This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (9) Citing Articles via Google Scholar Google Scholar Articles by Janiszewski, D. J. Articles by Zacny, J. P. Search for Related Content PubMed PubMed Citation Articles by Janiszewski, D. J. Articles by Zacny, J. P.

---

GENERAL ARTICLES

The Effects of Subanesthetic Concentrations of Sevoflurane and Nitrous Oxide, Alone and in Combination, on Analgesia, Mood, and Psychomotor Performance in Healthy Volunteers

Department of Anesthesia and Critical Care, University of Chicago, Chicago, Illinois

Address correspondence and reprint requests to James P. Zacny, PhD, DACC MC 4028, University of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637. Address e-mail to zacn{at}midway.uchicago.edu

We studied the effects of subanesthetic concentrations of sevoflurane and nitrous oxide, alone and in combination, on analgesia, mood, and psychomotor performance in human volunteers. We hypothesized that nitrous oxide and sevoflurane would produce both opposing and potentiating effects within the same study. Over the course of three sessions, 20 subjects inhaled 0%, 0.2%, or 0.4% end-tidal sevoflurane for a 68-min period that was divided into four 17-min blocks. During either the second or fourth block, 30% end-tidal nitrous oxide was added to the concentration of sevoflurane being inhaled. Pain response, psychomotor performance, and mood were evaluated during the second and fourth blocks. Pain ratings were higher when sevoflurane and nitrous oxide were administered together than when nitrous oxide was administered alone, which indicates that sevoflurane attenuated the analgesic effects of nitrous oxide. Sevoflurane increased self-reported ratings of sleepiness, and the addition of nitrous oxide decreased these ratings. Nitrous oxide potentiated psychomotor impairment that was induced by sevoflurane. The combination of sevoflurane and nitrous oxide produced both opposing and potentiating effects within the same study. The results suggest that nitrous oxide and sevoflurane may act through different neurochemical mechanisms on some end points, such as analgesia and sleepiness.

Implications: Healthy volunteers inhaled subanesthetic concentrations of sevoflurane and nitrous oxide. Sevoflurane made nitrous oxide less effective as an analgesic, and nitrous oxide made sevoflurane less effective as a sedative. The two drugs may work at cross purposes on different end points of anesthesia.

This article has been cited by other articles:

				S. T. Yeo, A. Holdcroft, S. M. Yentis, A. Stewart, and P. Bassett Analgesia with sevoflurane during labour: II. Sevoflurane compared with Entonox for labour analgesia Br. J. Anaesth., January 1, 2007; 98(1): 110 - 115. [Abstract] [Full Text] [PDF]