[Myocardial metabolism as affected by propofol in geriatric patients. A comparison with etomidate]

This study was designed to compare the effects of propofol and etomidate on myocardial metabolism in elderly patients without clinical manifestations of heart failure or coronary artery disease. Twenty geriatric patients (age 65-82 years) scheduled to undergo elective major upper-abdominal surgery were studied and randomly allocated to two equal groups (propofol and etomidate). All patients were premedicated with piritramide, 7.5 mg, and promethazine, 25 mg, intramuscularly 1 h before arrival in the anesthesia room. Ten patients received propofol (1.5 mg/kg) for induction of anesthesia, followed by 10-min infusion of an induction dose; thereafter, anesthesia was maintained with a continuous infusion of 0.1 mg/kg per min. Ten patients received etomidate, 18 mg, for induction, followed by 2.4 mg/min for maintenance. Vecuronium was used for neuromuscular blockade. Cardiovascular dynamics were recorded while the patients were awake, 1-2 min after induction during apnoea, and 1, 5 and 30 min after tracheal intubation without surgical stimulation. Coronary blood flow (argon wash-in technique with sampling of blood from the coronary sinus), myocardial oxygen consumption and myocardial uptake of glucose, free fatty acids and lactate were determined in the awake state and 5 and 30 min after intubation. Arterial plasma concentrations of propofol (high-pressure liquid chromatography with fluorescence detection) and etomidate (gas chromatography) were measured every 5 min throughout the investigation period, which lasted 45 min. Overall mean plasma concentrations of propofol were 3.69 +/- 0.16 micrograms/ml and of etomidate 1.1 +/- 0.16 microgram/ml.(ABSTRACT TRUNCATED AT 250 WORDS)