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

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.

Thirty patients undergoing tympanoplasty and anesthetized with 2.5 mg x kg(-1) propofol iv followed by a constant infusion of 120 microg x kg(-1) x min(-1), were randomly assigned in three groups to receive either 1 microg x kg(-1) remifentanil iv followed by a continuous infusion of 0.25 to 0.50 microg x kg(-1) x min(-1), or nitroprusside iv, or esmolol iv combined for the latter two groups with alfentanil iv.

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.

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.