[Hemodynamic effects of amrinone on patients with moderate and severe cardiac dysfunction after open heart surgery]

Hemodynamic effects of amrinone and the changes in pulmonary shunt were studied in patients for open heart surgery. Eighteen patients were allocated into two groups (group L, H) on the first day of surgery. Group L consisted of 10 patients who received moderate-dose catecholamine (DOA + DOB < 12 micrograms.kg-1.min-1) and group H consisted of 8 patients who needed high-dose catecholamine (DOA + DOB > or = 12 micrograms.kg-1.min-1) to maintain normal hemodynamics. After baseline measurement, amrinone infusion was started and the dose was increased by every 2 hours (5, 10, 20 micrograms.kg-1.min-1). At dose of 20 micrograms.kg-1.min-1, cardiac index increased significantly in group L but not in group H. SVRI and PVRI decreased by dose related fashion in both groups. Systemic arterial pressure was unaltered in group L while it decreased significantly in group H. PaO2 decreased and pulmonary shunt increased in both groups. These results suggest that inotropic response of amrinone depends on the basal level of myocardial contractility although vasodilative property and the effect on the pulmonary shunt are almost similar in both groups.