Role of Low Dose Intravenous Ketamine for Postoperative Pain Relief Following Laparoscopic Cholecystectomy

Abstract

Background: Laparoscopic cholecystectomy provides faster recovery but postoperative pain still remains a persistent challenge. Many patients experience visceral, somatic, or referred pain despite multimodal analgesic strategies, which are often limited by side effects and inconsistent efficacy. In this context, low-dose intravenous ketamine has emerged as a promising preemptive option, with the potential to reduce pain intensity, delay analgesic demand, and enhance overall recovery. The main objective of this study was to evaluate effectiveness of low dose intravenous ketamine for postoperative pain relief in laparoscopic cholecystectomy.
Materials and methods: This quasi-experimental study was carried out over one year at the Department of Anaesthesia, Analgesia and Intensive Care Medicine of Bangladesh Medical University, Dhaka, following ethical approval. A total of 90 patients aged 18–60 years undergoing laparoscopic cholecystectomy under general anesthesia were enrolled. Participants were divided into two groups. Group K who received low dose intravenous ketamine & Group NS received normal saline as placebo. Postoperative pain was assessed using the Visual Analogue Scale (VAS) at 0, 1, 2, 6, 12, and 24 hours. Rescue analgesia with IV
pethidine (1 mg/kg) was given for VAS ³4. Outcomes included pain scores, time to first analgesic, total opioid requirement, haemodynamic parameters, and patient satisfaction.
Result: Postoperative pain intensity was significantly lower in the Group K at recovery (1.3±1.3 vs.1.8±1.4,p<0.05), at 1 hour (1.8±1.3 vs.2.5±1.7,p<0.05), and at 2 hours (2.0±1.4 vs.5.1±1.6,p<0.05), but differences diminished at later time points. Heart rate remained similar at most intervals, though significant differences were noted intraoperatively at 90 minutes (73.7±4.5 vs.68.7 ±4.3,p<0.05) and postoperatively at 1 hour (80.9±8.4 vs.90.3±11.6,p<0.05). Systolic blood pressure was stable pre and intraoperatively, but maintained significantly lower values at 1 hour (113.2±10.5vs.129.0±10.0,p<0.05) and at 2 hours(111.9±10.6 vs.130.7±12.6,p<0.05) postoperatively in Group K. Diastolic and mean arterial pressures were similar both preoperatively and intraoperatively, yet Group K again showed significantly lower MAP values at 1 hour(79.4±9.0vs.2.7±11.7,p<0.05) and at 2 hour s(79.6±9.3 vs. 94.0±10.4,p<0.05) postoperatively. Adverse effects did not differ significantly between groups. Group K showed, significantly prolonged the time to first analgesic demand, reduced total opioid consumption, and extended analgesia duration, although patient satisfaction scores were nearly identical across groups.
Conclusion: Low dose intravenous ketamine, reduces the postoperative pain scores, delayed first analgesic demand and reduced opioid consumption.