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

Purpose: To determine whether remifentanil, combined with propofol, could i nduce controlled hypotension, reduce middle ear blood flow (MEBF) measured by laser-Doppler flowmetry, provide a "dry" operative field, and could be c ompared 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 mug.kg(-1.)mi n(-1), were randomly assigned in three groups to receive either 1 mug.kg(-1 ) remifentanil iv followed by a continuous infusion of 0.25 to 0.50 mug.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 m mHg within 107 +/- 16, 69 +/- 4.4, 53.3 +/- 4.4 sec for remifentanil, nitro prusside 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 e smolol (0.36 +/- 0.1, 0.19 +/- 0.2, -0.5 +/- 0.2). Controlled hypotension w as sustained in all three groups throughout surgery, and the surgical field rating decreased in a range of 80% in all three groups. Nitroprusside decr eased pH and increased PaCO2. There were no postoperative complications in any of the groups, Conclusions: Remifentanil combined with propofol enabled controlled hypoten sion, reduced middle ear blood flow and provided good surgical conditions f or tympanoplasty with no need for additional use of a potent hypotensive ag ent.