A comparative study of the analgesic efficacy of intraperitoneal instillation of diluted bupivacaine versus non-diluted bupivacaine after laparoscopic cholecystectomy, a prospective single-blinded controlled randomized study

Abstract

ABSTRACT Intraperitoneal (IP) bupivacaine instillation for postoperative analgesia after laparoscopic cholecystectomy (LC) has been reported in many studies as either diluted or non-diluted, with conflicting results and no standard recommendations. Objective Our study aims to compare the analgesic efficacy of intraperitoneal instillation of diluted versus non-diluted bupivacaine after laparoscopic cholecystectomy. Methods In this prospective, single-blinded, controlled and randomized study, we included 50 patients undergoing LC. They were randomly divided into two groups, with 25 patients each. At the end of surgery, the first group received intraperitoneal 20 ml bupivacaine 0.5% (100 mg), added to 480 ml normal saline, diluted bupivacaine group (DBG) and the second group received intraperitoneal 20 ml bupivacaine 0.5% (100 mg); non-diluted bupivacaine group (NBG). Pain was assessed and recorded using the visual analog scale (VAS) for 24 h. Time to the first analgesic request, total analgesic consumption in 24 h, incidence of negative effects after LC, such as nausea, vomiting and shoulder pain, any side effects due to local anesthetic used as hypotension, bradycardia or respiratory depression and hemodynamic parameters were also recorded. Results Postoperative VAS values were significantly lower in DBG than NBG in the 1st 24 h (P value ≤ 0.003). The duration of analgesia (the 1st time analgesic request) was significantly longer in DBG (20.16 ± 3.52 h) than that in NBG (6.19 ± 2.93 h) (P value = 0.0001). Also, the total amount of postoperative analgesic consumption (tramadol) was less in DBG (7.2 ± 19.9 mg) than NBG (63 ± 31.16 mg) (P value = 0.0001). In relation to negative effects after LC, side effects due to analgesic drugs and hemodynamic parameters, the results were comparable in both groups. Conclusion Intraperitoneal instillation of diluted bupivacaine at the end of laparoscopic cholecystectomy decreases postoperative pain, delays request for rescue analgesia and reduces the amount of analgesics in the 1st 24 h postoperatively, more than non-diluted bupivacaine, with comparable results in incidence-negative effects after LC, side effects due to analgesic drugs and comparable hemodynamic parameters.