Influences of gender on postoperative morphine consumption

Gender related differences on morphine consumption during postoperative period following abdominal surgeries.

Four hundred and fifty ASA I & II patients of either sex (male =231, female = 219), between the age group of 18-65 y undergoing elective intra abdominal surgeries under general anaesthesia were included for the study. Patients with preexisting pain either acute or chronic preoperatively were excluded from the study. Anaesthesia and analgesia protocol during surgery was standardized. Postoperatively, a loading dose was given to achieve the visual analogue scale (VAS) of ≤30 and subjects were connected to patient control analgesia (PCA) pump containing 0.4 mg/ml of morphine configured to deliver a bolus dose (1 mg) with a 5 min lock-out period. The total analgesic requirements along with VAS (visual analog scale) score were analysed between males and females in the first 24 h postoperatively. All demographic data and between group comparisons were analysed with student t-test. Within group comparisons were done by using one-way-ANOVA test and Tukey's Honestly significant Difference test.

During the first 24 h, males consumed significantly higher amount of morphine (34.35 ± 6.68 mg) when compared to females (26.78 ± 7.14 mg), p < 0.001.

We conclude that men require more morphine in the postoperative period than women.