Comparison of fentanyl and halothane supplementation to general anaesthesia on the stress response to upper abdominal surgery.

The stress response to surgery and anaesthesia was studied in 20 patients undergoing cholecystectomy or vagotomy and pyloroplasty. Patients were anaesthetized with thiopentone and nitrous oxide; 10 patients received supplements of 0.5-1.5% halothane and the others fentanyl (mean 17 micrograms kg-1). The plasma concentrations of cortisol and glucose increased in both groups during surgery and remained greater than baseline immediately following recovery of consciousness. The hyperglycaemic response in the halothane group was greater than in the fentanyl group. Plasma noradrenaline concentrations increased in the group receiving halothane, but did not increase significantly in the group receiving fentanyl.