evaluation of the postoperative analgesic efficacy of intraperitoneal ketamine compared with bupivacaine in laparoscopic cholecystectomy

background: this randomized controlled study was designed to compare the postoperative analgesic efficacy of intraperitoneal ketamine versus bupivacaine in patients undergoing laparoscopic cholecystectomy. methods: we randomly divided 60 patients undergoing elective laparoscopic cholecystectomy into two groups. the intervention group patients received intraperitoneal ketamine (0.5 mg/ kg) diluted in 30ml normal saline and the control group received intraperitoneal bupivacaine 30 ml 0.25% (75mg) at the end of the procedure, before removal of the trocars. the primary end point of this study was, time to tracheal extubation and the intensity of postoperative pain by using visual analogue scale (vas) score at 5-15min, 6, 12 and 24 h after surgery. the secondary outcome included time to the first request of analgesia in the postoperative period, total dose of analgesic used in first 24 h postoperative period and any postoperative complication. results: time to tracheal extubation was higher in ketamine group compared to bupivacaine group that caused prolongation of anesthetic duration in this group. during the first 6 h after surgery, the pain scores were significantly lower in patients receiving ketamine compared with bupivacaine group. pain scores in the subsequent time were low but were not different between the two groups. time to first request of analgesia was longer in ketamine group (21.43±0.50 min) compared to bupivacaine group (6.32±0.64 min) (p=0.001). total meperidine consumption was also lowest in ketamine group compared to bupivacaine group. conclusion: intraperitoneal instillation of 0.5mg/kg ketamine in elective laparoscopic cholecystectomy significantly reduces the postoperative pain and the analgesic requirement in the first 6 h after surgery as compared to bupivacaine but it increased extubation time.