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

Objective: To search for concentration-related suppression of hemodynamic r esponsiveness by sufentanil. Design: Prospective, randomized, double-blind study. Setting: University hospital. Participants: Patients undergoing elective coronary artery bypass grafting (CABG). Intervention: Patients were assigned to target effect-site sufentanil conce ntrations 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-assiste d continuous infusion. Isoflurane was used to maintain intraoperative hemod ynamics near preoperative values. Measurements and Main Results: Hemodynamics, the electroencephalographic sp ectral edge (SE95), and end-tidal isoflurane concentration (ET-ISO) were me asured every 10 to 30 seconds during the prebypass period. Serum sufentanil concentration was measured at intervals. Prebypass serum sufentanil concen trations were stable, averaging 3.0 +/- 0.7, 5.1 +/- 1.1, and 7.1 +/- 1.3 n g/mL in groups L, M, and H, respectively. The groups did not differ with re spect to the speed of induction, intraoperative hemodynamics, incidence of isoflurane use, or isoflurane concentrations required. ET-ISO and serum suf entanil levels were not correlated. Among seven group L patients who did no t require isoflurane, the average prebypass serum sufentanil concentration ranged from 1.7 to 3.3 ng/mL. Conclusion: Sufentanil does not induce concentration-related suppression of hemodynamic responsiveness over the range studied. A stable serum sufentan il concentration of 3.0 +/- 0.7 ng/mL induces the maximal opioid effect and need not be exceeded in patients undergoing CABG. A sufentanil concentrati on of 1.7 ng/mL provides clinically adequate anesthesia without supplementa tion in some premedicated patients undergoing CABG. Copyright (C) 1999 by W .B. Saunders Company.