Amrinone was used as the sole vasoactive medication in 9 of 14 children (aged 5 months to 8.25 years) given the
drug following open repair of congenital cardiac lesions. Four children received a concomitant
dopamine infusion and one infant had the infusion stopped after 5 hours for low mean arterial pressure (49 mmHg). In the 10 children receiving only
amrinone, cardiac index increased 21% (range, 0 to 94%) after a total loading dose of 4.5 mg/kg given over 1 hour. Four of 14 patients (29%) required
dopamine infusions to maintain mean arterial pressure over 55 mmHg and in these children cardiac index increased from baseline and was maintained during the
amrinone infusion. Preload was held constant by administration of whole blood or
plasmanate during
amrinone loading; a decrease in systemic vascular resistance index was seen resulting in a stable arterial blood pressure. Minimal chronotropic effect was seen and no arrhythmias occurred. The sole child with postoperative
pulmonary hypertension had a beneficial decrease in pulmonary artery pressure, increase in cardiac index, and stable systemic blood pressure during
amrinone use. Cardiac index changes during
amrinone loading in these children were variable and less clearly related to serum levels than reported in adults. Pharmacokinetic analysis in 12 children showed a clearance of 3.4 mL/min/kg, a volume of distribution of 1.65 L/kg, and an elimination half-life of 5.75 hours. Decreases in platelet counts were seen in 6 children and
platelet transfusion was needed in 1; thus, serial platelet counts should be monitored.(ABSTRACT TRUNCATED AT 250 WORDS)