Comparison of the hemodynamic effects of amrinone in patients who required low-to-moderate-dose and high-dose catecholamines after cardiac valve replacement.

Abstract

To determine hemodynamic response to amrinone in patients after cardiac surgery, in relation to the postoperative cardiac function, which was indicated by the required doses of catecholamines. Prospective clinical study. Surgical intensive care unit in a university hospital. Fourteen patients who required a low-to-moderate dose of dopamine and dobutamine (group L) and 14 patients who required a high dose of dopamine and dobutamine (group H) after cardiac valve replacement. A loading dose of amrinone (0.75 mg/kg) was administered during a 15-min period and the continuous infusion was followed incrementally by doses of 5, 10, and 20 microg/kg/min every 60 mins on the first postoperative day. Hemodynamic variables were determined by the radial and pulmonary artery catheters at a dose of 0, 5, 10, and 20 microg/kg/min. Two-way repeated-measures analysis of variance showed significant interaction in the two groups in cardiac index and mean systemic arterial pressure. Cardiac index increased in a dose-dependent manner in group L but was unchanged in group H. Systemic vascular resistance index decreased in a dose-dependent manner in both groups. The mean systemic arterial pressure decreased in group L at a dose of 5 microg/kg/min and returned to the baseline level at doses of 10 and 20 microg/kg/min. On the other hand, the mean systemic arterial pressure significantly decreased in group H at a dose of 20 microg/kg/min. The inotropic effects of amrinone after cardiac valve replacement may be associated with the postoperative myocardial reserve, which was indicated by the required doses of catecholamines, although a similar vasodilative effect was observed in both groups.