubation failure anticipated

8. Long-Term Complications: [19,20]

   • Subglottic stenosis: 1-4% of prolonged intubation (greater than 10-14 days)
   • Voice changes/dysphonia: 5-15%
   • Granuloma formation: 1-5%
   • Chronic laryngeal dysfunction: 2-10%

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Red Flags

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Definition and Classification

Post-Extubation Stridor

Definition: Inspiratory stridor occurring after removal of an endotracheal tube, indicating upper airway obstruction at or near the glottic/subglottic level. [1,4]

Timing Classification:

• Immediate (less than 1 hour): Most concerning, often severe oedema
• Early (1-8 hours): Peak incidence window
• Delayed (8-72 hours): Less common, may indicate progressive oedema or other pathology

Severity Grading:

Laryngeal Oedema

Definition: Mucosal and submucosal swelling of the laryngeal structures (epiglottis, aryepiglottic folds, arytenoids, vocal cords, subglottic region) resulting from endotracheal tube-induced injury. [21,22]

Anatomical Distribution:

• Supraglottic: Epiglottis, aryepiglottic folds - less common from ETT
• Glottic: Vocal cords, arytenoids - common site of contact injury
• Subglottic: Most common site of significant oedema (narrowest part of adult airway with complete ring of cricoid cartilage)

Relationship to Stridor:

• Stridor is the clinical manifestation of laryngeal oedema
• Not all laryngeal oedema causes stridor (requires greater than 25-50% lumen reduction)
• Stridor audible when lumen reduced to less than 5 mm diameter (Poiseuille's law: resistance proportional to 1/r^4)

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Risk Factors

Patient Factors

Female Sex: [6,7,23]

• 30-40% higher risk than males
• Smaller laryngeal diameter (16.5 mm vs 18.5 mm male average)
• Smaller cross-sectional area (proportionally larger ETT relative to airway)
• Hormonal factors (oestrogen effects on mucosal reactivity)

Age Extremes: [24]

• Elderly: Fragile mucosa, reduced tissue resilience, more comorbidities
• Young adults: Higher metabolic rate, potentially more reactive inflammation

Medical Comorbidities: [7,8]

• Diabetes mellitus (impaired healing, microvascular disease)
• Obesity (difficult intubation, larger ETT required)
• Immunocompromised states (altered inflammatory response)
• Chronic kidney disease (fluid overload, tissue oedema)
• Cardiac failure (generalised oedema)

Intubation Factors

Endotracheal Tube Size: [6,25]

• Critical threshold: ETT greater than 8.0 mm in females, greater than 9.0 mm in males
• ETT:laryngeal diameter ratio: Greater than 45% increases risk substantially
• Recommendation: Use smallest ETT compatible with adequate ventilation
• Female: 7.0-7.5 mm generally appropriate
• Male: 8.0-8.5 mm generally appropriate

Difficult/Traumatic Intubation: [7,26]

• Greater than 1 intubation attempt: OR 2.5-4.0 for stridor
• Traumatic intubation: Direct mucosal injury, haematoma formation
• Use of stylet/bougie: Potential for posterior commissure injury
• Blind nasotracheal intubation: Higher trauma rate

Self-Extubation/Re-intubation: [27]

• Repeated mucosal injury
• Potential cuff inflation before positioning confirmed
• Agitation-associated movement and trauma

Duration Factors

Duration of Intubation: [5,28,29]

• Less than 24-36 hours: Low risk (~3-5%)
• 36-72 hours: Moderate risk (~8-12%)
• 3-6 days: Higher risk (~10-15%)
• Greater than 7 days: Highest risk (~15-25%)
• Risk increases approximately linearly with duration after first 36 hours

Mechanism:

• Continuous pressure on mucosa causes ischaemia
• Inflammatory response develops over 24-48 hours
• Granulation tissue formation begins day 3-7
• Early fibrosis and stenosis risk after 10-14 days

Cuff-Related Factors

Cuff Pressure: [30,31]

• Target: 20-30 cmH2O (below capillary perfusion pressure of ~30 cmH2O)
• High-risk threshold: Greater than 30 cmH2O causes mucosal ischaemia
• Very high pressure (greater than 40 cmH2O): Significant injury within hours
• Modern high-volume, low-pressure cuffs reduce (but do not eliminate) risk

Cuff Type:

• High-volume, low-pressure (HVLP): Standard, lower mucosal pressure
• Low-volume, high-pressure (LVHP): Obsolete, higher injury risk
• Subglottic secretion drainage: May reduce VAP but tube is larger

Procedural Factors

Head and Neck Surgery: [32,33]

• Thyroid surgery: Risk of RLN injury, local tissue oedema
• Anterior cervical spine surgery: Direct airway compression possible
• Carotid surgery: Haematoma, local swelling
• Maxillofacial surgery: Direct airway involvement

Gastric Surgery: [34]

• Trans-oesophageal procedures
• Increased gastric reflux and aspiration potential
• Position-related tube movement

Patient Movement/Agitation: [35]

• Tube movement against mucosa
• Cuff displacement
• Inadequate sedation/analgesia

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Pathophysiology

Mechanism of Injury

1. Mechanical Pressure Injury: [21,22,36]

The endotracheal tube exerts direct pressure on the laryngeal and tracheal mucosa:

Pressure Points:

• Posterior glottis: Vocal process of arytenoid cartilages
• Subglottic region: Narrowest point, complete cricoid ring prevents expansion
• Tracheal wall: At cuff level

Tissue Response:

• Mucosal compression → reduced capillary blood flow
• Capillary perfusion pressure: ~30 mmHg (25-32 mmHg)
• Cuff pressures greater than 30 cmH2O cause ischaemia
• Ischaemia-reperfusion injury amplifies damage

2. Inflammatory Cascade: [37,38]

Following initial mechanical injury:

Mechanical injury → Cellular damage → Release of DAMPs
                                           ↓
                  Activation of inflammatory pathways
                                           ↓
              Neutrophil recruitment (within 4-6 hours)
                                           ↓
                   Release of pro-inflammatory cytokines
                   (IL-1β, IL-6, TNF-α, IL-8)
                                           ↓
                        Increased vascular permeability
                                           ↓
                      MUCOSAL AND SUBMUCOSAL OEDEMA

Timeline:

• 0-6 hours: Acute inflammation, neutrophil infiltration
• 6-24 hours: Peak oedema formation
• 24-72 hours: Maximal clinical manifestation of stridor
• 3-7 days: Resolution begins (if no ongoing injury)
• Greater than 7-14 days: Risk of granulation and fibrosis

3. Ischaemia-Reperfusion Injury: [39]

Cuff inflation creates cyclical ischaemia:

• Inflation: Mucosal blood flow reduced/stopped
• Deflation: Reperfusion with reactive oxygen species generation
• Repeated cycles amplify oxidative tissue damage

4. Oedema Formation: [40,41]

Factors promoting oedema:

• Increased capillary permeability (inflammatory mediators)
• Hydrostatic pressure changes
• Reduced lymphatic drainage (tissue compression)
• Positive fluid balance common in ICU patients

Starling Forces in Laryngeal Oedema:

• Increased capillary hydrostatic pressure (inflammation, fluid overload)
• Decreased capillary oncotic pressure (hypoalbuminemia)
• Increased interstitial oncotic pressure (protein leak)
• Increased capillary permeability (damaged glycocalyx)

Anatomical Considerations

Why the Subglottic Region is Vulnerable: [42]

1. Narrowest point in adult airway: ~16-18 mm diameter at rest
2. Complete cartilage ring: Cricoid is only complete ring - oedema cannot expand outward
3. Loose submucosa: Pseudostratified ciliated columnar epithelium with loose connective tissue allows significant oedema accumulation
4. Limited collateral circulation

Poiseuille's Law Application: [43]

Resistance to airflow through a tube:

R = 8ηL / πr⁴

Where:
R = Resistance
η = Viscosity of gas
L = Length of tube
r = Radius of tube

Clinical Implication:

• 1 mm of oedema in 10 mm diameter airway:
  • Reduces radius from 5 mm to 4 mm (20% reduction)
  • Increases resistance by (5/4)⁴ = 2.4 fold (144% increase)
• 2 mm of oedema:
  • Reduces radius from 5 mm to 3 mm (40% reduction)
  • Increases resistance by (5/3)⁴ = 7.7 fold (670% increase)

This explains why apparently minor oedema causes dramatic symptoms

Progression to Stridor

Stridor Threshold:

• Normal adult glottic aperture: ~15-20 mm
• Stridor begins: Lumen reduced to ~5-6 mm diameter
• Critical obstruction: Lumen less than 4 mm

Stridor Characteristics by Level:

• Supraglottic: Low-pitched, "snoring" quality
• Glottic: Variable pitch, position-dependent
• Subglottic: High-pitched, predominantly inspiratory
• Biphasic stridor: Fixed obstruction (severe oedema or stenosis)

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Cuff Leak Test

Rationale and Physiology

The cuff leak test (CLT) assesses for laryngeal oedema by measuring air leak around a deflated ETT cuff. [9,10,11]

Principle:

• Inflated cuff: No air escapes around ETT
• Deflated cuff: Air can escape through space between ETT and larynx
• Laryngeal oedema: Reduced space for air to escape → reduced leak volume

Technique

Quantitative Method (Preferred): [10,44]

Prerequisites:

1. Patient must not be spontaneously breathing (sedated, controlled ventilation)
2. Patient should be on volume-controlled ventilation
3. Record set tidal volume

Steps:

1. Suction oropharynx and endotracheal tube thoroughly
2. Set ventilator to volume-controlled mode
3. Note set inspiratory tidal volume (VTi)
4. Deflate ETT cuff completely
5. Measure exhaled tidal volume (VTe) over 6 respiratory cycles
6. Calculate average exhaled tidal volume
7. Calculate cuff leak volume: CLV = VTi - average VTe (lowest of 6 values often used)
8. Calculate percentage leak: (CLV / VTi) × 100

Example:

• Set tidal volume (VTi): 500 mL
• Exhaled volumes: 420, 410, 405, 400, 395, 390 mL
• Lowest VTe: 390 mL
• Cuff leak volume: 500 - 390 = 110 mL
• Percentage leak: (110/500) × 100 = 22%

Qualitative Method (Simpler): [45]

1. Deflate cuff
2. Occlude ETT and ventilate patient via bag
3. Listen for air leak around ETT
4. Present: Audible leak = low risk
5. Absent: No audible leak = high risk

Interpretation

Standard Thresholds: [9,10,11]

Predictive Value

Meta-Analysis Data (Ochoa et al.): [46]

Clinical Interpretation:

• Good negative test: Adequate cuff leak (greater than 110 mL) strongly suggests low risk
• Poor positive test: Many patients with low/absent leak do NOT develop stridor
• High false-positive rate limits utility for routine screening

Limitations

Factors Affecting CLT Accuracy: [47,48,49]

1. Patient Factors:

   • Secretions in airway (falsely reduce leak)
   • Cough/movement (artefactual variation)
   • Spontaneous breathing (interferes with measurement)

2. Technical Factors:

   • Cuff not fully deflated
   • ETT position (too high/low)
   • Inconsistent measurement technique
   • Mode of ventilation affects results

3. Pathological Factors:

   • Tracheomalacia (false-positive - collapse reduces leak)
   • Existing laryngeal pathology
   • Large ETT (may have leak despite oedema)
   • Small ETT (may have leak obscuring oedema)

4. Timing:

   • CLT performed far from extubation may not reflect status at extubation
   • Should be performed close to planned extubation (same day)

When to Perform CLT

Recommended Indications: [50]

Not Routinely Recommended:

• Short-term intubation (less than 24 hours)
• Uncomplicated intubation
• No risk factors present
• Resource limitations

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Prevention Strategies

Prophylactic Corticosteroids

Evidence Base: [12,13,14,51,52,53,54]

Landmark Trials

Darmon et al. (1992) - PMID: 1563585: [12]

• Design: RCT, 700 patients
• Intervention: Dexamethasone 8 mg single dose pre-extubation vs placebo
• Result: No significant reduction in stridor or reintubation
• Limitation: Single dose, unselected population, low-risk patients

Francois et al. (2007) - PMID: 17413875: [13]

• Design: Multicentre RCT, 761 patients
• Intervention: Methylprednisolone 20 mg q4h × 4 doses (starting 12h pre-extubation) vs placebo
• Population: High-risk (intubation greater than 36 hours)
• Results:
  • "Stridor: 3.0% vs 22% (RR 0.14, p less than 0.001)"
  • "Reintubation for stridor: 4% vs 8% (p=0.02)"
• Key finding: Multiple doses superior, high-risk population benefits most

Cheng et al. (2006) - PMID: 16751494: [51]

• Design: RCT, 128 patients with positive CLT
• Intervention: Methylprednisolone 40 mg q6h × 4 doses vs placebo
• Results: Stridor 7% vs 30% (p less than 0.001), reintubation reduced
• Key finding: Targeted prevention in CLT-positive patients effective

Jaber et al. (2009) - Meta-analysis - PMID: 19318653: [14]

• Included: 6 RCTs, 1,923 patients
• Results:
  • "Stridor: RR 0.47 (95% CI 0.22-0.99)"
  • "Reintubation: RR 0.44 (95% CI 0.17-1.14)"
• Conclusion: Multiple doses more effective than single dose

Current Recommendations

Who to Treat (High-Risk Patients):

1. Positive cuff leak test (CLV less than 110 mL)
2. Intubation greater than 48 hours with additional risk factors
3. Previous extubation failure due to stridor
4. Traumatic/difficult intubation
5. Female with large ETT (≥8.0 mm)
6. Head and neck surgery

Regimen Options:

Timing Critical:

• Minimum 4 hours before extubation (some effect)
• Optimal 12-24 hours before extubation (best effect)
• Multiple doses superior to single dose

NNT (Number Needed to Treat): [54]

• Prevent stridor: NNT 6-8
• Prevent reintubation: NNT 10-15

ETT Selection and Management

ETT Size Selection: [25,55]

Cuff Pressure Management: [30,31,56]

Target: 20-25 cmH2O (maximum 30 cmH2O)

Monitoring Options:

1. Manual manometry: Check q6-8h
2. Continuous cuff pressure monitoring: Devices available
3. Minimal occlusive volume technique: Inflate cuff until no leak on inspiration

High-Pressure Consequences:

• greater than 30 cmH2O: Mucosal ischaemia begins
• greater than 40 cmH2O: Significant tissue damage within hours
• Persistent high pressure: Ischaemic necrosis, tracheomalacia, stenosis

ETT Position and Stabilisation

Optimal Position: [57]

• Tip 3-5 cm above carina (approximately T2-T4 level)
• At level of medial clavicular heads on CXR
• Too high: Laryngeal injury, accidental extubation
• Too low: Bronchial intubation, cuff damage from carina

Secure Fixation:

• Minimize tube movement
• Use appropriate ties/devices
• Check position after repositioning patient
• Reassess after procedures (prone positioning, turns)

Sedation and Analgesia

Rationale: [35,58]

• Patient movement/bucking causes tube movement against mucosa
• Inadequate sedation → agitation → injury
• Over-sedation → prolonged ventilation → more injury

Balance:

• Adequate analgesia (fentanyl, morphine, remifentanil)
• Appropriate sedation (propofol, dexmedetomidine, midazolam)
• Daily sedation interruption trials
• Target RASS -2 to 0 when approaching extubation

Humidification

Importance: [59]

• Dried secretions traumatize mucosa during suctioning
• Optimal humidification: 33-44 mg H2O/L, 34-41°C
• Heat and moisture exchangers (HME) vs heated humidification
• Heated humidification preferred for prolonged ventilation

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Clinical Presentation

Timing of Onset

Distribution: [4,5]

• Within 1 hour: 15-20%
• 1-4 hours: 40-50% (peak incidence)
• 4-8 hours: 20-25%
• 8-24 hours: 10-15%
• 24-72 hours: 5-10%
• Greater than 72 hours: Rare (consider alternative diagnosis)

Clinical Features

Stridor Characteristics:

• Sound: High-pitched, harsh, "crowing"
• Phase: Predominantly inspiratory (extrathoracic obstruction)
• Volume: Increases with respiratory effort
• Position: May worsen supine, improve sitting

Associated Symptoms:

• Dyspnoea/air hunger
• Voice changes (hoarseness, muffled)
• Difficulty swallowing/drooling
• Sensation of throat tightness
• Anxiety/distress

Physical Signs:

Severity Assessment

Westley Croup Score (Adapted for Adults): [60]

Interpretation:

• ≤2: Mild
• 3-7: Moderate
• ≥8: Severe

Practical Severity Classification:

Differential Diagnosis

Must Exclude:

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Management

Initial Assessment and Stabilisation

ABCDE Approach:

A - Airway:

• Assess for stridor quality and severity
• Position patient sitting upright if tolerated
• Suction oropharynx if secretions present
• Call for senior help immediately

B - Breathing:

• Apply high-flow oxygen (15 L/min via non-rebreather or HFNC 40-60 L/min)
• Assess work of breathing
• Monitor SpO2 continuously
• Prepare for assisted ventilation

C - Circulation:

• IV access if not already present
• Monitor for hypotension (may indicate severe hypoxia)
• Prepare resuscitation drugs

D - Disability:

• Assess consciousness (GCS, RASS)
• Altered consciousness indicates severe hypoxia/hypercapnia

E - Exposure:

• Look for signs of anaphylaxis (urticaria, angioedema)
• Check neck for haematoma if post-surgical

Pharmacological Management

Nebulised Adrenaline

Mechanism: [15,61]

• Alpha-1 adrenergic activation → vasoconstriction
• Reduces mucosal blood flow → reduces oedema
• Onset: 10-30 minutes
• Duration: 1-2 hours (short-lived, may rebound)

Dosing:

Nebulised Adrenaline:
- Dose: 5 mL of 1:1000 (5 mg) 
- Alternative: 0.5 mL of 1:1000 per kg, max 5 mL
- Delivery: Via nebuliser with oxygen flow 6-8 L/min
- Frequency: May repeat q20-30 minutes if needed
- Maximum: Usually 3 doses before considering other options

Monitoring:

• Heart rate (expect tachycardia)
• Blood pressure
• ECG if available (arrhythmia risk)
• Clinical response

Cautions:

• Cardiac disease (ischaemia, arrhythmia)
• Hypertension
• Hyperthyroidism
• Rebound effect: symptoms may recur as drug wears off (1-2 hours)

Systemic Corticosteroids

Mechanism: [62]

• Reduce inflammation and oedema
• Stabilise vascular endothelium
• Onset: 4-6 hours (not immediate rescue)
• Optimal as prevention rather than treatment

Dosing:

Note: Corticosteroids are adjunctive, not rescue therapy. They work over hours, not minutes.

Heliox

Mechanism: [63,64]

• Helium is less dense than nitrogen (0.18 vs 1.25 g/L)
• Lower gas density → reduced resistance to turbulent flow
• Turbulent flow in narrowed airway → heliox reduces work of breathing
• Does NOT treat underlying oedema - buys time

Composition:

• 80:20 (helium:oxygen): Maximum benefit, requires SpO2 greater than 92%
• 70:30: Standard mixture, adequate for most patients
• 60:40: Minimum helium concentration with clinical effect

Delivery:

• Requires specialized flow meters (calibrated for heliox)
• Non-rebreather mask at high flow (15 L/min)
• Tight-fitting mask essential (room air dilution negates benefit)

Efficacy:

• Reduces stridor and work of breathing in minutes
• Bridge to definitive management or steroid effect
• No effect on oedema itself

Limitations:

• Requires high helium concentration (FiO2 limited to 20-40%)
• Cannot use if FiO2 requirement greater than 40%
• Specialized equipment needed
• Does not treat cause

Non-Invasive Ventilation

Role in Post-Extubation Stridor: [65,66]

Potential Benefits:

• Positive pressure may stent open airway
• Reduces work of breathing
• Buys time for steroids to work

Risks:

• May delay definitive reintubation
• Not effective for severe/complete obstruction
• Mask seal difficult with respiratory distress

When to Consider:

• Moderate stridor with preserved consciousness
• SpO2 maintainable greater than 90%
• Not for severe stridor or impending respiratory failure

Settings:

• CPAP 5-10 cmH2O, or
• BiPAP: IPAP 10-15, EPAP 5-8 cmH2O
• FiO2 as required

High-Flow Nasal Cannula

Role: [67]

• Provides heated humidified high-flow oxygen
• Generates low-level positive pressure (2-5 cmH2O)
• Better tolerated than NIV for some patients

Settings:

• Flow 40-60 L/min
• FiO2 as required
• Temperature 31-37°C

Reintubation Decision

Indications for Reintubation: [17,18]

Decision Framework:

1. Is the patient deteriorating despite medical management?
2. Are there signs of exhaustion or impending arrest?
3. Can the patient protect their airway?
4. Is the trajectory improving or worsening?

Key Principle: Better to reintubate early in controlled fashion than emergently during arrest.

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Reintubation Considerations

Pre-Intubation Preparation

Team:

• Most senior available airway operator
• Surgical/ENT backup on standby
• Second capable airway operator
• Experienced assistant

Equipment:

Drugs:

• Induction agent (ketamine preferred - maintains spontaneous ventilation)
• Neuromuscular blocker (rocuronium or suxamethonium)
• Vasopressors (push-dose phenylephrine 100 mcg)
• Sugammadex (if rocuronium used - can reverse paralysis if CICO)

Approach

Preferred Technique: [17,68]

1. If patient stable enough: Consider awake fibreoptic intubation

   • Maintains spontaneous ventilation
   • Diagnostic and therapeutic
   • Allows assessment of oedema severity

2. If patient unstable/unable to cooperate:

   • Rapid sequence intubation with modifications
   • Ketamine preferred induction agent (maintains respiratory drive longer)
   • Video laryngoscopy first-line
   • Smaller ETT (1-2 sizes down)

Tube Selection:

Original ETT 8.0 mm → Reintubation with 6.5-7.0 mm
Original ETT 7.5 mm → Reintubation with 6.0-6.5 mm
Original ETT 7.0 mm → Reintubation with 5.5-6.0 mm

Rationale for Smaller Tube:

• Oedematous airway is narrower
• Easier to pass through swollen glottis
• Can be exchanged for larger tube once oedema resolves

Awake Intubation Technique

When to Consider: [69]

• Predicted difficult airway
• Patient cooperative
• Not in extremis
• Time available for preparation

Technique:

1. Topicalize airway (lidocaine spray, nebulised lidocaine)
2. Light sedation (dexmedetomidine, small-dose ketamine)
3. Insert fibreoptic scope through mouth or nose
4. Visualize and assess oedema
5. Advance scope through oedematous glottis
6. Railroad ETT over scope
7. Confirm placement, then provide full sedation

Failed Intubation - Escalation

Plan A: Oral Intubation

• Video laryngoscopy, optimized position
• Bougie if poor view
• Maximum 3 attempts

Plan B: Supraglottic Airway

• i-gel or LMA Supreme
• If oxygenating, can attempt fibreoptic-guided intubation through SGA
• Maximum 3 attempts

Plan C: Front of Neck Access

• Cannot Intubate, Cannot Oxygenate (CICO)
• Scalpel cricothyroidotomy
• Do not delay if SpO2 falling and cannot oxygenate

CICO and Surgical Airway

Recognition of CICO: [70,71]

• Failed intubation (3 attempts)
• Failed SGA ventilation (3 attempts)
• SpO2 falling
• Cannot oxygenate patient

Scalpel Cricothyroidotomy Technique:

1. Identify landmarks: Cricothyroid membrane (below thyroid cartilage, above cricoid)
2. Horizontal stab incision through skin and membrane
3. Turn scalpel 90° and slide caudally to keep tract open
4. Insert bougie through incision
5. Railroad 6.0 mm cuffed ETT or tracheostomy tube over bougie
6. Remove bougie, inflate cuff, confirm ventilation

Emergency Equipment:

• Scalpel (No. 10 or 20 blade)
• Bougie
• 6.0 mm cuffed tube (ETT or tracheostomy)

Post-Reintubation Management

1. Confirm tube placement (EtCO2, auscultation, CXR)
2. Secure ETT meticulously
3. Sedation to prevent agitation/self-extubation
4. Continue corticosteroids
5. Minimize cuff pressure (20-25 cmH2O)
6. Use smallest effective tube
7. Plan for delayed extubation (48-72 hours minimum)
8. Consider ENT/airway assessment before next extubation
9. Consider tracheostomy if repeated failure anticipated

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Long-Term Complications

Subglottic Stenosis

Incidence: 1-4% of prolonged intubation (greater than 10-14 days) [19,72,73]

Pathophysiology:

1. Mucosal ulceration (acute)
2. Granulation tissue formation (days 3-7)
3. Fibrosis and scar contracture (weeks 2-6)
4. Mature stenosis (months)

Risk Factors:

• Prolonged intubation greater than 10-14 days
• High cuff pressures
• Repeated intubations
• Traumatic intubation
• Infection
• Diabetes mellitus
• Systemic corticosteroid use (impairs healing)

Presentation:

• Dyspnoea on exertion (early)
• Stridor on exertion progressing to rest
• Voice changes
• Recurrent "asthma" or "bronchitis"
• May present weeks to months after ICU discharge

Classification (Cotton-Myer): [74]

Management:

• Grade I-II: Observation, may resolve, serial endoscopy
• Grade II-III: Endoscopic dilation, laser therapy, steroid injection
• Grade III-IV: Surgical resection and reconstruction, tracheostomy

Voice Changes and Dysphonia

Incidence: 5-15% post-prolonged intubation [75,76]

Causes:

• Vocal cord oedema
• Vocal cord paralysis (arytenoid dislocation, RLN injury)
• Granuloma formation at posterior commissure
• Subglottic web formation

Presentation:

• Hoarseness
• Weak voice
• Vocal fatigue
• Breathy voice
• Change in pitch

Assessment:

• Flexible nasopharyngoscopy
• Speech pathology assessment
• Videostroboscopy

Management:

• Speech therapy
• Voice rest (initial)
• Surgical excision of granuloma if required
• Treatment of vocal cord paralysis (injection, medialization)

Granuloma Formation

Incidence: 1-5% [77]

Location: Typically posterior commissure (contact point of ETT)

Presentation:

• Voice changes
• Throat clearing
• Globus sensation
• May cause stridor if large

Management:

• Voice therapy (reduce trauma from throat clearing)
• Surgical excision if symptomatic

Arytenoid Dislocation

Incidence: Rare (0.1-1%) [78]

Mechanism: Traumatic intubation, ETT positioning

Presentation:

• Hoarseness
• Aspiration
• Stridor (if bilateral)

Diagnosis: Laryngoscopy shows asymmetric arytenoids

Management:

• ENT assessment
• Closed reduction (early)
• Open surgical repair

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Australian and New Zealand Context

ANZICS-CORE Data

Post-Extubation Stridor Epidemiology: [79]

• Limited specific Australian registry data on post-extubation stridor
• Extubation failure (all causes): ~10-15% in Australian ICUs
• Reintubation associated with 2-3 fold increase in mortality

Practice Patterns:

• Variable use of cuff leak test across units
• Increasing adoption of prophylactic steroids for high-risk patients
• Video laryngoscopy widely available in Australian ICUs

CICM Guidelines and Standards

CICM IC-Series Guidelines:

• IC-1 (Minimum Standards for ICU): Airway management equipment requirements
• IC-7 (Intensive Care Transport): Airway considerations for transport

Relevant Professional Standards:

• CICM-ANZCA PS57: Guidelines on airway management
• Australian Difficult Airway Guidelines incorporated in practice

Therapeutic Guidelines Australia

eTG Complete Recommendations:

• Corticosteroid use for post-extubation stridor prevention
• Nebulised adrenaline dosing in upper airway obstruction
• Antibiotic prophylaxis not routinely recommended

Indigenous Health Considerations

Aboriginal and Torres Strait Islander Peoples: [80,81]

Relevant Factors:

• Higher rates of respiratory disease requiring ICU admission
• Increased rates of difficult airway (anatomical variations, obesity)
• Higher rates of diabetes (affects healing)
• Geographical barriers to follow-up care
• Language and health literacy considerations

Cultural Safety:

• Involve Aboriginal Health Workers (AHW) and Aboriginal Liaison Officers (ALO)
• Family involvement in decision-making (extended family may have roles)
• Explain procedures in culturally appropriate manner
• Consider need for interpreter services
• Discharge planning must account for remote location access to care

Long-Term Follow-Up:

• Ensure culturally appropriate follow-up arrangements
• Telehealth for remote patients
• Written discharge summary in plain language
• Contact with local health service

Maori Health Considerations (New Zealand)

Te Tiriti o Waitangi Principles:

• Partnership, Participation, Protection
• Involve whanau (extended family) in care decisions
• Respect tikanga (customs) and kawa (protocols)
• Maori Health Workers involvement

Cultural Competence:

• Acknowledge the importance of whanau presence
• Allow for karakia (prayer) if requested
• Understand concepts of tapu (sacred) and noa
• Long-term follow-up considerations for rural Maori communities

Remote and Rural Considerations

Challenges:

• Limited ENT/airway specialist access
• Retrieval may be required for complex cases
• Telemedicine for advice
• Need for definitive local management before transfer

RFDS and Retrieval Services:

• Post-extubation stridor may preclude safe aeromedical transfer
• Consider early intubation if transfer required
• Communicate with retrieval team regarding airway status
• Have backup plans for in-transit deterioration

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SAQ Practice Questions

SAQ 1: Post-Extubation Stridor Assessment and Management

Question: A 58-year-old female is extubated in ICU after 7 days of mechanical ventilation for community-acquired pneumonia. The original ETT size was 7.5 mm. Three hours post-extubation, she develops inspiratory stridor audible at the bedside, with SpO2 93% on 8 L/min oxygen via Hudson mask. She is sitting upright, using accessory muscles, and is anxious but following commands.

Part A (5 marks): List 5 risk factors in this scenario that predispose to post-extubation stridor.

Part B (4 marks): Describe your immediate assessment and initial management of this patient.

Part C (3 marks): The patient improves with initial management but stridor recurs 90 minutes later. What additional therapies would you consider?

Part D (3 marks): The stridor worsens and SpO2 falls to 86%. Discuss your approach to reintubation in this patient.

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SAQ 1: Model Answer

Part A (5 marks): Risk factors for post-extubation stridor (1 mark each, max 5):

1. Female sex - smaller laryngeal diameter, ETT:airway ratio higher
2. Prolonged intubation (7 days) - greater than 48-72 hours increases risk substantially
3. Relatively large ETT (7.5 mm) - at upper limit for female patients (7.0-7.5 mm recommended)
4. Age - 58 years, may have comorbidities affecting tissue resilience
5. Underlying respiratory disease - pneumonia may have caused increased secretions, coughing, tube movement

Additional acceptable answers: any history of difficult intubation, self-extubation, frequent suctioning, high cuff pressures

Part B (4 marks): Immediate assessment and management (1 mark each):

1. Rapid clinical assessment:

   • Severity grading: moderate stridor (at rest, SpO2 90-95%, using accessory muscles)
   • Exclude differentials: anaphylaxis (check for urticaria, angioedema), aspiration (witnessed event)
   • Assess for red flags: level of consciousness, ability to speak, exhaustion

2. Call for senior help and prepare for potential reintubation

3. Optimize oxygenation:

   • Apply high-flow oxygen: HFNC 40-60 L/min, FiO2 0.6-1.0, or non-rebreather 15 L/min
   • Maintain upright positioning

4. Initiate treatment:

   • Nebulised adrenaline 5 mL of 1:1000 (5 mg) via nebuliser
   • IV corticosteroids: Dexamethasone 8-12 mg IV or methylprednisolone 40-125 mg IV
   • Monitor response over 15-30 minutes

Part C (3 marks): Additional therapies for recurrent stridor (1 mark each):

1. Repeat nebulised adrenaline (can repeat q20-30 minutes, typically up to 3 doses)

2. Heliox therapy (70:30 or 80:20 helium:oxygen mixture)

   • Reduces work of breathing due to lower gas density
   • Requires tight-fitting mask and FiO2 requirement less than 40%

3. Non-invasive ventilation (NIV)

   • CPAP 5-10 cmH2O or BiPAP may stent open the airway
   • Use with caution - may delay necessary reintubation

4. Prepare for reintubation - assemble team, equipment, surgical airway backup

Part D (3 marks): Approach to reintubation (1 mark each):

1. Team and preparation:

   • Most senior airway operator available
   • Surgical/ENT backup on standby
   • Prepare difficult airway equipment including cricothyroidotomy kit
   • Prepare induction drugs (ketamine preferred - some maintenance of respiratory drive)

2. ETT selection:

   • Use smaller ETT (1-2 sizes down): 6.0-6.5 mm instead of 7.5 mm
   • Oedematous glottis will be narrower
   • Can upsize once oedema resolves

3. Technique:

   • Video laryngoscopy first-line
   • Have bougie and supraglottic airway immediately available
   • Consider awake fibreoptic intubation if patient cooperative enough
   • Be prepared to proceed directly to surgical airway (CICO scenario)

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SAQ 2: Cuff Leak Test and Prevention Strategies

Question: You are reviewing a 45-year-old male patient who has been intubated for 5 days following polytrauma. He is now ready for extubation. The nursing staff performed a cuff leak test which showed a leak volume of 65 mL (set tidal volume 550 mL).

Part A (4 marks): Describe the technique for performing a cuff leak test and interpret this result.

Part B (4 marks): Discuss the evidence for prophylactic corticosteroids in preventing post-extubation stridor.

Part C (4 marks): What is your management plan for this patient regarding extubation?

Part D (3 marks): The patient is successfully extubated with prophylactic steroids but develops stridor 4 hours later. Outline the key points you would include in a family meeting about the situation.

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SAQ 2: Model Answer

Part A (4 marks): Cuff leak test technique and interpretation:

Technique (2 marks):

1. Patient on volume-controlled ventilation, not spontaneously breathing
2. Suction oropharynx and ETT thoroughly
3. Record set tidal volume (550 mL in this case)
4. Deflate ETT cuff completely
5. Measure exhaled tidal volume over 6 respiratory cycles
6. Calculate: Cuff Leak Volume = Inspiratory VT - Expiratory VT (use lowest of 6 values)
7. Calculate percentage: (CLV/VTi) × 100

Interpretation (2 marks):

• Cuff leak volume: 65 mL
• Percentage: (65/550) × 100 = 11.8%
• Interpretation: POSITIVE test (low leak)
• Thresholds: less than 110 mL or less than 12-24% indicates high risk
• This patient at increased risk of post-extubation stridor (20-35% risk vs 3-5% with adequate leak)
• However, positive predictive value is only 20-50% (many patients with positive CLT do not develop stridor)

Part B (4 marks): Evidence for prophylactic corticosteroids:

Key Trials (2 marks):

1. Francois et al. (2007) PMID: 17413875:

   • 761 patients, multicentre RCT
   • Methylprednisolone 20 mg IV q4h × 4 doses (starting 12h pre-extubation)
   • Stridor: 3% vs 22% (RR 0.14, p less than 0.001)
   • Reintubation for stridor: 4% vs 8%
   • Key finding: Multiple doses superior to single dose

2. Jaber et al. (2009) Meta-analysis PMID: 19318653:

   • 6 RCTs, 1,923 patients
   • Stridor: RR 0.47 (95% CI 0.22-0.99)
   • Reintubation: RR 0.44 (95% CI 0.17-1.14)

Conclusions (2 marks):

• Prophylactic steroids reduce stridor by approximately 50% in high-risk patients
• Multiple doses more effective than single dose
• Timing important: should start 12-24 hours pre-extubation (minimum 4 hours)
• NNT 6-8 to prevent stridor, NNT 10-15 to prevent reintubation
• Benefit greatest in high-risk patients (positive CLT, prolonged intubation)

Part C (4 marks): Management plan:

1. Initiate prophylactic corticosteroids (2 marks):

   • Methylprednisolone 20-40 mg IV q4-6h × 4 doses, OR
   • Dexamethasone 5 mg IV q6h × 4 doses
   • Ideally start 12-24 hours before planned extubation
   • If time-pressured, can start immediately but delay extubation 4+ hours if possible

2. Repeat cuff leak test after steroids (1 mark):

   • May improve with anti-inflammatory effect
   • Better leak (greater than 110 mL) more reassuring but proceed even if still positive

3. Preparation for extubation (1 mark):

   • Ensure experienced staff available
   • Have reintubation equipment ready (smaller ETT, video laryngoscope)
   • Nebulised adrenaline at bedside
   • Consider timing: daylight hours, senior staff available
   • Plan for close monitoring post-extubation (minimum 4-6 hours)

Part D (3 marks): Family meeting key points:

1. Explain the situation clearly:

   • Stridor is swelling of the airway from the breathing tube
   • It is a known complication of being on the ventilator
   • We took preventive measures but it still occurred (not due to error)

2. Explain current management and prognosis:

   • We are treating with medications (adrenaline, steroids)
   • Most cases improve over hours to days
   • We may need to put the breathing tube back if it doesn't improve
   • This would be temporary while the swelling settles

3. Address questions and concerns:

   • Allow time for questions
   • Discuss what to expect over coming hours
   • Explain signs we are monitoring for
   • For Indigenous patients: involve AHW/ALO, allow whanau/family involvement in discussions

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Viva Scenarios

Viva Scenario 1: Post-Extubation Stridor Pathophysiology and Management

Setting: Cross-table viva, 12 minutes (2 minutes reading, 10 minutes discussion)

Candidate Information: You are the ICU registrar on call. A 62-year-old female was extubated 3 hours ago after 8 days of mechanical ventilation for septic shock secondary to cholangitis. Original ETT was 7.5 mm. She has developed stridor and her SpO2 is 91% on 10 L/min oxygen via Hudson mask.

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Examiner-Candidate Dialogue:

Examiner: Tell me what is happening with this patient and why.

Candidate: This patient has post-extubation stridor, which is laryngeal oedema causing upper airway obstruction after removal of the endotracheal tube.

The pathophysiology involves:

1. Mechanical pressure injury: The ETT exerts continuous pressure on the laryngeal and subglottic mucosa. Cuff pressures above capillary perfusion pressure (approximately 30 mmHg) cause mucosal ischaemia.

2. Inflammatory cascade: Mucosal injury triggers an inflammatory response with neutrophil infiltration, cytokine release (IL-1, IL-6, TNF-alpha), increased vascular permeability, and oedema formation.

3. Subglottic vulnerability: The subglottic region is the narrowest part of the adult airway and is surrounded by the cricoid cartilage, the only complete cartilage ring. Oedema cannot expand outward, so it encroaches on the airway lumen.

4. Poiseuille's law: Resistance to airflow is proportional to 1/radius to the fourth power. Small reductions in airway radius cause dramatic increases in resistance. Just 1-2 mm of oedema can increase resistance by 2-8 fold.

This patient has multiple risk factors: female sex, prolonged intubation of 8 days, and a relatively large ETT of 7.5 mm for her gender.

---

Examiner: What are the risk factors for post-extubation stridor?

Candidate: The risk factors can be remembered with the mnemonic "LARGE TUBE":

• L - Large ETT: greater than 8.0 mm, or ETT:laryngeal diameter ratio greater than 45%
• A - Attempts: Multiple intubation attempts, traumatic intubation
• R - Repeat intubation: Self-extubation with reintubation
• G - Gender female: 30-40% higher risk due to smaller laryngeal diameter
• E - Extended duration: greater than 36-48 hours, risk increases with time
• T - Tracheal suctioning: Frequent, traumatic suctioning
• U - Upper airway surgery: Head and neck procedures
• B - Balloon cuff pressure: greater than 25-30 cmH2O
• E - Excessive agitation: Patient movement causing tube trauma

This patient has female sex, prolonged intubation of 8 days, and a 7.5 mm tube which is at the upper limit for females.

---

Examiner: How would you assess the severity of this patient's stridor?

Candidate: I would perform a rapid clinical assessment:

Stridor characteristics:

• At rest or only with exertion (this patient has stridor at rest - concerning)
• Inspiratory (suggests extrathoracic obstruction), expiratory, or biphasic

Work of breathing:

• Accessory muscle use (sternocleidomastoid, scalenes)
• Tracheal tug, intercostal recession
• Tripod positioning

Oxygenation:

• SpO2 91% on 10 L/min is concerning - suggests significant obstruction

Conscious state:

• Alert, anxious but following commands is reassuring
• Altered consciousness would indicate severe hypoxia or hypercapnia

Ability to speak:

• Can speak in sentences (mild) vs phrases (moderate) vs unable to speak (severe)

I would classify this as moderate stridor: stridor at rest, SpO2 90-95%, increased work of breathing but maintaining consciousness.

---

Examiner: Describe your immediate management.

Candidate: I would follow a systematic approach:

Immediate actions:

1. Call for senior help and prepare for potential reintubation
2. Keep patient sitting upright
3. Apply high-flow oxygen - HFNC 40-60 L/min, FiO2 0.8-1.0, or non-rebreather 15 L/min

Pharmacological treatment:

1. Nebulised adrenaline 5 mL of 1:1000 (5 mg) immediately

   • Alpha-1 adrenergic effect causes mucosal vasoconstriction
   • Reduces oedema within 10-30 minutes
   • Duration 1-2 hours, may need to repeat

2. IV corticosteroids:

   • Dexamethasone 8-12 mg IV or methylprednisolone 40-125 mg IV
   • Won't work immediately but will reduce inflammation over 4-6 hours

Prepare for escalation:

1. Prepare difficult airway trolley with smaller ETT (6.0-6.5 mm)
2. Have heliox available if SpO2 permits (FiO2 requirement less than 40%)
3. Alert surgical/ENT team
4. Prepare cricothyroidotomy kit

Exclude differentials:

• Check for urticaria/angioedema suggesting anaphylaxis
• Review recent medications (ACE inhibitor-induced angioedema)
• Check neck for haematoma if relevant surgery

---

Examiner: The patient improves briefly but stridor recurs. What would you do?

Candidate: This is a concerning development as adrenaline has a short duration of action.

Additional therapies:

1. Repeat nebulised adrenaline - can give up to 3 doses at 20-30 minute intervals

2. Heliox therapy:

   • If FiO2 requirement permits (ideally less than 40%)
   • 70:30 or 80:20 helium:oxygen mixture
   • Reduces turbulent flow resistance due to lower gas density
   • Buys time for steroids to work
   • Requires specialized flow meters and tight-fitting mask

3. Consider NIV:

   • CPAP 5-10 cmH2O may stent open the airway
   • Use with caution - should not delay necessary reintubation

4. Lower threshold for reintubation:

   • If not improving after 3 adrenaline doses and heliox
   • If any deterioration in SpO2, consciousness, or exhaustion
   • Better to intubate in controlled fashion than during arrest

---

Examiner: You decide to reintubate. Describe your approach.

Candidate: Given this is a patient with known laryngeal oedema and a difficult airway scenario, I would approach this carefully:

Team:

• Most senior airway operator
• Second capable operator
• Experienced assistant
• Surgical backup on standby

Preparation:

• Video laryngoscope as primary device
• Smaller ETT: 6.0-6.5 mm (not 7.5 mm)
• Bougie, airway exchange catheter
• Supraglottic airway (i-gel)
• Cricothyroidotomy kit opened

Drugs:

• Ketamine for induction (maintains some respiratory drive)
• Rocuronium
• Sugammadex available (can reverse rocuronium if CICO)
• Push-dose phenylephrine for hypotension

Technique options:

1. Awake fibreoptic intubation - if patient cooperative and not in extremis

   • Topicalize with lidocaine
   • Light sedation with dexmedetomidine or low-dose ketamine
   • Allows assessment of oedema and controlled intubation

2. Modified RSI - if patient uncooperative or deteriorating

   • Preoxygenation with HFNC
   • Ketamine induction
   • Rocuronium paralysis
   • Video laryngoscopy first attempt
   • Maximum 3 attempts before moving to SGA then surgical airway

Post-intubation:

• Confirm placement with EtCO2
• Secure tube carefully
• Continue steroids
• Minimal cuff pressure (20-25 cmH2O)
• Plan for delayed re-extubation in 48-72 hours

---

Examiner: How might you have prevented this complication?

Candidate: Prevention strategies include:

Pre-extubation assessment:

• Cuff leak test - identifies high-risk patients (though limited sensitivity)
• Identify clinical risk factors

Prophylactic corticosteroids:

• For high-risk patients (positive CLT, prolonged intubation, female with large ETT)
• Multiple doses: methylprednisolone 20-40 mg q4-6h × 4 doses
• Start 12-24 hours before planned extubation
• Evidence: Francois et al. showed stridor reduction from 22% to 3%

During intubation:

• Use appropriate ETT size (7.0-7.5 mm for females)
• Minimize intubation attempts
• Avoid traumatic intubation

During ventilation:

• Cuff pressure monitoring (target 20-25 cmH2O)
• Adequate sedation to minimize movement
• Minimize duration of intubation (daily weaning trials)
• Good humidification to prevent secretion crusting

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Viva Scenario 2: Cuff Leak Test and Evidence-Based Practice

Setting: Cross-table viva, 12 minutes

Candidate Information: You are reviewing a 55-year-old male intubated for 4 days following cardiac surgery. The team is planning extubation. The cuff leak test shows a leak volume of 45 mL (tidal volume 500 mL).

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Examiner-Candidate Dialogue:

Examiner: How do you interpret this cuff leak test result?

Candidate: This is a positive cuff leak test indicating high risk for post-extubation stridor.

Calculation:

• Cuff leak volume: 45 mL
• Percentage: (45/500) × 100 = 9%
• Threshold for positive test: less than 110 mL or less than 12% of tidal volume
• This patient is below both thresholds

What this means:

• High risk of post-extubation stridor (20-35% vs 3-5% with adequate leak)
• However, positive predictive value is only 20-50%
• Many patients with positive CLT do NOT develop stridor
• The negative predictive value is better (94-98%) - an adequate leak is reassuring

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Examiner: Tell me about the limitations of the cuff leak test.

Candidate: The cuff leak test has several important limitations:

Test performance:

• Sensitivity is moderate: 56-85%
• Positive predictive value is poor: only 20-50%
• This means many positive tests are false positives
• It's better at ruling out risk (good NPV) than ruling it in

Technical factors:

• Requires patient not spontaneously breathing (controlled ventilation)
• Secretions in airway can reduce apparent leak (false positive)
• Cuff must be fully deflated
• ETT position affects results
• No standardized technique across units

Patient factors:

• Tracheomalacia can cause false positive (tracheal collapse reduces leak)
• Large ETT may have leak despite oedema
• Small ETT may have leak even with oedema

Timing:

• CLT reflects status at time of testing
• Should be performed close to planned extubation

Clinical application:

• Most useful when positive in combination with clinical risk factors
• An adequate leak is reassuring
• A positive test warrants consideration of prophylactic steroids, not necessarily delaying extubation

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Examiner: What is the evidence for prophylactic corticosteroids?

Candidate: The evidence supports prophylactic steroids for high-risk patients:

Key studies:

1. Darmon et al. (1992):

• 700 patients, single-dose dexamethasone 8 mg
• No significant benefit
• Limitation: single dose, unselected population

2. Francois et al. (2007) - PMID 17413875:

• This is the landmark positive trial
• 761 high-risk patients (intubation greater than 36 hours)
• Methylprednisolone 20 mg IV every 4 hours × 4 doses, starting 12 hours pre-extubation
• Results:
  • "Stridor: 3% vs 22% (RR 0.14, p less than 0.001)"
  • "Reintubation for stridor: 4% vs 8%"
• Key findings: Multiple doses work; single dose doesn't

3. Cheng et al. (2006):

• 128 patients with positive CLT
• Methylprednisolone 40 mg q6h × 4 doses
• Stridor 7% vs 30% (p less than 0.001)
• Targeted high-risk group benefits most

4. Jaber et al. (2009) Meta-analysis:

• 6 RCTs, 1,923 patients
• Stridor: RR 0.47 (95% CI 0.22-0.99)
• Reintubation: RR 0.44 (not quite significant)
• Confirms benefit of multiple doses

Conclusions:

• Multiple doses required (single dose ineffective)
• Start 12-24 hours before extubation
• Benefit greatest in high-risk patients
• NNT approximately 6-8 to prevent stridor

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Examiner: What is your plan for this patient with a positive cuff leak test?

Candidate: Given the positive CLT in a patient post-cardiac surgery (with additional airway risks), my plan would be:

1. Initiate prophylactic steroids:

• Methylprednisolone 20-40 mg IV every 6 hours × 4 doses, OR
• Dexamethasone 5 mg IV every 6 hours × 4 doses
• Starting now, with extubation planned in 12-24 hours

2. Consider repeating CLT after steroids:

• May show improved leak
• More reassuring but proceed even if still positive

3. Optimize for extubation:

• Ensure minimal cuff pressure (20-25 cmH2O)
• Continue adequate sedation until extubation
• Plan extubation during daylight hours with senior staff available

4. Prepare for potential stridor:

• Nebulised adrenaline at bedside
• Difficult airway equipment including smaller ETT (6.5-7.0 mm)
• Heliox available
• Alert ENT/surgical team of high-risk extubation

5. Close monitoring post-extubation:

• Continuous SpO2 monitoring for 6-8 hours minimum
• Nursing staff aware of stridor risk and escalation plan
• Low threshold for medical review if any concerns

6. Additional considerations for cardiac surgery patient:

• Post-thyroidectomy or neck dissection? (RLN injury risk)
• Perioperative haematoma possible
• Higher than usual cardiovascular risk with adrenaline

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Examiner: The patient is extubated with prophylactic steroids and initially does well, but 6 hours later develops mild stridor with SpO2 95% on 6 L/min. What now?

Candidate: This is mild stridor - stridor on exertion or at rest with maintained oxygenation.

Immediate actions:

1. Review patient at bedside, assess severity
2. Optimize oxygen delivery - increase to HFNC 40-50 L/min or higher flow Hudson mask
3. Keep patient sitting upright
4. Ensure IV access

Treatment:

1. Nebulised adrenaline 5 mL of 1:1000

   • First-line treatment for stridor
   • Onset within 10-30 minutes
   • Duration 1-2 hours

2. Continue systemic corticosteroids

   • Already receiving prophylactic course
   • May add additional doses if not already at maximum

3. Monitoring:

   • Continuous SpO2
   • Reassess every 15-30 minutes
   • Watch for improvement or deterioration

Escalation plan:

• If stridor worsens or SpO2 falls: repeat adrenaline
• Consider heliox if FiO2 permits
• Prepare reintubation equipment
• Alert senior staff and surgical backup

Decision points:

• If improving: continue observation, expect resolution over 24-48 hours
• If stable but persistent: consider heliox, NIV
• If deteriorating: early reintubation before exhaustion or arrest

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Examiner: What are the long-term complications this patient might face?

Candidate: Long-term complications of post-extubation stridor and prolonged intubation include:

1. Subglottic stenosis (1-4%):

• Develops from progression of mucosal injury to granulation tissue and fibrosis
• Usually presents weeks to months after ICU discharge
• Symptoms: exertional dyspnoea, stridor, recurrent "asthma"
• Management: endoscopic dilation, laser therapy, surgical resection

2. Voice changes/dysphonia (5-15%):

• Causes: vocal cord oedema, granuloma, paralysis, arytenoid dislocation
• Presents as hoarseness, weak voice, vocal fatigue
• May require speech therapy or surgical intervention

3. Granuloma formation (1-5%):

• Usually at posterior commissure (ETT contact point)
• Can cause globus sensation, voice changes
• May require surgical excision

4. Chronic laryngeal dysfunction (2-10%):

• Ongoing voice changes
• Swallowing difficulties
• May benefit from ENT follow-up

Follow-up recommendations for this patient:

• Routine follow-up not needed if resolves without reintubation
• If recurrent stridor, difficult weaning, or symptoms at discharge: ENT referral
• Advise patient to seek medical attention if voice changes or breathing difficulties after discharge

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References

Core Evidence

1. Epstein SK. Post-extubation stridor: the tip of the iceberg? Crit Care Med. 2009;37(3):1161-1163. PMID: 19237931

2. Jaber S, Chanques G, Matecki S, et al. Post-extubation stridor in intensive care unit patients. Risk factors evaluation and importance of the cuff-leak test. Intensive Care Med. 2003;29(1):69-74. PMID: 12528025

3. Maury E, Guglielminotti J, Alzieu M, et al. How to identify patients at risk for post-extubation stridor. Crit Care Med. 2004;32(9):1791-1795. PMID: 15343003

4. Wittekamp BH, van Mook WN, Tjan DH, et al. Clinical review: post-extubation laryngeal edema and extubation failure in critically ill adult patients. Crit Care. 2009;13(6):233. PMID: 20017889

5. Kriner EJ, Shafazand S, Engoren M. The association between post-extubation stridor and reintubation. Chest. 2005;128(4):2165-2170. PMID: 16236870

Risk Factors

6. Francois B, Bellissant E, Gissot V, et al. 12-h pretreatment with methylprednisolone versus placebo for prevention of postextubation laryngeal oedema: a randomised double-blind trial. Lancet. 2007;369(9567):1083-1089. PMID: 17413875

7. Miller RL, Cole RP. Association between reduced cuff leak volume and postextubation stridor. Chest. 1996;110(4):1035-1040. PMID: 8874265

8. Sandhu RS, Pasquale MD, Miller K, et al. Measurement of endotracheal tube cuff leak to predict postextubation stridor and need for reintubation. J Am Coll Surg. 2000;190(6):682-687. PMID: 10873003

Cuff Leak Test

9. De Bast Y, De Backer D, Moraine JJ, et al. The cuff leak test to predict failure of tracheal extubation for laryngeal edema. Intensive Care Med. 2002;28(9):1267-1272. PMID: 12209275

10. Ochoa ME, Marin MC, Frutos-Vivar F, et al. Cuff-leak test for the diagnosis of upper airway obstruction in adults: a systematic review and meta-analysis. Intensive Care Med. 2009;35(7):1171-1179. PMID: 19399474

11. Engoren M. Evaluation of the cuff-leak test in a cardiac surgery population. Chest. 1999;116(4):1029-1031. PMID: 10531169

Prevention Strategies

12. Darmon JY, Rauss A, Dreyfuss D, et al. Evaluation of risk factors for laryngeal edema after tracheal extubation in adults and its prevention by dexamethasone. A placebo-controlled, double-blind, multicenter study. Anesthesiology. 1992;77(2):245-251. PMID: 1563585

13. Francois B, Bellissant E, Gissot V, et al. 12-h pretreatment with methylprednisolone versus placebo for prevention of postextubation laryngeal oedema. Lancet. 2007;369:1083-1089. PMID: 17413875

14. Jaber S, Jung B, Chanques G, et al. Effects of steroids on reintubation and post-extubation stridor in adults: meta-analysis of randomised controlled trials. Crit Care. 2009;13(2):R49. PMID: 19318653

Management

15. Moore S, Katz B, Gomes LJ, et al. Nebulized epinephrine for post-extubation stridor in adult patients: systematic review and meta-analysis. Crit Care Med. 2019;47(9):e741-e749. PMID: 31162197

16. Kuriyama A, Umakoshi N, Sun R. Prophylactic corticosteroids for prevention of postextubation stridor and reintubation in adults: a systematic review and meta-analysis. Chest. 2017;151(5):1002-1010. PMID: 28109795

17. Mort TC. Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts. Anesth Analg. 2004;99(2):607-613. PMID: 15271750

18. De Jong A, Molinari N, Terzi N, et al. Early identification of patients at risk for difficult intubation in the intensive care unit. Am J Respir Crit Care Med. 2013;187(8):832-839. PMID: 23348979

Long-Term Complications

19. Stauffer JL, Olson DE, Petty TL. Complications and consequences of endotracheal intubation and tracheotomy. Am J Med. 1981;70(1):65-76. PMID: 7457492

20. Colice GL. Resolution of laryngeal injury following translaryngeal intubation. Am Rev Respir Dis. 1992;145(2 Pt 1):361-364. PMID: 1736742

Pathophysiology

21. Benjamin B. Prolonged intubation injuries of the larynx: endoscopic diagnosis, classification, and treatment. Ann Otol Rhinol Laryngol Suppl. 1993;160:1-15. PMID: 8470867

22. Lindholm CE. Prolonged endotracheal intubation. Acta Anaesthesiol Scand Suppl. 1969;33:1-131. PMID: 4913459

23. Rashkin MC, Davis T. Acute complications of endotracheal intubation. Relationship to reintubation, route, urgency, and duration. Chest. 1986;89(2):165-167. PMID: 3943372

24. Thomas R, Kumar EV, Kameswaran M, et al. Post intubation laryngeal sequelae in an intensive care unit. J Laryngol Otol. 1995;109(4):313-316. PMID: 7782685

25. Honeybourne D, Costello JC, Barham C. Tracheal damage after endotracheal intubation: comparison of two types of endotracheal tubes. Thorax. 1982;37(7):500-502. PMID: 7135283

26. Kastanos N, Estopa Miro R, Marin Perez A, et al. Laryngotracheal injury due to endotracheal intubation: incidence, evolution, and predisposing factors. Crit Care Med. 1983;11(5):362-367. PMID: 6839788

27. Epstein SK, Ciubotaru RL. Independent effects of etiology of failure and time to reintubation on outcome for patients failing extubation. Am J Respir Crit Care Med. 1998;158(2):489-493. PMID: 9700126

28. Colice GL, Stukel TA, Dain B. Laryngeal complications of prolonged intubation. Chest. 1989;96(4):877-884. PMID: 2791687

29. Santos PM, Afrassiabi A, Weymuller EA Jr. Risk factors associated with prolonged intubation and laryngeal injury. Otolaryngol Head Neck Surg. 1994;111(4):453-459. PMID: 7936676

Cuff Pressure

30. Seegobin RD, van Hasselt GL. Endotracheal cuff pressure and tracheal mucosal blood flow: endoscopic study of effects of four large volume cuffs. Br Med J (Clin Res Ed). 1984;288(6422):965-968. PMID: 6423162

31. Nseir S, Duguet A, Copin MC, et al. Continuous control of endotracheal cuff pressure and tracheal wall damage: a randomized controlled study. Crit Care. 2007;11(5):R109. PMID: 17915018

Special Populations

32. Meade MO, Guyatt G, Butler R, et al. Trials comparing early vs late extubation following cardiovascular surgery. Chest. 2001;120(6 Suppl):445S-453S. PMID: 11742965

33. Zieliński J, Gwoźdź G, Nowak D, et al. Thyroid surgery and vocal cord palsy. Langenbecks Arch Surg. 2001;386(6):430-433. PMID: 11735011

34. Lee CH, Peng MJ, Wu CL. Dexamethasone to prevent postextubation airway obstruction in adults: a prospective, randomized, double-blind, placebo-controlled study. Crit Care. 2007;11(4):R72. PMID: 17605780

35. Behbehani NA, Al-Mane F, D'yachkova Y, et al. Myopathy following mechanical ventilation for acute severe asthma: the role of muscle relaxants and corticosteroids. Chest. 1999;115(6):1627-1631. PMID: 10378560

Mechanisms

36. Whited RE. A prospective study of laryngotracheal sequelae in long-term intubation. Laryngoscope. 1984;94(3):367-377. PMID: 6700353

37. Randestad A, Lindholm CE, Fabian P. Dimensions of the cricoid cartilage and the trachea. Laryngoscope. 2000;110(11):1957-1961. PMID: 11081618

38. Hawkins DB. Pathogenesis of subglottic stenosis from endotracheal intubation. Ann Otol Rhinol Laryngol. 1987;96(1 Pt 1):116-117. PMID: 3813374

39. Nordin U. The trachea and cuff-induced tracheal injury. An experimental study on causative factors and prevention. Acta Otolaryngol Suppl. 1977;345:1-71. PMID: 271453

40. Colton House J, Noordzij JP, Murgia B, et al. Laryngeal injury from prolonged intubation: a prospective analysis of contributing factors. Laryngoscope. 2011;121(3):596-600. PMID: 21344442

Heliox and NIV

41. Gupta VK, Cheifetz IM. Heliox administration in the pediatric intensive care unit: an evidence-based review. Pediatr Crit Care Med. 2005;6(2):204-211. PMID: 15730610

42. Frazier MD, Cheifetz IM. The role of heliox in paediatric respiratory disease. Paediatr Respir Rev. 2010;11(1):46-53. PMID: 20113992

43. Epstein SK. Extubation. Respir Care. 2002;47(4):483-492. PMID: 11929620

Techniques

44. Marik PE. The cuff-leak test as a predictor of postextubation stridor: a prospective study. Respir Care. 1996;41(6):509-511. PMID: 10146655

45. Fisher MM, Raper RF. The 'cuff-leak' test for extubation. Anaesthesia. 1992;47(1):10-12. PMID: 1536391

46. Ochoa ME, Marin MC, Frutos-Vivar F, et al. Cuff-leak test for the diagnosis of upper airway obstruction in adults: a systematic review and meta-analysis. Intensive Care Med. 2009;35(7):1171-1179. PMID: 19399474

47. Kriner EJ, Shafazand S, Engoren M. The association between post-extubation stridor and reintubation. Chest. 2005;128(4):2165-2170. PMID: 16236870

48. Chung YH, Chao TY, Chiu CT, Lin MC. The cuff-leak test is a simple tool to verify severe laryngeal edema in patients undergoing long-term mechanical ventilation. Crit Care Med. 2006;34(2):409-414. PMID: 16424722

49. Prinianakis G, Alexopoulou C, Mamidakis E, et al. Determinants of the cuff-leak test: a physiological study. Crit Care. 2005;9(1):R24-31. PMID: 15693962

Guidelines

50. McConville JF, Kress JP. Weaning patients from the ventilator. N Engl J Med. 2012;367(23):2233-2239. PMID: 23215559

51. Cheng KC, Hou CC, Huang HC, et al. Intravenous injection of methylprednisolone reduces the incidence of postextubation stridor in intensive care unit patients. Crit Care Med. 2006;34(5):1345-1350. PMID: 16751494

52. Fan T, Wang G, Mao B, et al. Prophylactic administration of parenteral steroids for preventing airway complications after extubation in adults: meta-analysis of randomised placebo controlled trials. BMJ. 2008;337:a1841. PMID: 18930953

53. Khemani RG, Randolph A, Markovitz B. Corticosteroids for the prevention and treatment of post-extubation stridor in neonates, children and adults. Cochrane Database Syst Rev. 2009;(3):CD001000. PMID: 19588316

54. Kuriyama A, Umakoshi N, Sun R. Prophylactic corticosteroids for prevention of postextubation stridor and reintubation in adults: a systematic review and meta-analysis. Chest. 2017;151(5):1002-1010. PMID: 28109795

Additional References

55. Markovitz BP, Randolph AG. Corticosteroids for the prevention of reintubation and postextubation stridor in pediatric patients: A meta-analysis. Pediatr Crit Care Med. 2002;3(3):223-226. PMID: 12780959

56. Sole ML, Penoyer DA, Su X, et al. Assessment of endotracheal cuff pressure by continuous monitoring: a pilot study. Am J Crit Care. 2009;18(2):133-143. PMID: 19255103

57. Owen RL, Cheney FW. Endobronchial intubation: a preventable complication. Anesthesiology. 1987;67(2):255-257. PMID: 3605752

58. Kress JP, Pohlman AS, O'Connor MF, Hall JB. Daily interruption of sedative infusions in critically ill patients undergoing mechanical ventilation. N Engl J Med. 2000;342(20):1471-1477. PMID: 10816184

59. Ricard JD. Hazards of intubation in the ICU: role of nasal high flow oxygen therapy for preoxygenation and apneic oxygenation to prevent desaturation. Minerva Anestesiol. 2016;82(10):1098-1106. PMID: 27270072

60. Westley CR, Cotton EK, Brooks JG. Nebulized racemic epinephrine by IPPB for the treatment of croup: a double-blind study. Am J Dis Child. 1978;132(5):484-487. PMID: 347921

61. Waisman Y, Klein BL, Boenning DA, et al. Prospective randomized double-blind study comparing L-epinephrine and racemic epinephrine aerosols in the treatment of laryngotracheitis (croup). Pediatrics. 1992;89(2):302-306. PMID: 1734400

62. Rhen T, Cidlowski JA. Antiinflammatory action of glucocorticoids--new mechanisms for old drugs. N Engl J Med. 2005;353(16):1711-1723. PMID: 16236742

63. Myers TR. Use of heliox in children. Respir Care. 2006;51(6):619-631. PMID: 16723038

64. Polaner DM. The use of heliox and the laryngeal mask airway in a child with an anterior mediastinal mass. Anesth Analg. 1996;82(1):208-210. PMID: 8712407

65. Nava S, Gregoretti C, Fanfulla F, et al. Noninvasive ventilation to prevent respiratory failure after extubation in high-risk patients. Crit Care Med. 2005;33(11):2465-2470. PMID: 16276167

66. Ferrer M, Valencia M, Nicolas JM, et al. Early noninvasive ventilation averts extubation failure in patients at risk: a randomized trial. Am J Respir Crit Care Med. 2006;173(2):164-170. PMID: 16224108

67. Hernandez G, Vaquero C, Gonzalez P, et al. Effect of postextubation high-flow nasal cannula vs conventional oxygen therapy on reintubation in low-risk patients: a randomized clinical trial. JAMA. 2016;315(13):1354-1361. PMID: 26975498

68. Cook TM, Woodall N, Harper J, Benger J. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Br J Anaesth. 2011;106(5):617-631. PMID: 21447488

69. Ahmad I, El-Boghdadly K, Bhagrath R, et al. Difficult Airway Society guidelines for awake tracheal intubation (ATI) in adults. Anaesthesia. 2020;75(4):509-528. PMID: 31729018

70. Frerk C, Mitchell VS, McNarry AF, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth. 2015;115(6):827-848. PMID: 26556848

71. Chrimes N. The Vortex: a universal 'high-acuity implementation tool' for emergency airway management. Br J Anaesth. 2016;117 Suppl 1:i20-i27. PMID: 27440673

Long-Term Complications

72. Weymuller EA Jr. Laryngeal injury from prolonged endotracheal intubation. Laryngoscope. 1988;98(8 Pt 2 Suppl 45):1-15. PMID: 3043381

73. Anand VK, Alemar G, Warren ET. Surgical considerations in tracheal stenosis. Laryngoscope. 1992;102(3):237-243. PMID: 1545649

74. Cotton RT, Gray SD, Miller RP. Update of the Cincinnati experience in pediatric laryngotracheal reconstruction. Laryngoscope. 1989;99(11):1111-1116. PMID: 2811546

75. Colton House J, Noordzij JP, Murgia B, et al. Laryngeal injury from prolonged intubation: a prospective analysis of contributing factors. Laryngoscope. 2011;121(3):596-600. PMID: 21344442

76. Tadié JM, Behm E, Lecuyer L, et al. Post-intubation laryngeal injuries and extubation failure: a fiberoptic endoscopic study. Intensive Care Med. 2010;36(6):991-998. PMID: 20232043

77. Karkos PD, George M, Van Der Veen J, et al. Vocal process granulomas: a systematic review of treatment. Ann Otol Rhinol Laryngol. 2014;123(5):314-320. PMID: 24642584

78. Rudert H. Arytenoid dislocation. Ann Otol Rhinol Laryngol. 1994;103(2):154-156. PMID: 8311474

Australian/NZ Context

79. Stow PJ, Hart GK, Higlett T, et al. Development and implementation of a high-quality clinical database: the Australian and New Zealand Intensive Care Society Adult Patient Database. J Crit Care. 2006;21(2):133-141. PMID: 16769456

80. Australian Institute of Health and Welfare. The health and welfare of Australia's Aboriginal and Torres Strait Islander peoples. AIHW Cat. No. IHW 147. Canberra: AIHW; 2015.

81. Wilson D, Barton P. Indigenous hospital experiences: a New Zealand case study. J Clin Nurs. 2012;21(15-16):2316-2326. PMID: 22788565

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Related Topics

Prerequisites

• Weaning from Mechanical Ventilation
• Upper Airway Anatomy
• Difficult Airway in ICU

Related Conditions

• Extubation Failure
• Tracheostomy
• Anaphylaxis in ICU

Differential Diagnoses

• Angioedema
• Upper Airway Obstruction
• Vocal Cord Paralysis

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Last updated: January 2026 Citation Count: 48 PubMed PMIDs