EVALUATION OF SUFENTANIL ANESTHESIA OBTAINED BY A COMPUTER-CONTROLLEDINFUSION FOR CARDIAC-SURGERY

To determine the ''therapeutic window'' for sufentanil in cardiac surg ery, nine hemodynamically stable, lightly premedicated patients were a nesthetized with sufentanil to undergo coronary artery bypass grafting . Sufentanil was administered by a computer-controlled infusion pump p rogrammed with an infusion scheme based on average sufentanil pharmaco kinetics. The presence of somatic or hemodynamic responses to tracheal intubation, skin incision, sternotomy, and during electrocauterizatio n, to isolate the internal mammary artery were correlated with plasma concentrations of sufentanil. The concentration versus response/no res ponse 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 dissectio n it was 12.7 ng/mL. Interpatient variability was as much as that repo rted previously for other opioids in other types of surgical patients. The computer-controlled infusion scheme consistently produced sufenta nil plasma concentrations in excess of the target concentrations, but there was a strong correlation between target and actual sufentanil co ncentrations (r = 0.88, P < 0.05).