Efficacy of Intravenous Low-Dose Ketamine for Prevention of Post-Spinal Anesthesia Shivering in Cesarean Section: A Double-Blind, Randomized Controlled Study

Background: Post-spinal anesthesia shivering in cesarean section is a common complication owing to sympatholysis, resulting in vasodilation and heat redistribution from the core to peripheral parts of the body. The physiological consequences of shivering include an increase in cardiac and systemic energy expenditure, oxygen consumption, and carbon dioxide production. Ketamine, a N-methyl D-aspartate (NMDA) receptor antagonist, has been reported to have anti-shivering effects. The aim of this study is to determine the effectiveness of prophylactic low-dose intravenous (IV) ketamine (0.25 mg/kg) in preventing shivering after spinal anesthesia as compared to placebo in elective cesarean sections. Methods: A randomized, double-blind study was conducted on 80 patients aged 18 to 40 years and American Society of Anesthesiologists grade II undergoing elective cesarean section under spinal anesthesia. Groups K and group S received IV ketamine 0.25 mg/kg diluted to 5 ml in normal saline and 5 ml normal saline IV, respectively, 10 minutes after spinal anesthesia. The incidence and duration of shivering, tympanic membrane temperature, sedation score, hemodynamic parameters, and side effects were recorded. Results: The incidence of shivering in group K was 12.5% compared to 32.5% in group S ( P = 0.030). The mean duration of shivering was only 0.75 ± 2.02 min in group K as compared to 2.38 ± 3.57 min in group S ( P = 0.014). Mean arterial pressure and heart rate were stable in group K without any significant sedative effect. Conclusion: The use of prophylactic low-dose ketamine (0.25 mg/kg) significantly reduces the incidence and duration of spinal anesthesia-induced shivering compared to placebo.