Remifentanil induces consistent and sustained controlled hypotension in children during middle ear surgery

To determine in children whether remifentanil combined with sevoflurane, could induce controlled hypotension, reduce middle ear blood flow (MEBF) measured by laser-Doppler, and provide a satisfactory operative field.

Forty children undergoing middle ear surgery and anesthetized with sevoflurane were randomly assigned to receive either 1 micro g x kg(-1) remifentanil iv followed by a continuous infusion of 0.2 to 0.5 micro g x kg(-1) x min(-1) or 0.25 micro g x kg(-1) x min(-1) nitroprusside iv and alfentanil iv (n = 20 in each group).

Controlled hypotension was achieved at the target mean arterial pressure (MAP) of 50 mmHg (P < 0.01) within 121 +/- 21 and 62 +/- 9 sec for remifentanil and nitroprusside respectively. MEBF decreased by 22 +/- 4 and 20 +/- 6% and preceded the decrease in MAP within 20 +/- 7 and 10 +/- 3 sec for remifentanil and nitroprusside respectively. Remifentanil, and nitroprusside decreased MEBF autoregulation (0.41 +/- 0.2 and 0.37 +/- 0.3 respectively). Controlled hypotension was sustained in both groups throughout surgery, and the surgical field rating was good. Nitroprusside increased PaCO(2) slightly, and there were no postoperative circulatory, neurological or metabolic complications in any of the groups.

Remifentanil combined with sevoflurane in children enabled controlled hypotension, reduced MEBF and provided good surgical conditions for middle ear surgery with no need for additional use of a specific hypotensive agent.