REMIFENTANIL VERSUS PROPOFOL AS ADJUNCTS TO REGIONAL ANESTHESIA

Study Objective: To compare the safety and efficacy of remifentanil an d propofol as adjuncts to regional anesthesia in patients undergoing o rthopedic or urogenital surgery. Design: Prospective, randomized study . Setting: Multicenter university hospitals. Patients: 107 ASA physica l status I, II, and III adult patients who underwent orthopedic or uro genital surgery with axillary, ankle, or spinal block. Interventions: Patients were randomized to receive either an infusion of remifentanil 0.2 mu g/kg/min or propofol 100 mu g/kg/min 5 minutes before nerve bl ock placement. The infusions were decreased by 50% on block completion , increased by 50% for patient discomfort, and decreased by 50% for hy poventilation (< 8 breaths/min) or hemodynamic instabilty. Measurement s and Main Results: Pain, discomfort, anxiety, and sedation were asses sed by both patient and investigator. Vital signs and adverse events w ere recorded. Fewer patients in the remifentanil group experienced pai n during block placement (6%), and were oversedated (7%) than patients in the propofol group (23% and 26%, respectively; p < 0.05). Hypovent ilation during and after block placement (21% and 25%, respectively) a nd nausea and vomiting during and after block placement (60% and 21%, respectively) were more common in the remifentanil group than in the p ropofol group (0% and 3%; 17% and 6%, respectively; p < 0.05). The inc idence of hypoventilation in remifentanil-treated patients was higher in patients over 65 years of age (p < 0.05), but was transient, resolv ing within minutes of discontinuing the infusion. Conclusions: At the doses studied, remifentanil was more effective than propofol in minimi zing pain without producing excessive sedation. Remifentanil was assoc iated with more transient respiratory depression and short-term nausea . Our findings indicate that the initial remifentanil rate should be 0 .1 mu g/kg/min (50% lower than the study's initial rate) and should be further decreased an additional 50% in the elderly to minimize advers e effects. (C) 1998 by Elsevier Science Inc.