Pressure applied to the cricoid cartilage to prevent gastric contents from leaking into the pharynx during tracheal intubation by extrinsic obstruction of the oesophagus.
In a series of cadaver experiments Sellick found that when the stomach was filled with water and Cricoid Pressure applied a steep Trendelenburg tilt did not cause regurgitation of fluid into the pharynx.
- B. A. Sellick:
Cricoid pressure to control regurgitation of stomach contents during induction of anaesthesia: preliminary communication.
The Lancet. 1961, 2: 404-406. "When the contents of the stomach or oesophagus gain access to the air-passages during anaesthesia, the consequences are disastrous. In spite of modern anaesthetic techniques or sometimes regrettably because of them, regurgitation is still a considerable hazard during induction of anaesthesia, particularly for operative obstetrics and emergency general surgery." "Cricoid pressure must be exerted by an assistant. Before induction, the cricoid is palpated and lightly held between the thumb and second finger; as anaesthesia begins, pressure is exerted on the cricoid cartilage mainly by the index finger. Even a conscious patient can tolerate moderate pressure without discomfort but as soon as consciousness is lost, firm pressure can be applied without obstruction of the patient's airway. Pressure is maintained until intubation and inflation of the cuff of the endotracheal tube is complete."