Post-Extubation Stridor

Post-extubation stridor is a harsh inspiratory noise after tube removal from partial upper airway narrowing. It signals airway obstruction at laryngeal or subglottic level.

Epidemiology. It occurs in 1% to 30% of intubated patients, more often after intubation over 36 to 48 hours, in women, in children and after traumatic intubation. Reintubation is needed in about 1% to 10%.

Causes. Laryngeal and subglottic oedema, laryngospasm, vocal cord paralysis, haematoma (neck surgery), tracheomalacia, retained secretions, foreign body, granuloma and anaphylaxis.

Risk factors. Large tube for patient size, prolonged intubation, high cuff pressure, repeated attempts, traumatic intubation, absent cuff leak, fluid overload, female sex, sepsis and head and neck surgery.

Pathophysiology.

Mucosal injury and venous congestion produce oedema in the narrowest part of the airway (the subglottis in children). Resistance rises with the fourth power of radius reduction, so small oedema creates large obstruction.

Inspiratory stridor, hoarseness, tracheal tug, use of accessory muscles, desaturation, anxiety and exhaustion.

Red flags.

• Silent chest, cyanosis or exhaustion.
• Neck swelling after thyroid or carotid surgery.
• Rapid worsening within minutes.
• Drooling or inability to speak.

Clinical. Nasendoscopy or laryngoscopy shows cord movement and oedema. Neck ultrasound or CT when mass effect is suspected. Cuff leak test before extubation (leak under 110 mL or under 24% of tidal volume suggests risk).

Differential diagnosis.

• Laryngospasm.
• Vocal cord paralysis.
• Neck haematoma.
• Foreign body.
• Anaphylaxis.
• Tracheomalacia.
• Bronchospasm.

Sit the patient up, give humidified oxygen, and prepare for reintubation with a difficult airway trolley.

• Adrenaline (nebulised): 5 mg (5 mL of 1 mg/mL) in adults, 0.5 mL/kg of 1 mg/mL (maximum 5 mL) in children; repeat after 15 to 20 minutes; maximum 3 doses in the first hour; monitor heart rate, rhythm and rebound; observe for 2 to 4 hours after the last dose; use caution in ischaemic heart disease.
• Dexamethasone: 8 to 10 mg IV once in adults (0.15 to 0.6 mg/kg in children, maximum 10 mg), repeated every 6 to 8 hours for up to 24 hours; maximum 24 mg daily in adults; monitor glucose; effect appears after 4 to 6 hours.
• Heliox (helium 70% with oxygen 30%): by tight mask until definitive treatment; no maximum duration beyond 24 hours; monitor saturation (limits oxygen delivery); not suitable if oxygen need exceeds 30%.

Reintubate with a smaller tube if stridor is severe or exhaustion develops. Use awake fibreoptic technique if possible. For neck haematoma, open the wound at the bedside and then evacuate surgically.

Prevention. Perform a cuff leak test before extubation in high risk patients, give dexamethasone 4 to 8 mg IV every 6 hours for 12 to 24 hours before planned extubation, use the smallest suitable tube and keep cuff pressure at 20 to 30 cmH2O.

Monitoring. Respiratory rate, work of breathing, saturation and stridor trend every 15 minutes for the first 2 hours.

Referral and escalation. Senior anaesthetic and ENT help immediately for stridor with distress. Critical care admission.

Special groups. Children have a narrow subglottis, so 1 mm oedema reduces cross-sectional area by about 60%.