Study on anaesthetic agent propofol and sevoflurane as maintenance agent along with anti-emetic drug ondansetron in reducing post operative nausea and vomiting in high-risk patients.

BACKGROUND: Postoperative nausea and vomiting (PONV) remain among the most common and distressing complications following general anaesthesia, significantly affecting patient satisfaction, recovery times, and healthcare costs. Although ondansetron at a dose of 4 mg IV has long been considered the gold standard for PONV prophylaxis, emerging literature suggests that higher doses may improve efficacy in select high-risk populations. However, the relationship between ondansetron dose, anaesthetic regimen, and PONV incidence remains poorly defined, particularly when using a combination of propofol induction and sevoflurane maintenance. OBJECTIVE: This prospective observational study aimed to evaluate the incidence of early PONV (within the first two postoperative hours) following pre-induction administration of ondansetron 4 mg in patients receiving propofol-sevoflurane anaesthesia and to assess the influence of demographic and perioperative factors on emesis incidence. METHODS: One hundred fifty high-risk adult patients aged 18-60 years undergoing elective surgery under general anaesthesia were enrolled. All received ondansetron 4 mg IV during premedication, propofol for induction, and sevoflurane for maintenance. Episodes of nausea and vomiting were recorded at 30, 60, 90, and 120 min postoperatively. Statistical analyses included Mann-Whitney U tests for continuous variables and Fisher's exact tests for categorical data, with significance set at p < 0.05. RESULTS: A total of 150 patients were included in the analysis. The mean age of the cohort was 39.9 ± 13.1 years, with a predominance of female patients (63.3%). The overall incidence of early postoperative nausea and vomiting (within 120 min) was 9.3% (14/150). Most episodes were mild in severity, with only a small proportion of patients experiencing repeated vomiting. No statistically significant associations were identified between PONV and demographic variables such as age, sex, body mass index, smoking status, or prior history of PONV (p > 0.05). However, a higher proportion of PONV was observed among patients undergoing otorhinolaryngological procedures, although this did not reach statistical significance when analysed across all surgical departments. CONCLUSION: Ondansetron 4 mg IV administered pre-medication, combined with propofol induction and sevoflurane maintenance, effectively reduced early PONV incidence to 9.3% among high-risk adults. A higher incidence of PONV was observed in patients undergoing ENT procedures. These findings support the continued use of 4 mg as a sufficient and safe prophylactic dose for early postoperative periods, while underscoring the need for larger comparative studies evaluating dose-response relationships and late PONV outcomes.