Effects of ondansetron administered with different stage on postoperative nausea and vomiting induced by patient controlled intravenous analgesia with tramadol

Objective To evaluate effects of ondansetron administered with different time on postoperative nausea and vomiting(PONV) induced by patient controlled intravenous analgesia(PCIA) with tramadol.Methods Ninty ASA Ⅰ~Ⅱpatients undergoing lower limb surgery under continuously epidural anesthesia were randomly allocated into three groups(30 cases each group):group Ⅰ(without ondansetron),group Ⅱ(ondansetron then tramadol),and group Ⅲ(tramadol then ondansetron).PCIA were administered at the end point of operations.The incidence of PONV was observed in 48 hours postoperatively.Results The incidence of PONV in group Ⅱ was significant lower than group Ⅰ and group Ⅲ(P0.05),but there was no significant difference between group Ⅰ and group Ⅲ(P0.05).Conclusion Ondansetron administered before tramadol injection can prevent PONV induced by PCIA with tramadol,but administered after tramadol injection has no obvious effect.