Comparison of dopamine and dobutamine following coronary artery bypass grafting

A prospective, randomized comparison of the hemodynamic effects of dopamine and dobutamine was performed in 20 patients following coronary artery bypass grafting. Approximately 6 hours postoperatively, when patients were hemodynamically stable, either dopamine or dobutamine was administered at 2.5, 5.0, and 7.5 micrograms per kilogram of body weight per minute. At 5.0 micrograms/kg, both drugs increased cardiac index without changing heart rate, mean arterial pressure, pulmonary capillary wedge pressure, or peripheral vascular resistance. At 7.5 microgram/kg, dobutamine caused a further increase in cardiac index without changing the other variables. In contrast, increasing dopamine from 5.0 to 7.5 micrograms/kg/min caused significant increases in mean arterial pressure, pulmonary capillary wedge pressure, and pulmonary vascular resistance but no further increase in cardiac index. We conclude that dobutamine is preferable to dopamine in patients following coronary artery bypass grafting, since it produces consistent, dose-related increases in cardiac index without increases in heart rate, mean arterial pressure, pulmonary capillary wedge pressure, or pulmonary vascular resistance.