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  • Dr Hector Thomson

Laryngospasm

Updated: Apr 8

Dr Hector Thomson Emergency Registrar

Peer review: Dr David McCreary


On a recent anaesthetic rotation during a paeds ENT list I heard a delightful description of laryngospasm. “Oh they are just a little squeaky… give them some PEEP it’ll be fine.” I immediately thought of the Toy Story 2 character, Wheezy, the adorable penguin who gets put on the shelf when his squeaker is broken! He tries squeaking for help but no one can hear him and the dust aggravates his condition!



It took me a fair few lists before I stopped fearing the squeak!


WHAT IS LARYNGOSPASM?

Laryngospasm is a potentially life-threatening closure of the true vocal cords resulting in partial or complete airway obstruction. This is a primitive protective airway reflux that aims to protect against aspiration but can cause life-threatening hypoxia.


ANATOMY REVISION

In laryngospasm, either the true cords alone or the false cords slam shut and close the glottis. Most laryngeal reflexes are produced by stimulation of the superior laryngeal nerve which provides sensory innervation to the supraglottic region. This is a branch of the vagus nerve. The muscles involved are the lateral cricoarytenoid and thyroarytenoids (the adductors) and the cricothyroid (the vocal cord tensors). The cricothyroid muscle is the only tensor of the vocal cords. Gentle pressure from a jaw thrust may overcome moderate laryngospasm.

Image: https://teachmeanatomy.info/neck/viscera/larynx/muscles/

The AIME Airway Course website has some amazing videos and images on airway anatomy. The vocal cords are white and triangular. Anteriorly sits the epligottis, laterally the aryepiglottic folds and posteriorly the cuneiform and corniculate tubercles and the interarytenoid notch.


Image: https://aimeairway.ca/announcement/62/excerpts-from-airway-physiology-and-anatomy-a-deep-dive-chapter-in-airway-management-in-emergencies-the-infinity-edition

Image: Paediatric Anaesthesia Digital Handbook

WHAT CAUSES IT?

Local causes:

  • Extubation: children with URTI symptoms (beware the snotty child)

  • Airway manipulation (especially when under light anaesthesia)