Background and Goal of Study: The use of volatile anaesthetics may be the main cause of early (0-2 h) postoperative vomiting but not delayed (2-24 h) postoperative vomiting (1). Midazolam may have effect in decreasing postoperative nausea and vomiting (PONV) incidence following general anaesthesia (2). We compared the prophylactic antiemetic effects of ondansetron, propofol, and midazolam for ambulatory surgery patients.
Materials and Methods: In this prospective, randomized, placebo-controlled trial, we studied 180 female patients scheduled for ambulatory surgery under inhalation (sevoflurane) induction and maintenance of anaesthesia with laryngeal mask airway (LMA). The patients received ondansetron (Ond) 4mg, propofol (Prop) 0.5mg/kg, midazolam (Mid) 0.04mg/kg, or saline (Sa) IV 30 min before the end of surgery. Our primary efficacy end point was complete response (CR; no PONV, no rescue antiemetic) 0-2 h or 2-24 h postoperatively. Sample size calculation was performed before starting the trials by using a statistical power analysis (N = 40). Data were analyzed using Fisher's exact test, Chi square test with Yates' correction, Mantel-Haenszel test and Wilcoxon's ranked sum test as appropriate.
Results: Data [mean (SD) or number (%)] are shown in the Table:
Conclusion(s): After using sevoflurane for induction and maintenance of anaesthesia with LMA:
- midazolam group has a lower incidence of nausea and a higher complete response rate than other groups (0-2 h);
- the anti-vomiting effects (0-2 h) and the incidence of PONV (2-24 h) were no difference among groups.
1 Apfel CC, Kranke P, Katz MH, et al. Br J Anaesth
2 Bauer KP, Dom PM, Ramirez AM, et al. J Clin Anesthesia