OBJECTIVETo compare the efficacy and safety of remifentanil and fentanyl in patients undergoing a modified radical mastectomy or total hysterectomy.

METHODSFifty-four patients were evenly randomised into remifentanil group and fentanyl group. Anesthesia was induced by propofol (1 - 2 mg/kg) and either remifentanil (2 microg/kg) or fentanyl (2.5 microg/kg), and was maintained with inhalation of nitrous oxide in oxygen (2:1) and continuous infusion of either remifentanil (0.2 microg.kg(-1).min(-1)) or fentanyl (0.03 microg.kg(-1).min(-1)).

RESULTSThe number of patients exhibiting light anesthesia responses in the remifentanil group during intubation and the maintenance of anesthesia was significantly less than that in the fentanyl group. Both systolic and diastolic blood pressures in the fentanyl group were significantly higher than those in the remifentanil group during intubation, skin incision, maintenance of anesthesia and extubation. The time to opening eyes on command and the time for extubation after surgery was comparable between the two groups. More patients in the remifentanil group (25 patients) required bolus injection of morphine for postoperative pain relief than those in the fentanyl group (5 patients, P < 0.05). There was no significant difference between the two groups in terms of side effects.

CONCLUSIONSUnder the condition of this study protocol, the anesthetic and analgesic effects of remifentanil are more potent than those of fentanyl. Remifentanil can offer superior intraoperative hemodynamic stability in comparison with fentanyl, and has no compromising recovery from anesthesia.