Comparative hemodynamic effects of isoproterenol, dopamine, and dobutamine in the newborn dog

To compare the hemodynamic effects of isoproterenol, dopamine, and dobutamine in the immature animal, each drug was infused into anesthetized open chest puppies and cardiac output was measured, as were systemic arterial blood pressure, heart rate, and renal artery blood flow. Cardiac output was increased by dopamine and dobutamine. Isoproterenol caused a significantly greater increment of heart rate than either of the other agents to achieve a similar change of cardiac output. Systemic arterial mean blood pressure was increased by dopamine and dobutamine, but decreased by isoproterenol. Dopamine produced a significant increase of renal artery blood flow while renal artery blood flow was unchanged by dobutamine and decreased by isoproterenol.