Postoperative analgesia in laparoscopic surgeries with small dose of preemptive ketamine: A comparative study of three small doses

Preemptive N-methyl-D-aspartate (NMDA) receptor antagonist ketamine inhibits central sensitization in response to peripheral nociception. The purpose of our study was to compare efficacy of three small doses of ketamine for improving postoperative analgesia after laparoscopic surgeries. Materials and Methods: A total of 120 patients of American Society of Anesthesiologists physical status I–II undergoing laparoscopic surgeries were randomly allocated into four groups. Groups 1, 2, and 3 received intravenous ketamine in dose of 1, 0.75, and 0.5 mg/kg, respectively, and control Group 4 received isotonic saline 30 min before incision. Variations in heart rate and mean arterial pressure were noted, and response to pain at rest and at deep breathing was studied over 24 h. Fentanyl 0.5 μg/kg was used for rescue analgesia.Results: Visual analog scale score was significantly low in Groups 1, 2, and 3 as compared to control Group 4. 66.7% of patients in Group 4 required rescue analgesia at 24 h which was significantly higher (P < 0.0001) than that in Groups 1, 2, and 3 (26.67%, 20.00%, and 36.67%, respectively). Total number of analgesic doses required was only 32 in Group 3 as compared to Groups 2, 1, and 4, wherein it was 36, 40, and 78, respectively.Conclusion: Preemptive administration of ketamine decreases postoperative analgesic requirement with satisfactory hemodynamic stability and no side effects in 0.5 mg/kg dose