Effect of Low-Dose Ketamine Infusion on Quality and Duration of Post-Operative Pain in Patients undergoing Laparoscopic Cholecystectomy under General Anesthesia

Background: Because of its analgesic properties and cardiovascular stability, ketamine has been used extensively in anesthesia practice. In a range of surgical procedures, low-dose ketamine infusions (<0.3 mg/kg/hr) have demonstrated effectiveness in lowering pain scores. Objective: To determine the effect of low-dose ketamine infusion on quality and duration of post-operative pain in patients undergoing laparoscopic in a tertiary care hospital. Materials and Methods: This Double-blinded randomized control trial was performed in Department of Anesthesia at Fazaia Ruth Pfau Medical College, Pakistan Air Force Hospital, Base Faisal, Karachi from 1st October 2024 to 30th April 2025. Group A received ketamine at 0.2mg/kg bolus intravenously followed by ketamine infusion at rate of 0.2mg/kg/hr. Whereas control group was served as Group B which received normal saline at an equivalent infusion rate. Pain was assessed using Numeric Rating Scale. Result: A total of 58 patients per group were studied. Mean score was significantly lower in ketamine group at 0 hour (1.6±0.9 versus 2.7±1.2, p<0.001) and at 2 hours than control group (2.3±0.9 versus 4.8±1.2, p<0.001). Mean pain score at 4 hours (p=0.168), 6 hours (p=0.362), 12 hours (p=0.151) and 24 hours (p=0.272) was not significantly different. Time to first rescue analgesia was significantly longer in group A than group B (4.8 ± 1.7 versus 1.5 ± 0.8, p<0.001) whereas analgesic consumption was higher in group B than group A (2.5 ± 1.1 versus 1.6 ± 0.8, p<0.001). Conclusion: The administration of low-dose ketamine infusion intraoperatively was effective in reducing post-operative pain during the early post-operative period which is also evident by lower number of analgesics requirement and a longer time to first rescue analgesia in ketamine than control group.