Comparison of Intravenous Ketamine Dosages for Postoperative Analgesia: Efficacy and Adverse Reactions in Abdominal Hysterectomy

Abstract

Introduction: Following an abdominal hysterectomy, preemptive analgesia with two intravenous ketamine injections has been used as multimodal analgesia for postoperative pain. Ketamine’s ideal dosage for postoperative analgesia that has the least amount of adverse reactions is still up for discussion. Materials and Methods: This investigation was conducted at M.G.M. Medical College and M.Y. Hospital, Indore. The study included a total of 90 participants, classified as the American Society of Anesthesiologists classes 1 and 2, within the age range of 18–65 years. There were three groups made after dividing the patients with the help of the chit method so that no preference could be done. Group A was given an intravenous ketamine injection of 0.3 mg/kg, Group B was given an intravenous ketamine injection of 0.2 mg/kg, and Group C then got an intravenous ketamine injection of 0.1 mg/kg. In addition, all groups received subsequent 0.1 mg/kg ketamine injections every 30 min until the completion of the surgery. Various parameters were recorded for 24 h following the procedure, including the time to the first dosage, combined dose of rescue analgesia, combined number of doses of rescue analgesia, and incidence of adverse reactions. Results: The demographic profiles of all three groups were found to be comparable. The average time to request the first dosage of rescue analgesia was 316.33 ±66.345, 230± 44.721 & 89 ±26.698 minutes and 89 min, respectively, in Groups A, B, and C. Group A exhibited a significantly longer duration compared to Groups B and C. Postoperatively, at the 24-h mark, Group A displayed the lowest mean pain score (Visual Analog Scale) compared to Group B and Group C, with a statistically significant difference observed at P = 0.05. However, the frequency of nausea and vomiting between Groups A and B, as well as C, was not significant. Conclusion: Patients undergoing abdominal hysterectomy under spinal anesthesia experience reduced postoperative discomfort when administered intravenous ketamine at a dosage of 0.3 mg/kg, as opposed to lower doses. These results emphasize the potential benefits of higher dosage administration in enhancing postoperative analgesia in such procedures.