Laryngospasm

Airway·~5 min read· Physician-reviewed✓ Sourced · 5

Stem

A 5-year-old boy, 19 kg, who had a cold three weeks ago, has just had an adenotonsillectomy under sevoflurane with an IV in place. He is extubated as he starts to cough and move. Within seconds he has inspiratory stridor, then silence, with his chest sinking and his abdomen rising on each effort. The capnograph is flat, the saturation is falling from 97% to 85%, and the heart rate is 110.

Question

What is happening, and what do you do?

Ideal answer

HeadlineSilent chest, flat capnograph, paradoxical breathing and stridor after extubation: laryngospasm until I prove otherwise. I call for help and start CPAP.

Remove the stimulus and suction the pharynx, the free moves that come first.
Tight-fitting mask, 100% oxygen, continuous positive pressure, jaw thrust, pressing firmly in the laryngospasm notch behind the ramus of the mandible.¹
Propofol 0.5–0.8 mg/kg (10–15 mg), IV, if it has not broken within about 30 seconds or the saturation keeps falling.²
Succinylcholine 0.1–0.5 mg/kg IV, with atropine, if the spasm persists as saturation or heart rate falls; a full 1–2 mg/kg and intubate if severe.³^,2
Without an IV, succinylcholine 3–4 mg/kg IM, no more than 150 mg.⁴

Watch for: once it breaks, breathing, saturation, then pulmonary edema and aspiration before he leaves recovery.

Breaking down the answer

Escalation with time triggers — the commonest airway emergency at emergence; the examiner wants organization (what first, what next), judgment about when to stop waiting and give succinylcholine, and adaptability when there is no IV.
Why CPAP works — partial spasm often yields to positive pressure, which stents the false cords apart; against complete closure it only insufflates the stomach, so I watch whether gas moves. Larson's maneuver, firm pressure between condyle and mastoid, relaxes the cords reflexly through pain.³
Propofol second — it deepens anesthesia within one circulation time; more volatile cannot reach the alveoli through a closed glottis.
Small-dose succinylcholine, then full dose — the small dose relaxes the cords and often avoids reintubation; desaturation or bradycardia means I need a secure airway, not a trial.
Atropine, because he is a child — hypoxia plus succinylcholine is a vagal setup: 0.02 mg/kg with or before it in any infant or small child, at once if bradycardic.³
No IV — intramuscular succinylcholine into the deltoid or tongue base usually takes 2–3 minutes;⁴ intraosseous access is faster if I already need resuscitation.
Deep or awake, never between — stage 2 is when the reflex is most active. A recent URI, secretions, airway blood and passive smoke push me toward awake; a URI within 6 weeks or second-hand smoke each raise the risk up to 10-fold.¹

Follow-up question

The spasm breaks after succinylcholine and he is reintubated. Pink frothy fluid appears in the tube, and his saturation is 88% on 100% oxygen. What is this, and how do you manage it?

Follow-up answer

HeadlineNegative-pressure pulmonary edema from vigorous inspiration against a closed glottis; I tell the surgeon and the team.

Laryngospasm is its commonest cause.⁵ I keep the tube in, apply PEEP of 5–10 cmH2O, suction, and support oxygenation. A chest radiograph separates it from aspiration, and he goes to a monitored bed or PICU. Furosemide only for volume overload, because the edema is driven by transmural pressure and usually resolves in 12–24 hours with PEEP alone.⁵ I reassess oxygenation and the radiograph before any attempt at extubation, and I explain to his parents what happened.

Pitfalls that cost points

Treating stridor as laryngospasm when the cause is a retained throat pack, blood clot or edema; I look and suction.
Extubating in a light plane "to be safe" after a tonsillectomy.

Rapid-fire

Q: Why does the capnograph go flat but the chest still move? A: The patient is making inspiratory efforts against a closed glottis; no gas moves, so there is no CO2 waveform and the chest and abdomen move paradoxically.

Q: Does IV lidocaine help? A: Lidocaine 1–1.5 mg/kg given about 2 minutes before extubation suppresses airway reflexes; I use it as prevention, not rescue.

Q: What makes children higher risk? A: A smaller functional residual capacity and higher oxygen consumption shorten the time to desaturation, and URIs, airway surgery and inhalational induction raise reflex sensitivity.

Q: How do you tell laryngospasm from bronchospasm? A: Laryngospasm gives stridor or silence with no gas exchange; bronchospasm gives wheeze, a prolonged expiratory upslope on the capnograph and high airway pressures with some ventilation possible.

Numbers to know

Item	Value
Propofol to deepen	0.5–0.8 mg/kg IV²
Succinylcholine, relaxing dose	0.1–0.5 mg/kg IV
Succinylcholine, intubating	1–2 mg/kg IV; 3–4 mg/kg IM, max 150 mg⁴
Atropine, child	0.02 mg/kg IV/IM³
Lidocaine for prevention	1–1.5 mg/kg IV before extubation
PEEP for negative-pressure edema	5–10 cmH2O

Sources

1.Laryngospasm · OpenAnesthesia (IARS), 2023 · openanesthesia.org
2.Pediatric laryngospasm (Hampson-Evans, Morgan, Farrar; consensus management algorithm) · Paediatric Anaesthesia, 2008 · mcgill.caPaediatr Anaesth 2008;18:303-7. Succinylcholine 1-2 mg/kg IV is the gold standard, some advise 0.1 mg/kg; propofol 0.5-0.8 mg/kg; atropine 0.02 mg/kg; IM succinylcholine 4 mg/kg.
3.Laryngospasm · Life in the Fast Lane · litfl.com
4.QUELICIN (succinylcholine chloride) injection prescribing information · FDA / DailyMed · dailymed.nlm.nih.govSection 2.4: IM up to 3-4 mg/kg, total IM dose not to exceed 150 mg, onset about 2-3 min.
5.Negative pressure pulmonary edema (Review) · Experimental and Therapeutic Medicine, 2023 · ebi.ac.ukFull text via Europe PMC (PMC10443067).

Facts on this page were checked against these sources on Oct 14, 2026. Guidelines change; confirm doses against current institutional protocols.