Remifentanil and controlled hypotension; comparison with nitroprusside or esmolol during tympanoplasty

Abstract

Purpose: To determine whether remifentanil, combined with propofol, could induce controlled hypotension, reduce middle ear blood flow (MEBF) measured by laser-Doppler flowmetry, provide a "dry" operative field, and could be compared with nitroprusside or esmolol combined with alfentanil and propofol. Methods: Thirty patients undergoing tympanoplasty and anesthetized with 2.5 mg·kg-1 propofol iv followed by a constant infusion of 120 μg·kg-1·min-1, were randomly assigned in three groups to receive either 1 μg·kg-1 remifentanil iv followed by a continuous infusion of 0.25 to 0.50 μg·kg-1·min-1, or nitroprusside iv, or esmolol iv combined for the latter two groups with alfentanil iv. Results: Controlled hypotension was achieved at the target pressure of 80 mmHg within 107 ± 16, 69 ± 4.4, 53.3 ± 4.4 sec for remifentanil, nitroprusside and esmolol respectively. MEBF decreased by 24 ± 0.3, 22 ± 3.3, 37 ± 3% and preceded the decrease in SABP, within 30 ± 6.1, 11.2 ± 3.1, 15 ± 2.8 sec for remifentanil, nitroprusside and esmolol respectively. Remifentanil, and nitroprusside decreased MEBF autoregulation less than esmolol (0.36 ± 0.1, 0.19 ± 0.2, -0.5 ± 0.2). Controlled hypotension was sustained in all three groups throughout surgery, and the surgical field rating decreased in a range of 80% in all three groups. Nitroprusside decreased pH and increased PaCO2. There were no postoperative complications in any of the groups. Conclusions: Remifentanil combined with propofol enabled controlled hypotension, reduced middle ear blood flow and provided good surgical conditions for tympanoplasty with no need for additional use of a potent hypotensive agent.