Comparison of the Effects of 15 and 60 ,ug/kg Fentanyl Used for Induction of Anesthesia in Patients with Coronary Artery Disease

Abstract

We compared the effects of 15 and 60 [mu]g/kg fentanyl used for induction in 40 patients, 50-72 yr old, with coronary artery disease and mildly impaired ventricular contractility. Morphine (0.1 mg/kg) and scopolamine (0.4 mg) were used for premedication. Crystalloid (500 ml) was administered before induction, and nitroglycerin (0.3 [mu]g kg 1-min1) was infused during the study. Fentanyl, 15 or 60 [mu]g/kg, was administered at a rate of 1.2 [mu]g kg-1-sec 1. Pancuronium (0.04 mg/kg) and metocurine (0.16 mg/kg) were used for muscle relaxation. Data were collected 2 min before induction (baseline), before intubation (3 min), at 6 min, and at 13 min. Responses to 15 and 60 [mu]g/kg were similar. At 3 min the heart rate (HR) in patients given 15 [mu]/kg increased by 6; whereas the HR in those given 60 [mu]g/kg increased by 14 (P < 0.01). Subsequent differences in HR were not significant. There were no dose-related differences in mean arterial pressure, cardiac index, central venous pressure, or pulmonary capillary wedge pressure. The EEG showed high-voltage low-frequency activity within 2 min in all patients. Arterial plasma fentanyl concentrations at 3 min averaged 25.9 +/- 3.8 ng/ml with 15 [mu]g/kg and 89.9 +/- 15.2 ng/ml with 60 [mu]/kg. At 4 hr, plasma concentrations averaged 0.4 +/- 0.2 ng/ml and 3.6 +/- 0.7 ng/ml, respectively. We conclude that anesthesia for induction and intubation is achieved by the rapid administration of 15 [mu]g/kg fentanyl and that 60 [mu]g/kg has no substantially different effect on cardiovascular responses.