Cricoid pressure: a review of the literature

Aspiration pneumonitis (Mendelson's syndrome) is universally accepted as a complication of general anaesthesia. According to Ellis et al (2007) death from aspiration was first described by Simpson in 1848, and it was not until 1946 that Mendelson identified acid aspiration in a significant number of obstetric patients undergoing facemask anaesthesia. The advent of techniques to secure the airway, through the use of airway adjuncts has gone some way to reduce the likely incidence of aspiration in today's perioperative arena. The positive outcome for patients is corroborated by Neilipovitz & Crosby (2007) who report aspiration as a rare complication with an overall incidence of 1:2,000-3,000. As Ewart (2007) highlights, Mendelson's syndrome is due to pharmacological effects at a molecular level which occur in the airway tissues and are caused by the use of induction and neuromuscular blocking agents. The resultant loss of consciousness and consequent diminished protective airway reflexes ultimately places the patient at risk until their airway is secured. Preventative measures to protect the lung from contamination with gastric contents, for example preoperative fasting, are therefore instigated prior to securing the airway.