Comparison of the effect of adding remifentanil to patient-controlled tramadol or morphine for postoperative analgesia after major abdominal surgery.

Objective: In this study, the authors investigated the effect of the addition of remifentanil to tramadol or morphine for patient-controlled analgesia (PCA).

Design: Prospective, randomized, double-blind, controlled study.

Setting: University Hospital.

Patients, Participants: The authors randomly allocated 133 patients undergoing major abdominal surgery to receive IV PCA with tramadol alone, tramadol plus remifentanil, morphine alone or morphine plus remifentanil.

Interventions: Bolus doses of tramadol (0.2 mg/kg), tramadol (0.2 mg/kg) plus remifentanil (0.2 microg/kg), morphine (0.02 mg/kg), or morphine (0.02 mg/kg) plus remifentanil (0.2 microg/kg) were available every 10 minutes without time limit or background infusion.

Main Outcome Measure(s): Discomfort, sedation, pain scores, side effects, and total and bolus tramadol and morphine consumption were recorded for up to 24 hours after the start of PCA.

Results: Pain scores at rest and movement were greater with tramadol alone than in the other groups at 1, 2, and 6 hours (p < 0.0125). The addition of remifentanil reduced cumulative tramadol consumption at 6, 12, and 24 hours, but not morphine consumption. More patients required supplementary rescue analgesia with meperidine, and with greater dosage, with tramadol alone (p < 0.001), and the incidence of nausea was greater with tramadol alone. The addition of remifentanil not only significantly improved discomfort scores in remifentanil groups, but also increased the degree of sedation in morphine-remifentanil group.

Conclusions: After major abdominal surgery, adding remifentanil to PCA tramadol resulted in better pain scores, lower analgesic consumption, and fewer side effects when compared with tramadol alone. However, analgesic outcome with remifentanil was not prominent in MR group as much as in TR group.