Closure of the glottic opening by constriction of the intrinsic laryngeal muscles is a protective airway reflex to prevent against pulmonary aspiration.3 It is normally triggered by a peri-glottic stimulus mediated via the vagus nerve. Sensory fibres from laryngeal mechanical, chemical, and thermal receptors ascend via the vagus nerve, via the internal branch of the superior laryngeal nerve. The highest receptor density exists posteriorly at the true vocal cords, where foreign material is most likely to spill into the airway. The motor response is via the three main intrinsic laryngeal muscles, the lateral cricoaretenoids, thyroaretenoids (the glottic adductors), and cricoaretenoids (the vocal cord tensors). They are all supplied by the vagus nerve via the recurrent laryngeal nerve (the external branch of the superior laryngeal nerve supplies only the cricothyroid muscle). Glottic closure occurs by either true vocal cord adduction alone or in conjunction with adduction of the false vocal cords. Additionally, the supraglottic soft tissues are thought to impact into the glottis as they are pulled down by an increasing translaryngeal pressure gradient during obstructed inspiratory effort. The soft tissue compression of the larynx, as the intralaryngeal pressure becomes subatmospheric, can be improved by the application of continuous positive airway pressure