The effect of 50% nitrous oxide in oxygen on lower oesophageal sphincter tone.

The effect of 50% nitrous oxide on the lower oesophageal sphincter was studied in eight healthy volunteers. No effect on the sphincter tone was noted in these subjects. The importance of this finding is discussed in relation to the depressant effects of nitrous oxide and other anaesthetic or sedative drugs on the reflex protective mechanisms safeguarding the respiratory tract and lungs from aspiration of acid gastric content and other foreign matter.