Stress responses in three different anesthetic techniques for carbon dioxide laparoscopic cholecystectomy

Abstract

Study objective: To evaluate and compare the stress hormone responses during laparoscopic cholecystectomy during general anesthesia, general anesthesia supplemented by fentanyl, and general anesthesia combined with epidural anesthesia.

Design: Prospective, randomized clinical study.

Setting: Operating rooms at a municipal hospital.

Patients: 52 ASA physical status I and II patients.

Interventions: Anesthesia was induced slowly with sevoflurane and nitrous oxide (N2O) in oxygen (O2) by mask. Endotracheal intubation was facilitated with intravenous (i.v.) vecuronium 0.1 mg/kg. In 17 patients, anesthesia was maintained with sevoflurane and 50% N2O in O2. For another 18 patients, fentanyl 4 micrograms/kg was administered after endotracheal intubation, and anesthesia was maintained with sevoflurane and 50% N2O in O2. The remaining 17 patients received thoracic epidural anesthesia (1% mepivacaine in an 8 ml bolus followed by a continuous infusion of 1% mepivacaine, 3 ml/hr) after endotracheal inturbation, and general anesthesia was maintained with sevoflurane and 50% N2O in O2. End-tidal sevoflurane concentrations were adjusted to maintain mean arterial pressure between 70% and 100% of preinduction values.

Measurements and main results: Venous blood was sampled for measurements of cortisol and catecholamines (epinephrine and norepinephrine) immediately before and 30 minutes after surgical incision. Cortisol levels increased in all three anesthesia techniques. Both catecholamines increased in patients receiving general anesthesia only; catecholamines did not increase significantly in patients receiving general anesthesia combined with epidural anesthesia; in patients receiving general anesthesia supplemented with fentanyl, both catecholamines increased significantly, but the degree of increase in norepinephrine was less than that in the general anesthesia only group.

Conclusions: The fentanyl supplemented group received relatively small doses insufficient to inhibit an increase in catecholamines. Thoracic epidural anesthesia depressed the sympathetic response presumably by blocking afferent sympathetic pathways under the conditions of this study. However, it did not attenuate an increase in cortisol, one of the hypothalamic-pituitary-adrenal stress hormones, during carbon dioxide laparoscopic cholecystectomy in our study. This action may be due to the inability of epidural anesthesia to block phrenic nerves that can convey noxious surgical stimulation to the central nervous system.