Prophylactic Role of Ketamine and Dexmedetomidine on the Prevention of Shivering in Patients Undergoing Inguinal Herniorrhaphy by Spinal Anesthesia: A Randomized Clinical Trial

Abstract

Background: Numerous medical interventions have been utilized to prevent postoperative shivering. Due to the potential complications associated with the use of pethidine, such as respiratory failure, the exploration of alternative drugs for the prevention and treatment of postoperative shivering has been a key consideration. Objectives: The aim of this study was to assess the preventive effects of ketamine and dexmedetomidine on shivering in patients undergoing inguinal herniorrhaphy under spinal anesthesia. Methods: This triple-blind randomized clinical trial involved patients who were candidates for inguinal herniorrhaphy with spinal anesthesia. Patient, investigator/administering, and outcome assessor were blinded. The necessary sample size was 150, estimated based on statistical formula at a 95% confidence interval and 80% power. Patients were randomly assigned using a computer-generated random sequence allocation and a randomized block sampling design with block sizes of six to ensure balanced allocation across the three groups: Ketamine, dexmedetomidine, and control. Randomization was performed using random sequence allocation software and randomized block sampling with 6 blocks for all 3 treatment groups. The severity of shivering was assessed using the Bedside Shivering Assessment Scale (BSAS) at multiple time points: Immediately, 5, 15, and 30 minutes after spinal anesthesia, and upon entering the recovery room, 15 minutes later, and at discharge from recovery. Data were analyzed using IBM SPSS Statistics version 21 software. Quantitative data were expressed as mean ± standard deviation, while qualitative data were presented as percentages. The mean of the variables was compared using Student's t-test, and the chi-square test was employed to compare qualitative data. Results: The severity of shivering was notably lower in the dexmedetomidine group at 5, 15, and 30 minutes after spinal anesthesia induction, during recovery, and 15 minutes after recovery. The intensity of shivering upon exiting recovery was similar in the ketamine and dexmedetomidine groups and significantly lower than in the control group. Systolic blood pressure was significantly lower in the dexmedetomidine group upon entry into recovery and 15 minutes after recovery. Throughout all time periods, patients in the dexmedetomidine group exhibited significantly lower heart rates. Conclusions: Both ketamine and dexmedetomidine proved effective in reducing post-herniorrhaphy shivering compared to the control group, with the effect being notably greater in the dexmedetomidine group.