The effect of ondansetron on the analgesic efficacy of tramadol for postoperative patient-controlled intravenous analgesia / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of ondansetron on the analgesic efficacy of tramadol for postoperative patient-controlled intravenous analgesia (PCIA). Methods Forty ASA I - II patients aged 22-74 years, weighing 40-90 kg scheduled for radical mastectomy were randomly allocated to one of two groups control group ( n = 20) and ondansetron group ( n = 20) . The patients were premedicated with intramuscular atropine 0.01 mg?kg-1 and diazepam 0.2 mg?kg-1. Anesthesia was induced with midazolam 0.1-0.2 mg (total dose was limited to 15 mg), fentanyl 2.4?g?kg-1 , propofol 1.5-2.0 mg?kg-1 and vecuronium 0.12-0.15 mg?kg-1 . The patients were mechanically ventilated after tracheal intubation (VT 8-10 ml?kg-1 , RR 13 bpm). Anesthesia was maintained with enflurane inhalation and continuous infusion of vecuronium. The patients were attached to a PCIA pump after operation and received PCIA with 1 % tramadol (background infusion 2 ml?h-1 , bolus dose 2 ml, lockout interval 10min) in both groups. In ondansetron group the patients received ondansetron 6 mg iv during operation and a loading dose of tramadol 1 mg?kg-1 and ondansetron 2 mg after operation before PCIA. Pain score (VAS 0-10), sedation score (0-3), tramadol consumption and the incidence of nausea and vomiting were recorded at 4, 8, 12 and 24 h after operation. Results There was no significant difference in pain and sedation scores and the incidence of vomiting between the two groups. Significantly more tramadol was consumed at 4, 8 and 12 h after operation in the ondansetron group as compared with control group (P