[Hemodynamic effects of amrinone during emergence from cardiopulmonary bypass]

Amrinone, a phosphodiesterase III inhibitor, is known to exert inotropic and vasodilating effects. This study was undertaken to investigate the hemodynamic effects and optimal dose of amrinone in patients undergoing coronary artery bypass surgery. Seventeen patients with ejection fraction > 0.45 were included. In both group B and C, amrinone 0.5 mg.kg-1 was administered in the venous reservoir near the end of cardiopulmonary bypass (CPB), and doses of 1 and 5 micrograms.kg-1.min-1 by an intravenous infusion. Additional group of A did not receive amrinone. In group B, amrinone increased cardiac index by 79% and stroke index by 81% while decreased mean arterial pressure by 19% and systemic vascular resistance by 59% in comparison with group A. Heart rate did not increase. In group C, changes of hemodynamic variables were almost the same compared with group B. These data suggests that amrinone improves left ventricular performance without increasing myocardial oxygen demand while recovering from CPB. However, a high dose of amrinone should be used in combination with catecholamines because its vasodilating action is potentiated by hyperdynamic state after CPB.