INDEX

    Laryngospasm

    Respiratory

    Last Updated Jul 03, 2020
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    Context

    • Potentially life-threatening sustained closure of the vocal cords, resulting in partial or complete loss of the airway.
    • Due to an exaggerated response from a primitive protective airway reflex.
    • Incidence during anesthesia:
      • 1% overall, 2% in children, 3% in infants.
      • 10% in children with reactive airways.
    • Incidence during ED procedural sedation:
      • 1% overall with propofol.
      • 0.3% in children with ketamine.

    Risk Factors

    • Insufficient depth of sedation / anesthesia.
    • Airway irritation
      • Mucous, blood, manipulation (laryngoscopy, suction catheter).
    • LMA (not definitive airway).
    • Ketamine.
    • Young age (children).
    • Airway hypersensitivity.
      • Asthma, recent URTI, smoking exposure (passive and active).
    • Obesity with Obstructive Sleep Apnea.
    • Gastroesophageal reflux.
    • Airway anomaly.

    Clinical Presentation

    • Not always clinically obvious (23% are not obvious).
    • Common signs:
      • Inspiratory stridor.
      • Increased respiratory effort.
      • Tracheal tug.
      • Paradoxical respiratory effort.
      • Oxygen desaturation +/- bradycardia.
      • Airway obstruction which does not respond to an OPA.

    Context

    • Check for blood or stomach contents in larynx.
    • Remove any triggering stimulation.
    • Place appropriately sized OPA to ensure patency of the supraglottic airway.
    • Apply CPAP with 100% oxygen:
      • Avoid vigorous attempts at ventilation (risk of diaphragmatic splinting).
      • May worsen soft-tissue compression of larynx if not accompanied by vigorous jaw thrust.
    • Vigorous jaw thrust:
      • Lifts the tongue off the pharyngeal wall.
      • May help lift the supraglottic tissues from the false vocal cords.
      • Majority of laryngospasm will resolve with above CPAP + jaw thrust.
    • Deepen anesthesia with propofol IV 0.5 mg/kg increments
      • Inhibits airway reflexes and relaxes tissues in the upper airway.
      • Advantages: Rapid onset (30-45 seconds), rapid clearance, and avoidance of side effects associated with succinylcholine.
    • Paralyze
      • Succinylcholine 0.1-0.2 mg/kg IV: Time for full paralysis is 30-45 s.
      • If no IV access:
        • Succinylcholine 4 mg/kg IM (max 200 mg) in deltoid or quadriceps
          • Time to break laryngospasm: 45 s–1 min.
        • Succinylcholine 2 mg/kg intralingual (i.e. IM injection into body of the tongue):
          • Tongue retains blood flow more than peripheral skeletal muscle in times of reduced perfusion.
          • Quicker onset than IM.
          • High incidence of arrhythmias (>50%), usually self-limiting.
          • Requires removal of tight-fitting mask to administer.
        • Succinylcholine 1 mg/kg IO:
          • Time of onset similar to IV.
          • Most reliable route in peri-arrest situation.
      •  Rocuronium 0.2 mg/kg IV: Lasts longer than succinylcholine.
    •  Limited evidence for:
      • Larson’s manoeuvre, described as bilateral digital pressure on the styloid process behind the posterior ramus of the mandible and anterior to mastoid process.
      • Gentle chest compressions, using half the force of CPR at 20-25 compressions/min. This is thought to force the glottis open by increasing intra-thoracic pressure, and stimulate shallow breaths.

    Complications

    • Desaturation: 61%.
    • Post-obstructive pulmonary edema: 3-4%.
    • Pulmonary aspiration: 3%.
    • Bradycardia: 6% overall, 23% in age <1 yr.
    • Cardiac arrest 0.5%.

    Ketamine-Related Laryngospasm

    • Incidence of laryngospasm in pediatric procedural sedation:
      • Ketofol > Ketamine > Propofol.
      • Ketamine IM > IV.
    • No significant difference in incidence of laryngospasm when premedicated with anticholinergics.
    • Low-dose ketamine for pain management not associated with laryngospasm.

    Quality Of Evidence?

    Justification

    Limited literature available including guidelines from the Difficult Airway Society and recent meta-analyses on adverse events during procedural sedation in the ED.

    Moderate

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