Intraoperative low-dose ketamine infusion for postoperative pain relief in laparoscopic surgeries – A randomised, double blind controlled clinical trial

Abstract

Abstract Background: Patients undergoing laparoscopic surgery often experience moderate-to-severe postoperative pain. The use of opioids for postoperative pain relief often results in respiratory depression and other adverse effects. Hence, we studied the effect of ketamine infusion administered at a low dose intraoperatively on postoperative pain relief. Materials and Methods: Fifty-two patients belonging to American Society of Anesthesia (ASA) I/ASA II, scheduled for laparoscopic surgery were randomized into two groups (n = 26). Group A received 0.2 mg/kg bolus of ketamine before the skin incision followed by an infusion of 0.1 mg/kg/h throughout the period of surgery. Group B received an equal volume of saline bolus and infusion. Postoperative pain was assessed (Numerical Rating Scale [NRS] scale) every 30 min till 6 h. The time taken for first rescue analgesia, the total amount of opioid used, and degree of sedation postoperatively were also compared. Pain scores between the groups were compared using the Chi-square test. Results: Pain scores (NRS scores) over various time intervals postoperatively were significantly reduced in the ketamine group (P < 0.001). The overall cumulative opioid consumption was significantly lower in the ketamine group compared to the placebo (69.29 ± 23.35 mg vs. 107.88 ± 35.21 mg, respectively, P = 0.008). There was also a significant difference in time to first rescue analgesia between the ketamine and placebo groups (2.60 ± 1.87 h vs. 0.43 ± 0.85 h, respectively, P = 0.001). Conclusion: Intraoperative low-dose ketamine infusion as an adjuvant significantly decreased postoperative pain with a reduced total dose of opioid consumption and a delayed time to first rescue analgesic.