Prevention of Shivering during Spinal Anesthesia: Comparison between Tramadol, Ketamine and Ondansetron

Introduction: Shivering is an unpleasant experience after spinal anesthesia. We conducted this study to evaluate the efficacy of ondansetron, ketamine and tramadol for prevention of shivering. Methods: In this randomized controlled study, 120 patients aged 18-65 years of American Society of Anesthesiologist (ASA) physical status I and II undergoing various surgical procedures were included and allocated alternately to one of the 4 groups; Normal saline (Group1), Ondansetron 4mg (Group2), Ketamine 0.25mg/kg (Group3) and Tramadol 0.5mg/kg (Group4). Incidence of shivering, effect on hemodynamics, nausea, vomiting, sedation and emergence reactions were recorded. Data was analyzed using SPSS (The Statistical Package for Social Sciences) version 20.0 software. Results: The patients were comparable in terms of demographic variables, baseline temperature, type of surgery, median level of sensory blockade, duration of surgery and anesthesia. Shivering was present in 17 (56.7%), 5 (16.7%), 3 (10%) and 3 (10%) patients respectively in Group 1, 2, 3 and 4 which was statistically significant when compared to Group 1 (P=0.00) The odds of NS and ondansetron, NS and ketamine, NS and tramadol was 6.53, 11.76 and 11.76 respectively which showed that study drugs were effective in preventing shivering. None of the patients were sedated in Group 1 and 2. Mild to moderate sedation was present in Group 3 and 4 (P=0.00). None of the patients had drug related adverse reactions. Conclusions: Prophylactic use of ondansetron, low doses of ketamine and tramadol is effective in preventing shivering post spinal anesthesia without untoward effects.