Comparison of different methods of administering tropisetron in patient-controlled analgesia in the prevention of postoperative nausea and vomiting

Objective To evaluate the different methods of administering tropisetron in patient-controlled analgesia(PCA) with tramadol in the prevention of postoperative nausea and vomiting.Methods Two hundred and forty ASA class Ⅰ or Ⅱ patients scheduled for selective abdominal surgery under general anesthesia were enrolled in this study. At the end of surgery, all patients received PCA with tramadol (9mg/ml,bolus dose 18mg, continuous dose 9mg/h and lockout interval 15min).The patients were randomly divided into 4 groups with 60 cases each. Before commencement of PCA, the patients received no tropisetron(groupⅠ), tropisetron 5mg immediately(groupⅡ), tropisetron 2mg immediately and tropisetron 3mg in PCA pump(group Ⅲ), and tropisetron 5mg in PCA pump(groupⅣ).Incidence of nausea and vomiting and side effects were recorded at 2, 4, 8, 36 and 48h after operation. Results (1)In groupⅡand group Ⅲ,the incidences of nausea were reduced significantly compared with those in groupⅠ(P0.05). (2) In groupⅡand group Ⅲ, the incidences of vomiting were reduced significantly compared with those in groupⅠat 2, 4, 8 and 36h(P0.05). In addition, the incidence of vomiting was reduced significantly in group Ⅲ compared with that in group Ⅱ at 48h(P0.05). Conclusion The strategy of intravenous tropisetron 2mg after the surgery and 3mg in PCA pump is better than that of intravenous tropisetron 5mg in reducing the incidence of PONV associated with the use of PCA tramadol. Tropisetron 5mg given in PCA pump could not prevent postoperative nausea and vomiting.