Sufentanil to supplement nitrous oxide in oxygen during balanced anaesthesia

Sufentanil in doses of 0.4 and 1.0 microgram/kg was used as an analgesic supplement to nitrous oxide-oxygen anaesthesia in 28 patients whose lungs were ventilated during body surface or lower abdominal surgery. Significant decreases in arterial blood pressure followed drug administration (mean 35.6%). Decreases in arterial pressure of greater than 30% occurred in 5 out of 14 patients in the low dose group, and 12 out of 14 in the high dose sufentanil group. There was a blunting of the pressor response to laryngoscopy and intubation after sufentanil. Increases in blood pressure were seen in both treatment groups at the onset of surgery. The peak responses were 27% increase in mean arterial pressure in the low dose group, and 51% increase in the 1.0 microgram/kg group. There was however no significant change in heart rate. Fourteen patients (8 in the low dose group) required volatile supplementation during surgery for clinical signs of inadequate anaesthesia. This occurred between 21 and 70 minutes after sufentanil administration, and plasma drug concentrations 0.06 and 0.54 ng/ml. Tracheal extubation was successfully achieved at the end of surgery in 26 out of 28 patients at plasma sufentanil concentrations which ranged from 0.03 to 0.37 ng/ml. The two remaining patients, neither of whom had received additional volatile supplementation, required naloxone to overcome postoperative ventilatory depression. No cases of intra-operative awareness were noted.