Myocardial Metabolic and Hemodynamic Changes During Propofol Anesthesia for Cardiac Surgery in Patients with Reduced Ventricular Function

Abstract

This study examined the hypothesis that the use of propofol for induction and maintenance of anesthesia in patients with reduced ejection fraction (< 0.5) undergoing coronary artery revascularization would not be associated with a greater degree or incidence of myocardial ischemia as compared to patients receiving a moderate dose sufentanil-enflurane anesthetic technique. Two groups of patients were assigned randomly to receive one of two propofol anesthetic regimes. Group A (n = 21) received propofol 1-2 mg/kg as the induction drug and sufentanil 0.03 micrograms.kg-1.min-1 (fixed rate) plus propofol 50-200 micrograms.kg-1.min-1 (variable rate) infusions for maintenance of anesthesia. Group B (n = 21) received sufentanil 5 micrograms/kg for induction and propofol 50-200 micrograms.kg-1.min-1 (variable rate) infusion for maintenance of anesthesia. For comparison, a third group (Group C, n = 18) was studied subsequently. This group received sufentanil 5 micrograms/kg for induction of anesthesia which was maintained with enflurane. Adverse hemodynamic changes (hypertension, tachycardia) were managed by additional propofol (Groups A and B), sufentanil (Group C), or vasopressors (hypotension). Hemodynamic and myocardial metabolic profiles were measured when awake and sedated and at postinduction, postintubation, postincision, poststernotomy, and precardiopulmonary bypass times. Ischemia was assessed by measuring myocardial lactate production. The incidence of myocardial lactate production was reduced in Group B as compared to Group C (Group A, 45/126; Group B, 23/126; Group C, 58/107; P < 0.05). Myocardial lactate flux declined in all groups as surgery progressed; but apart from the reduction in flux (indicative of increased ischemia) noted in Group C versus Group B postinduction, no between-group differences were detected.(ABSTRACT TRUNCATED AT 250 WORDS)