Evaluation of sufentanil anesthesia obtained by a computer-controlled infusion for cardiac surgery

To determine the "therapeutic window" for sufentanil in cardiac surgery, nine hemodynamically stable, lightly premedicated patients were anesthetized with sufentanil to undergo coronary artery bypass grafting. Sufentanil was administered by a computer-controlled infusion pump programmed with an infusion scheme based on average sufentanil pharmacokinetics. The presence of somatic or hemodynamic responses to tracheal intubation, skin incision, sternotomy, and during electrocauterization, to isolate the internal mammary artery were correlated with plasma concentrations of sufentanil. The concentration versus response/no response relationships were analyzed by application of the logistic (Hill) equation. The CP50 of sufentanil to suppress responses to intubation, incision, and sternotomy was 7.1 ng/mL and for mediastinal dissection it was 12.7 ng/mL. Interpatient variability was as much as that reported previously for other opioids in other types of surgical patients. The computer-controlled infusion scheme consistently produced sufentanil plasma concentrations in excess of the target concentrations, but there was a strong correlation between target and actual sufentanil concentrations (r = 0.88, P < 0.05).