Effect of Patient Sex on General Anaesthesia and Recovery
Effect of Patient Sex on General Anaesthesia and Recovery
Background. Numerous studies have shown that women emerge faster from general anaesthesia than men, and differ in their postoperative recovery profile. The extent and underlying mechanisms for these sex-related differences in general anaesthesia are unclear.
Methods. In a multicentre, prospective, matched cohort study, 500 ASA physical status I or II patients of either sex undergoing general anaesthesia for elective surgery were recruited. All subjects received a general anaesthetic through inhalation. Anaesthetic drugs and doses used, bispectral index (BIS) scores, recovery times, pain scores, and 40-item quality of recovery (QoR-40) scores for 3 days after general anaesthesia were recorded.
Results. Women had higher BIS scores at similar concentrations of anaesthesia (P<0.05). Time to eye-opening (P<0.01) and time to obeying commands (P<0.01) were shorter in women. Duration of recovery room stay was longer in women, who also had higher pain scores and need for treatment of nausea and vomiting (all P<0.001). QoR-40 scores for the first 3 days after general anaesthesia were lower in women (P<0.001). Plasma progesterone concentrations in women negatively correlated with the time to eye-opening (ρ=−0.53, P=0.01).
Conclusions. Patient sex is an independent factor influencing the response to anaesthesia and recovery after surgery. Women emerged faster from general anaesthesia but their overall quality of recovery was poorer. Female sex hormones, particularly progesterone, might be involved, with premenopausal women having faster recovery time but poor overall recovery.
A growing body of evidence suggests that patient sex is an independent factor influencing the response to general anaesthesia. Women appear to be less sensitive to hypnotic drugs as assessed by doses required to achieve similar hypnotic depth and faster recovery times after the cessation of anaesthetic drug delivery. An apparent increased risk of awareness in women could in part be owing to this reduced susceptibility to anaesthetic drugs. In addition, women are at greater risk of other adverse outcomes postoperatively.
Sex hormones are neurosteroids and, like pregnanolone, have anaesthetic properties. Increased production of progesterone during the luteal phase of the menstrual cycle and pregnancy can decrease anaesthetic drug requirements. It remains unclear if sex-related reductions in sensitivity to general anaesthesia are primarily because of pharmacokinetic (faster clearance) or pharmacodynamic (less response at equal effect site concentrations) mechanisms. Some studies, however, have been unable to identify sex-specific differences in anaesthetic drug requirements.
Most previous studies were not specifically designed to investigate sex-related differences in general anaesthesia, instead relying upon post hoc analyses of the existing data. In view of the incomplete and contradictory nature of previous studies, we set out to examine the effect of patient sex on requirements and response to general anaesthesia, and recovery from anaesthesia, in a matched cohort study in adults undergoing general anaesthesia for elective surgery.
Abstract and Introduction
Abstract
Background. Numerous studies have shown that women emerge faster from general anaesthesia than men, and differ in their postoperative recovery profile. The extent and underlying mechanisms for these sex-related differences in general anaesthesia are unclear.
Methods. In a multicentre, prospective, matched cohort study, 500 ASA physical status I or II patients of either sex undergoing general anaesthesia for elective surgery were recruited. All subjects received a general anaesthetic through inhalation. Anaesthetic drugs and doses used, bispectral index (BIS) scores, recovery times, pain scores, and 40-item quality of recovery (QoR-40) scores for 3 days after general anaesthesia were recorded.
Results. Women had higher BIS scores at similar concentrations of anaesthesia (P<0.05). Time to eye-opening (P<0.01) and time to obeying commands (P<0.01) were shorter in women. Duration of recovery room stay was longer in women, who also had higher pain scores and need for treatment of nausea and vomiting (all P<0.001). QoR-40 scores for the first 3 days after general anaesthesia were lower in women (P<0.001). Plasma progesterone concentrations in women negatively correlated with the time to eye-opening (ρ=−0.53, P=0.01).
Conclusions. Patient sex is an independent factor influencing the response to anaesthesia and recovery after surgery. Women emerged faster from general anaesthesia but their overall quality of recovery was poorer. Female sex hormones, particularly progesterone, might be involved, with premenopausal women having faster recovery time but poor overall recovery.
Introduction
A growing body of evidence suggests that patient sex is an independent factor influencing the response to general anaesthesia. Women appear to be less sensitive to hypnotic drugs as assessed by doses required to achieve similar hypnotic depth and faster recovery times after the cessation of anaesthetic drug delivery. An apparent increased risk of awareness in women could in part be owing to this reduced susceptibility to anaesthetic drugs. In addition, women are at greater risk of other adverse outcomes postoperatively.
Sex hormones are neurosteroids and, like pregnanolone, have anaesthetic properties. Increased production of progesterone during the luteal phase of the menstrual cycle and pregnancy can decrease anaesthetic drug requirements. It remains unclear if sex-related reductions in sensitivity to general anaesthesia are primarily because of pharmacokinetic (faster clearance) or pharmacodynamic (less response at equal effect site concentrations) mechanisms. Some studies, however, have been unable to identify sex-specific differences in anaesthetic drug requirements.
Most previous studies were not specifically designed to investigate sex-related differences in general anaesthesia, instead relying upon post hoc analyses of the existing data. In view of the incomplete and contradictory nature of previous studies, we set out to examine the effect of patient sex on requirements and response to general anaesthesia, and recovery from anaesthesia, in a matched cohort study in adults undergoing general anaesthesia for elective surgery.
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