Comparative circulatory effects of isoproterenol, dopamine, and dobutamine in conscious lambs with and without aortopulmonary left-to-right shunts.

Abstract

We studied the effect on the circulation of the catecholamines isoproterenol, dopamine, and dobutamine in chronically instrumented lambs with aortopulmonary left-to-right shunts (ages 11 to 87 days) and without shunts (ages 8 to 97 days). Infusion of 0.1 ,ug/kg/min isoproterenol or 10 gvg/kg/min dobutamine markedly increased heart rate and systemic and pulmonary blood flows, while stroke volume and the left-to-right shunt flow did not change. Since 1222of myocardial performance: contractility, preload, and afterload.4 Moreover, isolated heart preparations have shown that the inotropic response to dopamine in perfused ventricles increased with advancing age in contrast to the response to isoproterenol, which was equal at all ages.5' ' Not only these age-related differences but also the different response of newborn and adult vessels to adrenergic stimuli7 suggest that different catecholamines should be used in children and adults. Therefore we infused dobutamine, dopamine, and isoproterenol into conscious lambs with and without aortopulmonary left-to-right shunts. Little is known about the hemodynamic effects of catecholamines in the presence of a left-to-right shunt lesion8 despite the fact that these lesions are the most common of all congenital heart diseases and often result in circulatory congestion, for which proper treatment should be instituted.The objectives of this study were to compare the hemodynamic changes caused by the infusion of dopamine, dobutamine, and isoproterenol into conscious lambs with and without aortopulmonary left-to-right shunts to establish differences in changes between the

Cardiopulmonary effects of dobutamine and norepinephrine infusion in healthy anesthetized alpacas

“…The β 1 -adrenergic receptor stimulation caused by dobutamine similarly increases the HRs of foals, 10,13 ponies, 16 horses, 15,17,18 and lambs. 19 The ability of dobutamine to induce a clinically important HR increase at low and high infusion rates suggests that the lowest possible dose should be administered to avoid potential arrhythmogenesis. Administration of 8 µg of dobutamine/kg/ min resulted in transient atrial premature contractions in 1 of 8 alpacas, which resolved upon discontinuation of the infusion.…”

“…Dobutamine, an inotropic agent with predominant effects on β 1 -and β 2 -receptors and minor α 1 -adrenergic receptor effects, is indicated to increase CO and is often used to enhance tissue Do 2 during general anesthesia and in critically ill patients. 8 Dobutamine increases MAP and CI in foals, 10,13,14 horses, [15][16][17][18] lambs, 19 and sheep. 20,21 Norepinephrine primarily acts as a vasopressor with α 1 -, α 2 -, and β 1 -adrenergic receptor activity 8 and is principally indicated for treatment of vasodilatory shock to maintain organ perfusion.…”