Abstract

Post-spinal shivering is a common and distressing complication following spinal anesthesia, occurring in 40-70% of patients undergoing lower limb surgeries. This randomized, double-blind, placebo-controlled study aimed to compare the efficacy of ondansetron and palanosetron in preventing post-spinal shivering in patients undergoing lower limb surgeries under spinal anesthesia. A total of 180 patients aged 18-65 years, ASA physical status I-II, scheduled for elective lower limb surgeries were randomly allocated into three groups of 60 patients each: Group O received ondansetron 4 mg intravenously, Group P received palanosetron 0.075 mg/kg intravenously, and Group C received normal saline as placebo, all administered 15 minutes before spinal anesthesia. The primary outcome was the incidence of post-spinal shivering during the first 2 hours postoperatively. Secondary outcomes included severity of shivering, time to onset, hemodynamic parameters, and adverse effects. The incidence of post-spinal shivering was significantly lower in both treatment groups compared to placebo: Group O (18.3%), Group P (13.3%) versus Group C (63.3%) (p<0.001). Palanosetron demonstrated superior efficacy compared to ondansetron in preventing moderate to severe shivering (5.0% vs 11.7%, p<0.05). Both drugs effectively maintained hemodynamic stability without significant adverse effects. The mean time to onset of shivering was significantly delayed in both treatment groups. Both ondansetron and palanosetron are effective in preventing post-spinal shivering during lower limb surgeries, with palanosetron showing superior efficacy in preventing severe shivering episodes. Both drugs demonstrate excellent safety profiles and should be considered as prophylactic agents in patients at high risk for post-spinal shivering.