Comparative Effects of Buprenorphine and Morphine as Adjuvants to Bupivacaine Spinal Anaesthesia in Patients Undergoing Infra-Umbilical Surgeries – A Prospective Study

Abstract

Background: Adding adjuvants to local anaesthetics for spinal anaesthesia extends analgesic duration. Intrathecal Buprenorphine and Morphine have been shown to prolong analgesia. Hence, we aimed to compare the analgesic efficacy of intrathecal buprenorphine and morphine with hyperbaric bupivacaine.

Methods: This study was done on 60 patients. The primary objective was to calculate the time required for first rescue analgesia. The secondary objective was to compare the time to reach maximum sensory and motor block, side effects and hemodynamic changes. Group B received 2.8ml of 0.5% hyperbaric bupivacaine with Buprenorphine 0.2 ml (60 mcg). Group M received 2.8ml of 0.5% hyperbaric bupivacaine with Morphine 0.1 ml (100mcg) and 0.1 ml normal saline, amounting to 3ml. Statistical analysis was done with unpaired t test.

Results: A total of 57 patients were analyzed. Both the groups were similar in demographic profile. Time for first rescue analgesic (Group M 1071.42 ± 207.01 min vs Group B 473.10 ± 123.66 min, P < 0.001) was significantly delayed in Group M. Time to achieve maximum sensory block (Group M 13.85 ± 4.24 min vs Group B 17.31 ± 3.67 min, P = 0.002) was shorter in Group M. Time to achieve maximum motor block (Group M 11.21 ± 3.41 min vs Group B 12.68 ± 3.12, P = 0.095) was similar in both the groups. Also, no hemodynamic changes and side effects were noted in both the groups.

Conclusion: Intrathecal morphine, when compared with intrathecal buprenorphine provides prolonged postoperative analgesia without any undesirable side effects.