Early vs late intraoperative administration of tropisetron for the prevention of nausea and vomiting in children undergoing tonsillectomy and/or adenoidectomy

Background: Tropisetron is a long-acting 5HT(3) receptor antagonist and was shown to be effective in the prevention of postoperative nausea and vomiting (PONV) after tonsillectomy. The aim of the study was to compare the effects of early vs late intraoperative administration of tropisetron with regard to prevention of PONV during the first 48 h after extubation. Methods: In a randomized double-blind study, we investigated 120 children aged 1-12 years undergoing general anesthesia for tonsillectomy or adenotonsillectomy. Patients received 0.1 mg.kg(-1) tropisetron (maximum 2 mg) immediately after inhalational induction (early) and establishment of intravenous access or after the end of surgery before extubation (late). PONV and the need for antiemetic rescue medications were recorded within the following 48 h. Patient data were analyzed using t-test, chi-squared test (significance level of alpha = 0.05) and Spearman rank correlation test. Results: The overall incidence of vomiting was 55.3%, with 60% (36/60) in the early treatment and 51.6% (31/60) in the late treatment group (P = 0.46). The observed time course 48 h postoperatively showed no difference regarding the number of vomiting episodes between the two groups and the need for antiemetic rescue medication. The incidence of nausea was higher in the late application group in the first 6 h after extubation (P = 0.001) and higher in the early application group between 24 and 48 h after extubation (P = 0.02). Morphine and the age over 3 years had a strong influence on the incidence of vomiting. Conclusion: The intraoperative time point (early vs late) of intravenous administration of a single prophylactic dose of tropisetron has no impact on the incidence of PONV during the first 48 h after tonsillectomy and/or adenoidectomy in children.