Women have the same desflurane minimum alveolar concentration as men: a prospective study.

BACKGROUND Women generally report greater sensitivity to pain than do men, and healthy young women require 20% more anesthetic than healthy age-matched men to prevent movement in response to noxious electrical stimulation. In contrast, minimum alveolar concentration (MAC) for xenon is 26% less in elderly Japanese women than in elderly Japanese men. Whether anesthetic requirement is similar in men and women thus remains in dispute. The authors therefore tested the hypothesis that the desflurane concentration required to prevent movement in response to skin incision (MAC) differs between men and women. METHODS Using the Dixon "up and down" method, the authors determined MAC for desflurane in 15 female and 15 male patients (18-40 yr old) undergoing surgery. RESULTS MAC was 6.2 +/- 0.4% desflurane for women versus 6.0 +/- 0.3% for men (P = 0.31), a difference of only 3%. These data provide 90% power to detect a 9% difference between the groups. CONCLUSIONS The MAC of desflurane did not differ between young men and women undergoing surgery with a true surgical incision. Although pain sensitivity may differ in women versus men, MAC of desflurane does not.