Gender differences in propofol requirements during total intravenous anesthesia administered by closed-loop anesthesia delivery system: an observational study.

BACKGROUND

Propofol consumption during total intravenous anesthesia (TIVA) is influenced by patient's gender and females consume greater amount than males. As gender difference on propofol consumption during TIVA has only been assessed with manually titrated or target-controlled infusion, its validation with automated delivery systems, is desirable. This study evaluated effects of gender differences on propofol consumption during automated propofol TIVA administered by closed-loop anesthesia delivery system (CLADS).

METHODS

The enrolled patients (N.=80) were allocated to two groups based on gender- males and females, and all received automated propofol TIVA by CLADS. Cumulative intraoperative propofol consumption (primary outcome variable), anesthesia depth consistency, anesthesia delivery system performance, intraoperative hemodynamics (heart rate, mean blood pressure), recovery from anesthesia (time-to-eye-opening, time-to-tracheal extubation), and postoperative sedation (secondary outcome variables); were analyzed.

RESULTS

While no difference was found for propofol consumption during induction (males: 1.5±0.5 mg/kg versus females: 1.4±0.4 mg/kg, P=0.628) and maintenance (males: 4.9±1.3 mg/kg/h versus females: 4.9±0.8 mg/kg/h, P=0.457) based on total body weight, when calculated by lean body weight; females exhibited significantly greater propofol consumption for induction (males: 1.9±0.6 mg/kg versus females: 2.2±0.5 mg/kg, P<0.001) and maintenance (males: 6.4±1.5 mg/kg/h versus females: 7.8±1.3 mg/kg/h, P<0.001). Time to eye-opening (males: 7.2 [5.2, 9.3] minutes versus females: 4.6 [3.1, 6.7] minutes, P<0.001) and the time to tracheal-extubation (males: 8.1 [6.4, 10.5] minutes versus females: 6.4 [4.5, 9.1] minutes, P=0.010) were significantly lower in females.

CONCLUSIONS

While females consumed greater amount of propofol for induction and maintenance of propofol TIVA, they exhibited faster recovery than males.