The action of inhalation anesthetics upon the lower oesophageal sphincter.

The lower oesophageal sphincter plays an important role as a gastro-oesophageal blocker. Its proper function as a reflux barrier for the prevention of regurgitation and aspiration during anesthesia is very important. Therefore the effect of inhalation anesthetics upon the lower oesophageal sphincter is of great interest. In 10 healthy volunteers we studied the action of various inhalation anesthetics upon the lower oesophageal sphincter, the distal oesophagus and the stomach. The inhalation of nitrous oxide-oxygen alone or in combination with 2 Vol. % halothane or enflurane resulted in a highly significant pressure drop (p < 0.001) at the lower oesophageal sphincter. All three anesthetics (nitrous oxide-oxygen, nitrous oxide-oxygen-halothane and nitrous oxide-oxygen-enflurane) caused a pressure rise at the distal oesophagus and a pressure decrease at the stomach.