Laryngospasm
Respiratory
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.
- Succinylcholine 4 mg/kg IM (max 200 mg) in deltoid or quadriceps
- 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?
High
We are highly confident that the true effect lies close to that of the estimate of the effect. There is a wide range of studies included in the analyses with no major limitations, there is little variation between studies, and the summary estimate has a narrow confidence interval.
Moderate
We consider that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. There are only a few studies and some have limitations but not major flaws, there are some variations between studies, or the confidence interval of the summary estimate is wide.
Low
When the true effect may be substantially different from the estimate of the effect. The studies have major flaws, there is important variations between studies, of the confidence interval of the summary estimate is very wide.
Justification
Limited literature available including guidelines from the Difficult Airway Society and recent meta-analyses on adverse events during procedural sedation in the ED.
Related Information
Reference List
Relevant Resources
RESOURCE AUTHOR(S)
DISCLAIMER
The purpose of this document is to provide health care professionals with key facts and recommendations for the diagnosis and treatment of patients in the emergency department. This summary was produced by Emergency Care BC (formerly the BC Emergency Medicine Network) and uses the best available knowledge at the time of publication. However, healthcare professionals should continue to use their own judgment and take into consideration context, resources and other relevant factors. Emergency Care BC is not liable for any damages, claims, liabilities, costs or obligations arising from the use of this document including loss or damages arising from any claims made by a third party. Emergency Care BC also assumes no responsibility or liability for changes made to this document without its consent.
Last Updated Jul 03, 2020
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