Gender + recovery after general anesthesia combined with neuromuscular blockin

January 23, 2006

Anesth Analg. 2006 Jan;102(1):291-7.

Gender and recovery after general anesthesia combined with

neuromuscular blocking drugs.

Buchanan FF, Myles PS, K, Forbes A, Cicuttini F.

Department of Anesthesia and Pain Management, Alfred Hospital,

Melbourne, Australia.

Previous studies suggest that women recover faster from general

anesthesia than men, but it is unclear whether this is a result of a

gender effect or differences in the pattern of drug administration or

type of surgery. We performed a subset analysis comparing recovery

characteristics from general anesthesia combined with neuromuscular

blocking drugs of female and male patients, at risk of awareness,

enrolled in a large trial testing the effectiveness of bispectral

index (BIS) monitoring. We used multivariate statistical methods to

adjust for differences in baseline characteristics, duration and

extent of surgery, and anesthetic drug administration in 1079

patients (584 male, 495 female). Female patients had higher BIS

values than male patients despite similar amounts of anesthetic drug

administration (time-averaged mean [sd] BIS: male 44.6 [7.1] versus

female 46.4 [6.6]; P = 0.005). Time to eye opening after anesthesia

and time to eligibility to discharge from the postanesthesia care

unit were less in women than men (male 13.9 [13.2] min versus female

10.6 [11.6] min; P < 0.001; male 133 [209] min versus female 78 [106]

min; P < 0.001, respectively). These differences persisted after

multivariate adjustment (both P < or = 0.001). Gender has an

independent effect on recovery times in patients undergoing general

anesthesia combined with neuromuscular blocking drugs, with women

recovering faster than men. Higher BIS values during maintenance of

anesthesia in women, despite similar amounts of anesthetic drug

administration, suggests that women are less sensitive to the

hypnotic effect of anesthetic drugs than men and may help explain

faster recovery times in women.

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