J.L. Paterson

Effects of high‐dose fentanyl anaesthesia on the established metabolic and endocrine response to surgery

The effect of the administration of fentanyl 50 μg/kg body weight on the established metabolic response to pelvic surgery was investigated. In comparison with a control group of patients in whom anaesthesia was supplemented with halothane, fentanyl was associated with a significant decrease in only blood lactate concentrations and heart rate. There were no significant differences in blood glucose, plasma non‐esterified fatty acids, and plasma cortisol values between the two anaesthetic techniques. It is concluded that the administration of high‐dose fentanyl has little effect on the established metabolic response to surgery, compared with the marked changes observed when the same dose is given before the onset of surgical stimulation.

Fentanyl and the metabolic response to gastric surgery

The effect of the supplementation of nitrous oxide‐oxygen anaesthesia with either 50 μg fentanyl/kg body weight or 0·5–1·0% halothane on the metabolic and hormonal response to gastric surgery was investigated in 16 patients. Those patients who received fentanyl showed a significant decrease (p<0·05) in the hyperglycaemic response to surgery after 30 and 90 minutes and a significant decrease (p<0·05) in the plasma cortisol response after 30 minutes. Profound respiratory depression occurred at the end of surgery in all patients who were given fentanyl. This required the intravenous administration of naloxone and careful supervision in the early postoperative period. It is concluded that the transient metabolic and endocrine benefits produced by fentanyl do not compensate for the severe respiratory problems postoperatively and thus ‘high‐dose fentanyl’ cannot be recommended for upper abdominal surgery.

Epidural diamorphine and the metabolic response to upper abdominal surgery.

The effect of the administration of diamorphine 10 mg epidurally on the metabolic response to cholecystectomy was investigated and compared with a control group of patients given intravenous papaveretum. There were no significant differences in blood glucose, lactate and pyruvate, and plasma nonesterified fatty acid values between the epidural diamorphine group and the control group. Plasma cortisol concentrations were significantly lower in the epidural diamorphine group postoperatively and this was associated with a marked improvement in pain relief. We conclude that epidural opiates do not directly influence the metabolic response to surgery, but decrease the cortisol response postoperatively secondary to improved analgesia.

Hormonal and metabolic responses to cardiac surgery with sufentanil‐oxygen anaesthesia

The effects of sufentanil, 10 and 20 μg kg‐1 on the hormonal and metabolic responses to coronary artery surgery were compared in 20 patients. The most important finding was that the changes in circulating β‐ endorphin, ACTH, cortisol, GH, glucose, lactate and glycerol concentrations during and after cardiac surgery were similar with both doses of sufentanil. Although sufentanil prevented a significant increase in plasma β‐endorphin, ACIH and cortisol values until 6 h after cardiopulmonary bypass (CPB), a significant increase in GH secretion occurred with the onset of CPB. Plasma insulin concentrations declined significantly after 30 min CPB, but recovered after 60 min CPB with the restoration of normothermia. Blood glucose values did not change during surgery before CPB, but started to rise with the onset of CPB and continued to increase significantly in the postoperative period. Changes in blood lactate and plasma glycerol concentrations primarily reflected the load of CPB and the effects of heparin, respectively. The results show that increasing the dose of sufentanil up to 20 μg kg‐1 does not result in better suppression of the endocrine and metabolic changes associated with cardiac surgery.