Does sufentanil concentration influence isoflurane requirements during coronary artery bypass grafting?

To search for concentration-related suppression of hemodynamic responsiveness by sufentanil.

Prospective, randomized, double-blind study.

University hospital.

Patients undergoing elective coronary artery bypass grafting (CABG).

Patients were assigned to target effect-site sufentanil concentrations of 1.5 ng/mL (group L; n = 14), 3.0 ng/mL (group M; n = 13), or 4.5 ng/mL (group H; n = 12). Sufentanil was administered by computer-assisted continuous infusion. Isoflurane was used to maintain intraoperative hemodynamics near preoperative values.

Hemodynamics, the electroencephalographic spectral edge (SE95), and end-tidal isoflurane concentration (ET-ISO) were measured every 10 to 30 seconds during the prebypass period. Serum sufentanil concentration was measured at intervals. Prebypass serum sufentanil concentrations were stable, averaging 3.0 +/- 0.7, 5.1 +/- 1.1, and 7.1 +/- 1.3 ng/mL in groups L, M, and H, respectively. The groups did not differ with respect to the speed of induction, intraoperative hemodynamics, incidence of isoflurane use, or isoflurane concentrations required. ET-ISO and serum sufentanil levels were not correlated. Among seven group L patients who did not require isoflurane, the average prebypass serum sufentanil concentration ranged from 1.7 to 3.3 ng/mL.

Sufentanil does not induce concentration-related suppression of hemodynamic responsiveness over the range studied. A stable serum sufentanil concentration of 3.0 +/- 0.7 ng/mL induces the maximal opioid effect and need not be exceeded in patients undergoing CABG. A sufentanil concentration of 1.7 ng/mL provides clinically adequate anesthesia without supplementation in some premedicated patients undergoing CABG.