The effects of subanaesthetic concentrations of xenon in volunteers.

Xenon at subanaesthetic concentrations produced sedation in healthy male volunteers, with the concentration needed ranging from 27% to 45% (median 35%). Respiratory rate decreased markedly during xenon sedation, but no airway irritability occurred. Eight of ten subjects found xenon sedation pleasant and preferable to nitrous oxide, and one subject required anti-emetic treatment with nitrous oxide compared to none with xenon. The Critical Flicker Fusion test and electroencephalogram parameters did not reliably predict sedation. Xenon was well tolerated with no adverse physiological effects, though subjectively dissimilar to nitrous oxide.

Study at a glance

Abstract

This study reports the subjective, psychomotor and physiological properties of subanaesthetic concentrations of xenon. Ten healthy male volunteers received either xenon or nitrous oxide in a randomised crossover study design. The subjects breathed either xenon (Xe) or nitrous oxide (N2O) from a closed circuit breathing system, according to a randomised, double-blind protocol. The concentration of xenon required to produce sedation, ranged between 27 and 45% (median 35%). All subjects completed the xenon protocol. Subjects were tested using the Critical Flicker Fusion test and derived electroencephalogram parameters, however, neither test was found to reliably predict sedation. The respiratory rate decreased markedly during sedation with xenon. The subjects did not experience any airway irritability (coughing, breath-holding or laryngospasm) during administration of either gas. One subject required anti-emetic treatment in the N2O group compared to none in the Xe group. Eight subjects reported that they found sedation with xenon pleasant and preferable to nitrous oxide. Xenon sedation was well tolerated and was not associated with any adverse physiological effects, however, it was reported to be subjectively dissimilar to nitrous oxide.