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Hemodynamic effects of amrinone and colloid administration in children following cardiac surgery
A M Lynn1, G K Sorensen, G D Williams
1Department of Anesthesiology, School of Medicine, University of Washington, Seattle.
Insights
Amrinone effectively increased cardiac index in children after heart surgery, with minimal side effects. Monitoring platelet counts is recommended due to observed decreases.
Area of Science:
- Pediatric Cardiology
- Cardiovascular Pharmacology
- Pediatric Critical Care
Background:
- Congenital cardiac lesions often require surgical repair.
- Postoperative hemodynamic support is crucial in pediatric cardiac surgery.
- Amrinone is a phosphodiesterase inhibitor with inotropic and vasodilatory properties.
Purpose of the Study:
- To evaluate the efficacy and safety of amrinone as a vasoactive medication in children following open repair of congenital cardiac lesions.
- To assess the hemodynamic effects of amrinone, including changes in cardiac index and blood pressure.
- To determine the pharmacokinetic profile of amrinone in pediatric patients.
Main Methods:
- Retrospective analysis of 14 children (5 months to 8.25 years) receiving amrinone post-cardiac surgery.
- Hemodynamic parameters (cardiac index, mean arterial pressure) were monitored.
- Pharmacokinetic analysis was performed in 12 children.
Main Results:
- Amrinone administration led to a 21% increase in cardiac index in children receiving it as the sole vasoactive agent.
- Systemic vascular resistance index decreased, maintaining stable arterial blood pressure.
- No significant arrhythmias were observed; one child with pulmonary hypertension showed improvement.
Conclusions:
- Amrinone demonstrates efficacy in improving cardiac output in pediatric patients post-cardiac surgery.
- Its vasodilatory effect helps maintain blood pressure, and it may benefit those with pulmonary hypertension.
- Monitoring of platelet counts is essential due to potential decreases.
Abstract:
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)