The Impact of Optimal Dose of Ketamine on Shivering Following Elective Abdominal Hysterectomy: A Randomised Comparative Study

Background: Following surgery, patients frequently suffer from shivering, and this can lead to postoperative complications and discomfort. Objectives: This study aimed to compare the effect of ketamine on patients’ shivering following an elective abdominal hysterectomy. Patients were given either Ketamine (0.25 mg or 0.5 mg/kg) or a placebo. The study and surgery took place in a subspecialty University Hospital for Gynecology and Obstetrics. Methods: This study was an interventional, randomized, controlled clinical trial. Ninety-six women who underwent elective abdominal hysterectomy were randomly assigned to three groups. Ketamine was administered to all participants 20 min prior to the end of surgery. The first group received 0.25 mg/kg of intravenous ketamine. The second group received 0.5 mg/kg intravenous ketamine. The third group received a placebo of intravenous saline. Postoperative shivering, sedation grade, hallucination, nausea, vomiting, and nystagmus were measured for each patient up to 30 minutes. Results: The study showed that patients suffered from less shivering in the two groups that received ketamine. The reduced shivering was seen 5, 10, and 20 min following surgery in the two groups that were given two doses of 0.25 and 0.5 mg/kg ketamine compared to the control group (P value < 0.05). There was a significant difference between patients receiving normal saline and those having 0.25 and 0.5 mg/kg of ketamine in the rate of sedation grade, nausea, vomiting, and nystagmus (P value < 0.05). The main differences in patients receiving ketamine were the sedation grade at zero time and postoperative hallucination experienced by those patients who received 0.5 mg/kg of ketamine. Conclusions: Ketamine reduced shivering in all patients following elective abdominal hysterectomy. This was regardless of dose. Patients were less likely to suffer from hallucinations and sedation grade with a lower dose of ketamine (0.25 mg/kg compared to 0.50 mg/kg).