Randomized double blind trial of intraperitoneal instillation of bupivacaine and morphine for pain relief after laparoscopic gynecological surgeries

BACKGROUND: Intraperitoneal injection of anesthetic has been proposed to minimize postoperative pain after laparoscopic surgery. So a randomized, placebo-controlled study was conducted to compare the effectiveness of intraperitoneal bupivacaine with or without morphine for postoperative analgesia after laparoscopic gynecological surgeries. METHODS: A total of 90 ASA I and II female patients scheduled for laparoscopic gynecological procedures were enrolled in the randomized double blind prospective study. The drug was injected intraperitoneally before the removal of trocar at the end of surgery. In group BM (n=30): 0.25% bupivacaine 30 ml + 2 mg morphine, in group BO (n=30) 30 ml 0.25% bupivacaine and in group C (n=30) 30 ml of saline was injected intraperitoneally. Postoperative quality of analgesia was assessed by VAS (0-100), for 24 hours and when VAS >40, rescue analgesic was administered. Total dose of rescue analgesia and side effects were noted. RESULTS: Intraperitoneal instillation of bupivacaine and morphine significantly reduces immediate postoperative pain (VAS: 23.33±6.04 vs. 45.5±8.57). It also reduces pain at 4 hours after surgery in the BM group (VAS 24±12.13 vs. 41.17±7.27 in the BO group). The time of administration of first rescue analgesic was significantly higher in the BM group (6.15 hours) compared to the BO group (4.51 hours). The total dosage of rescue analgesic was more in the BO and C groups compared to the BM group. CONCLUSION: Addition of morphine to local anesthetic significantly prolonged the time to first rescue analgesic requirement and the total consumption of rescue analgesic in 24 hours without any significant increase in adverse events.