Laryngeal mask airway

A laryngeal mask airway — also known as laryngeal mask— is a medical device that keeps a patient's airway open during anaesthesia or unconsciousness. It is a type of supraglottic airway.

A laryngeal mask is composed of an airway tube that connects to an elliptical mask with a cuff which is inserted through the patient's mouth, down the windpipe, and once deployed forms an airtight seal on top the glottis (unlike tracheal tubes which pass through the glottis) allowing a secure airway to be managed by a health care provider.

They are most commonly used by anaesthetists to channel oxygen or anaesthesia gas to a patient's lungs during surgery and in the pre-hospital setting (for instance by paramedics and emergency medical technicians) for unconscious patients.

The laryngeal mask was invented by British anaesthesiologist/anaesthetist Archibald Brain in the early 1980s and in December 1987 the first commercial laryngeal mask was made available in the United Kingdom. The laryngeal mask is still widely used today worldwide and a variety of specialised laryngeal masks exist.

A laryngeal mask has an airway tube that connects to an elliptical mask with a cuff. The cuff can either be of the inflating type (achieved after insertion using a syringe of air), or self-sealing. Once inserted correctly (and the cuff inflated where relevant) the mask conforms to the anatomy with the bowl of the mask facing the space between the vocal cords. After correct insertion, the tip of the laryngeal mask sits in the throat against the muscular valve that is located at the upper portion of the esophagus.

Dr. Archie Brain began studying the anatomy and physiology of the upper airway in relation to existing airways. Dr. Brain concluded that current techniques for connecting artificial airways to the patient were not ideal, reasoning that if the respiratory tree is seen as a tube ending at the glottis and the objective is to connect this tube to an artificial airway, the most logical solution was to create a direct end-to-end junction. Existing airway devices clearly failed to form this junction; the face-mask sealed against the face, and the endotracheal tube penetrated too far so that the junction was created within the trachea, instead of at its beginning. Dr Brain wrote in his diary in May 1981, "Better, use a loop fitting into the anatomical loop of space surrounding the larynx, with a projection downwards into the oesophagus, which could be hollow, to drain regurgitant fluid.“

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