Hormonal responses to high-dose fentanyl anaesthesia. A study in patients undergoing cardiac surgery.

The hormonal responses to anaesthesia and cardiac surgery were studied in 20 patients. Ten patients were anaesthetized with fentanyl 60 microgram kg-1 and nitrous oxide in oxygen and 10 with etomidate 0.3 mgkg-1 and nitrous oxide in oxygen plus halothane. There were no significant changes in cortisol, growth hormone or insulin concentrations in response to surgery in either group, although cortisol concentrations decreased during cardiopulmonary bypass. Both groups showed increases in prolactin concentrations. Patients anaesthetized with etomidate and halothane showed a significant increase in adrenaline and glucose concentrations not seen in the fentanyl group. Cardiopulmonary bypass was associated with marked increases in catecholamines in both groups.