Hormonal response in thoracic surgery. Effects of high-dose fentanyl anesthesia, compared to halothane anesthesia.

Thirty two patients undergoing cardiac thoracic surgery were randomly assigned into two groups: Patients of the first group received high dose fentanyl (50 micrograms/kg) at the induction and patients of the second group received halothane for the maintenance of anesthesia. All patients received N2O:O2 and pancuronium for muscle relaxation. Surgical stress, as evaluated by changes in blood pressure, heart rate, plasma cortisol and glucose levels, appeared in the halothane group but not in the fentanyl group. Postoperative respiratory depression was expressed usually by mild elevation of pCO2 in the fentanyl group. Nevertheless two of these patients presented hypoventilation requiring intubation and naloxone administration. High dose fentanyl anesthesia may prove to be very useful in non cardiac thoracic surgery as it protects the patient from the stress of the operation and assures prolonged postoperative analgesia. When this technique is used one must always anticipate postoperative mechanical ventilation.