Comparative study between doses of intrathecal morphine for analgesia after caesarean

Abstract

Background and objectives: Analgesia after caesarean section is important because postpartum women with pain have difficulty in mobility, which undermines breastfeeding. Intrathecal morphine provides adequate and prolonged analgesia after cesarean. The aim of this study was to compare the quality of analgesia provided by two doses of intrathecal morphine and its side effects in patients undergoing cesarean section.

Method: The study included 123 pregnant women with gestational age over 38 weeks and scheduled for cesarean section. The women were randomly allocated into two groups to receive either 50 or 100 μg of intrathecal morphine (Group 50/Group 100). All patients were intrathecally anesthetized with 12 mg of 0.5% hyperbaric bupivacaine. Patients were assessed between the 9(th) and 11(th) hour and the 22(nd) and 24(th) hour after blockade for quality of analgesia, analgesic consumption, side effects, and main cause of discomfort in the first 24 hours after surgery.

Results: There was similarity between groups regarding anthropometric data and obstetric history. There was no statistical difference in pain intensity between groups. In both groups, pain was more intense in the first 12 hours after anesthesia (p < 0.001). Tramadol hydrochloride consumption and time to first dose were similar in both groups. Pruritus was the most common side effect, with statistically higher incidence in Group 100 (p = 0.026).

Conclusions: Intrathecal morphine 50 μg provides the same quality of analgesia as 100 μg, with a lower incidence of side effects.

Keywords: Analgesia; Caesarean section; Intrathecal; Morphine; Side effects; Visual analogue scale.

Copyright © 2013 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.