Gastric regurgitation during general anaesthesia in different positions with the laryngeal mask airway.

Ninety patients, divided into three groups of 30, were investigated to determine the incidence of gastric regurgitation during general anaesthesia administered via the laryngeal mask airway in the supine, Trendelenburg and lithotomy positions. Fifteen minutes before induction of anaesthesia each patient swallowed a 75 mg methylene blue capsule. At the end of surgery, the LMA and the oropharynx were inspected for bluish discoloration which was considered to be a sign of gastric regurgitation. No blue dye was detected in the supine group but it was observed in one patient in each of the other two groups.