Anxiolytic effects of low dosage nitrous oxide-oxygen mixtures administered continuously in apprehensive subjects

We observed the effect of low doses of nitrous oxide on the cardiovascular and respiratory systems, the cortisol output in blood and saliva, and the degree of sedation and analgesia of 20 volunteers. A psychologic screening inventory was also performed. We found nitrous oxide, at low dosage, to be primarily an anxiolytic and not an analgesic or amnesic agent. The nasally inhaled concentrations necessary to induce an anxiolytic effect varied from subject to subject, ranging from 30% to 65% and averaging 35% to 40%. This finding justifies the use of the gas to relieve anxiety instead of nonvolatile parenterally administered psychosedatives and narcotics. Nitrous oxide is preferable because its action is established within several minutes, it is rapidly eliminated at the conclusion of a procedure, and the sensorium is clear after five or six minutes. The gas is simply and safely administered with fail-safe apparatus designed specifically for this purpose. The technic is admirably suited for use in ambulatory care units where minor surgical or dental procedures are performed.