Comparison of Hemodynamic and Hormonal Effects of Large Single-Dose Fentanyl Anesthesia and Halothane/Nitrous Oxide Anesthesia for Coronary Artery Surgery

Abstract

This study was conducted to compare our standard halothane/N₂O anesthetic technique with large single-dose fentanyl (150 μg/kg)/O₂ anesthesia in patients undergoing coronary artery surgery. We chose to look at two discrete stimuli (tracheal intubation and sternotomy) and measured changes in mean arterial pressure, heart rate, mean pulmonary artery occluded pressure, PAO cardiac output, derived indices (stroke volume, rate-pressure product, systemic vascular resistance, and changes in the plasma concentrations of growth hormone, epinephrine, norepi-nephrine, and renin activity. Both groups of patients were comparable in age, height, weight, and surface area. Variance in hemodynamic functions did not reach undesirable levels in either group. In the patients given fentanyl, there was a significant increase in heart rate after pancuronium administration. Mean arterial pressure and mean pulmonary artery occluded pressure did not change significantly from control values in either group; however, there was enough divergence between groups for the changes to be statistically significant. Cardiac output decreased in both groups after sternotomy. There was no significant change in systemic vascular resistance in either group. The only significant hormonal change was a significant increase in plasma levels of growth hormone in patients who received halothane/N₂O for anesthesia (p < 0.001). Plasma fentanyl concentrations decreased rapidly after bolus administration consistent with pharmacokinetics previously described. Of the 10 patients given fentanyl two were aware during sternotomy; of the 12 patients in the halothane group none had awareness. We believe that large-dose fentanyl offered better preservation of coronary perfusion and more attenuation of the hormonal flux observed with stress than halothane/N₂O anesthesia. Large-dose fentanyl may offer more advantages in patients with greater ventricular impairment.