The procedure is an emergency cricothyroidotomy. The incision is made over the cricothyroid membrane, the palpable gap between the lower border of the thyroid cartilage and the cricoid cartilage. This site is chosen in the crash airway because it is superficial, crossed by no major vessel or the thyroid isthmus, and can be opened with scalpel, bougie and a size 6.0 tube within a minute. It is indicated in the cannot-intubate, cannot-oxygenate situation from maxillofacial trauma, laryngeal oedema or foreign body, and is avoided in children under about 12 years and in suspected laryngeal fracture.

Elective and emergency tracheostomy are both performed lower, through the second to fourth tracheal rings, needing division or retraction of the thyroid isthmus and taking far longer. Percutaneous tracheostomy is a bedside guidewire and serial dilator (Ciaglia) technique over the tracheal rings, done in ventilated ICU patients, not as a rescue.

Key point: Cricothyroidotomy is the fastest but only a temporary surgical airway - convert to formal tracheostomy within about 72 hours to avoid subglottic stenosis.