Laryngospasm

Who is at risk - Infants and young children top the list. Active asthma, an upper respiratory infection within the last 6 weeks, and second-hand smoke exposure each carry up to a 10-fold increase. Obesity at or above the 85th BMI percentile with sleep-disordered breathing, reflux, and OSA add to it, as do airway anomalies: subglottic stenosis, laryngeal papilloma, cleft palate, vocal cord paralysis, laryngomalacia, tracheal stenosis.

High-risk procedures - Shared-airway cases lead, with tonsillectomy and adenoidectomy running over 20% incidence, then bronchoscopy. Esophageal endoscopy stimulates distal esophageal afferents; thyroid surgery does it through superior laryngeal nerve injury or hypocalcemia. Appendectomy, hypospadias repair, skin grafting, and cervical dilatation also show up.

Prevention - Limit laryngoscopy attempts; adverse airway events climb with each one. Magnesium 15 to 30 mg/kg before induction, IV lidocaine 1 to 2 mg/kg within 5 minutes of extubation, and propofol 0.5 mg/kg 60 seconds before extubation each lower the incidence.

Awake versus deep extubation - No clear advantage either way in the pediatric literature, so choose by patient and case rather than by rule.

First moves - 100% oxygen with CPAP through a tight-fitting mask, remove the offending stimulus, and a vigorous jaw thrust. The thrust lifts the epiglottis off the glottic opening, rocks the larynx forward, and hurts enough to stimulate the patient. Don't bag hard — that just insufflates the stomach.

Larson maneuver - Firm inward pressure in the laryngospasm notch, slightly cephalad to the earlobe between the mastoid process behind and the mandibular condyle in front, done together with a jaw thrust. Use it early, but don't wait for desaturation before reaching for drugs.

Drug escalation - Propofol 0.5 mg/kg IV or midazolam 0.03 mg/kg IV first; both blunt upper airway reflexes and propofol works in 30 to 45 seconds. If the spasm holds, succinylcholine 1 to 2 mg/kg IV with atropine 0.02 mg/kg to prevent the bradycardia.

No IV access - Succinylcholine 4 mg/kg IM is the most reliable way to break it. Airway tissue relaxes within about a minute even though maximal twitch depression takes 3 to 4 minutes, and at that dose the block can last upward of 20 minutes.

When succinylcholine is out - Burns, muscular dystrophies, and cholinesterase deficiency push you to propofol as the pharmacologic breaker.

Volatile choice - Airway irritability ranks desflurane > isoflurane > halothane = sevoflurane, so desflurane is a poor pick in an already twitchy airway.

After the event - Watch for negative-pressure pulmonary edema and aspiration; both follow prolonged obstructed inspiratory effort. Hypoxemia, bradycardia, and arrest are the endpoints if it isn't broken.

Laryngospasm is an exaggeration of the protective glottic closure reflex — sustained closure of the true and false vocal cords plus redundant supraglottic tissue, partially or completely obstructing airflow to the trachea. Sensory input runs through the internal branch of the superior laryngeal nerve off the vagus; the motor response goes through the intrinsic laryngeal muscles by way of the recurrent laryngeal nerve. Abnormal excitation of that pathway happens most often when a patient is stimulated in a light plane (stage 2), which is why induction, airway instrumentation, and emergence are the dangerous moments. Incidence in children under 15 is about 0.53%. Hypoxia often breaks the spasm on its own; unrelieved, it leads to pulmonary edema, aspiration, bradycardia, dysrhythmias, and cardiac arrest.