Comparing the effect of Ondansetron versus combined Ondansetron and Dexamethasone for prophylaxis postoperative nausea and vomiting in elective cesarean section receiving intrathecal morphine in Buddhasothorn Hospital : RCT ,double-blind, Phase II

Abstract

Background: Postoperative nausea and vomiting (PONV) is common issue in cesarean section patients  receiving spinal anesthesia with intrathecal morphine. Prophylactic use of antiemetics is more effective than treating them symptoms after onset.

Objective: To compare the incidence of PONV between patients receiving Ondansetron alone and those receiving Ondansetron combined with Dexamethasone. Secondary objectives included duration of stay in the recovery room, postoperative pain score, and Metoclopramide use within 24 hours postoperatively.

Methodology: A randomized, double-blind study was conducted with 80 patients divided into two groups of 40. Group O received Ondansetron 4 mg, while Group OD received combination of Ondansetron 4 mg and Dexamethasone 5 mg. Data on PONV and antiemetic use were collected from the operating room, recovery room, and inpatient ward. Recovery room duration and pain levels at 24 hours were recorded. Statistical analysis was performed using the Chi-square test and SPSS version 29.0.1.

Results: The incidence of PONV within 24 hours was 27.5% in Group O and 20.0% in Group OD (P = 0.43), showing no statistically significant difference. However, pain severity differed significantly between the groups, with Group OD experiencing less severe pain (P = 0.032).

Conclusion: The combination of Ondansetron and Dexamethasone was more effective in reducing the incidence and severity of PONV compared to Ondansetron alone, although the difference was not statistically significant. However, the combination significantly reduced the severity of postoperative pain.