Tropisetron plus subhypnotic propofol infusion is more effective than tropisetron alone for the prevention of vomiting in children after tonsillectomy

This study evaluated the efficacy of tropisetron compared with tropisetron and a subhypnotic propofol infusion in preventing postoperative vomiting following tonsillectomy. One hundred and forty healthy children, aged four to 12 years, undergoing tonsillectomy were recruited in a randomised, double-blind study. After induction with sevoflurane, anaesthesia was maintained with sevoflurane and nitrous oxide. All patients received tropisetron (0.2 mg/kg up to 5 mg; intravenously) and fentanyl (2 mu g/kg; intravenously) and were intubated after atracurium which was reversed with neostigmine (and atropine). The tropisetron-plus-propofol group received a single dose of propofol (1 mg/kg) before intubation and a continuous infusion of propofol throughout surgery at 15 mu g/kg/min. Data for postoperative vomiting were grouped into zero to four and four to 24 hour time intervals. A P value of <0.05 was considered statistically significant. The percentage of patients exhibiting a complete response (no retching or vomiting for 24 hours) was 47.1% (33170) in the tropisetron-alone group and 72.8% (51/70) in the tropisetron-plus-propofol group (P=0.002). The 0.257 absolute risk reduction of vomiting with the addition of propofol represents a number needed to treat of 3.87, and a risk ratio of 0.51 (95% CI 0.32 to 0. 79). Significantly fewer patients vomited in the tropisetron-plus-propofol group than in the tropisetron-alone group during the zero to four post-surgery interval (P=0.016), but the difference was not statistically significant for the four to 24 hour postoperative period (P=0.116). Intraoperative subhypnotic propofol infusion combined with tropisetron is more effective than tropisetron alone in reducing postoperative vomiting after tonsillectomy in children.