The use of muscle relaxants at the induction of anaesthesia of patients with a full stomach

Abstract

The use of a muscle relaxant after a rapid induction of anaesthesia will facilitate intubation and prevent vomiting when the patient is paralyzed. After paralysis, fluid may flow passively from the stomach and oesophagus if the patient be horizontal or tilted head-down, and will make rapid endotracheal intubation difficult, thus putting the patient in hazard from hypoxia. Tracheal aspiration is, however, unlikely. The passive movement of fluid is prevented by a foot-down tilt during induction, but, if any other factor cause fluid to reach the oropharynx in this position, tracheal aspiration is very likely, and has occurred in several instances. Possible factors are attempted vomiting before the onset of paralysis, abnormalities of the gastro-oesophageal junction, perhaps associated with respiratory trouble during induction, and changes in intragastric pressure during induction. The dangers of methods dependent on a muscle relaxant in the hands of inexperienced doctors are stressed, and the need to consider gastric decompression and to practice pre-oxygenation of the patient prior to anaesthesia are emphasized. It is concluded that insufficient evidence is available to favour one position more than another during induction. Cricoid pressure to occlude the oesophagus against the cervical veretebrae should be used, if the supine horizontal position be chosen. © 1963 John Sherratt and Son.