The Effect of Forced-Air Warmer, Ondansetron or their Combination on Shivering in Pregnant Women Coming for Elective Cesarean Section under Spinal Anesthesia: A Prospective, Randomized Controlled Comparative Study

CONTEXT: Perioperative shivering can occur in up to 85% of patients undergoing cesarean section under spinal anesthesia. It has many detrimental effects and disrupts early mother-child bonding. Therefore, it should ideally be prevented by either pharmacologic or nonpharmacological means. AIMS: The primary aim of this study was to evaluate the efficacy of intraoperative forced-air warming, ondansetron or their combination in preventing perioperative shivering in patients undergoing elective cesarean section under spinal anesthesia. SETTINGS AND DESIGN: A prospective randomized controlled comparative study done at the tertiary care center. SUBJECTS AND METHODS: A total of 120 patients undergoing elective cesarean section under spinal anesthesia were randomly assigned to three groups. Group O received ondansetron 4 mg intravenously (i.v.) after giving block with no forced air warming. Group W received forced-air warming intraoperatively. Group C received ondansetron 4 mg i.v. after giving block plus intraoperative forced-air warming. Core temperature (tympanic membrane) and the arm skin temperature were measured and shivering was graded simultaneously. STATISTICAL ANALYSIS USED: Parametric data were analyzed using one-way ANOVA and Student's paired t-test where ever appropriate. Nonparametric data were analyzed using the Kruskal–Wallis and the Chi-square test. Values of P < 0.05 were considered statistically significant. RESULTS: Shivering incidence was higher in Group O and Group W being 17.5% and 20%, respectively, and least in Group C being 5%. The incidence of Grade ≥3 shivering requiring rescue drug was lower in Group C (2.5%) compared to that of the Groups W (5%) and O (10%) but was not statistically significant (P = 0.21). CONCLUSIONS: Combined use of ondansetron and forced- air warmer was more effective in reducing the incidence of shivering in pregnant women during elective cesarean section than when used individually.