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Circulatory Effects of Denopamine in Newborn Piglets
Author(s) -
Tomita Hideshi,
Coe James Y.,
Olley Peter M.
Publication year - 1992
Publication title -
pediatrics international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.49
H-Index - 63
eISSN - 1442-200X
pISSN - 1328-8067
DOI - 10.1111/j.1442-200x.1992.tb00977.x
Subject(s) - medicine , circulatory system , emergency medicine , anesthesia , intensive care medicine , cardiology
Denopamine is an orally active β 1 agonist whose cardiovascular action in the newborn is unknown. We evaluated its circulatory effects during normoxia in newborn piglets less than 7 days of age. The piglets were acutely instrumented under general anesthesia with an electromagnetic flow probe around the main pulmonary artery and catheters in the main pulmonary artery, aorta, left ventricle, and the right and left atria. A Millar high‐fidelity catheter was used to measure left ventricular dp/dt. The ductus arteriosus was ligated. Denopamine was administered in the right atrium as a continuous infusion of 2, 4, and 8μg/kg per min for 10 min each. Although cardiac index, heart rate and left ventricular dp/dt increased dose‐dependently by 46.0 ± 18.2%, 87.1 ± 34.9% and 159.9 ± 42.4%, respectively, stroke index was not significantly altered. Unlike pulmonary artery pressure (which increased dose‐dependently), aortic pressure increased with 2 and 4μg/kg per min denopamine, respectively, it fell with 8μg/kg per min denopamine. Similarly, the systemic vascular resistance decreased with the high dose (8 μg/kg per min). There was no significant change in pulmonary vascular resistance. Denopamine is potently inotropic in the adult. However, its circulatory effect in the neonate is dependent on its chronotropic action. Furthermore, denopamine is a systemic vasodilator at high doses in the neonatal circulation.