The effectiveness of ondansetron compared to a placebo for preventing shivering in orthopedic surgery patients at Sanpatong Hospital: A double-blind randomized controlled trial

Abstract

Shivering is a common side effect of spinal anesthesia, increasing oxygen consumption, elevating cardiovascular risk, and potentially causing hypoxia. This study aimed to compare the incidence of shivering following spinal anesthesia for hip surgery between intravenous ondansetron and a placebo.

Methods: A parallel-group, double-blind, randomized controlled trial (RCT) was conducted in patients undergoing hip surgery under spinal anesthesia. Participants were aged 20–90 years, classified as ASA ≤ III, and afebrile. Exclusion criteria included admission body temperature <36.0°C or >37.8°C, hemodynamic instability, cardiac arrhythmia, aortic stenosis, or surgery duration >180 minutes. The study was conducted at Sanpatong Hospital from December 2023 to October 2024. A total of 232 patients were randomly assigned via computer-generated simple randomization to either the control group (0.9%NaCl 4 mL) or the intervention group (ondansetron 8 mg) administered intravenously. Patients, medical personnel, and outcome assessors were blinded.

Results: Of the 232 patients enrolled, 116 were assigned to the ondansetron group and 116 to the placebo group. After excluding 20 patients, 105 patients in the ondansetron group and 107 in the placebo group were analyzed. The proportion of male participants was 33.6% in the ondansetron group and 22.9% in the placebo group. The mean age was 72.99 ± 12.39 years in the ondansetron group and 71.69 ± 13.55 years in the placebo group. The mean BMI was 21.02 ± 3.82 kg/m² and 21.8 ± 4.58 kg/m², respectively. Baseline temperature was 36.71 ± 0.41°C in the ondansetron group and 36.76 ± 0.34°C in the placebo group. The only significant difference was in spinal anesthesia duration, which was shorter in the ondansetron group (105.00 ± 31.59 min) compared to the placebo group (120.95 ± 35.49 min, p = 0.001). Shivering occurred in 17.8% of the ondansetron group and 41.9% of the placebo group, with a difference of 24.15% (95% CI: -36.04, -12.25; p < 0.001). Hypotension was also less frequent in the ondansetron group (27.36%, p < 0.001). No other significant adverse effects were observed.

Conclusion: In patients undergoing hip surgery, intravenous ondansetron (8 mg) was effective in reducing the incidence of post-spinal anesthesia shivering (PSAS).