Comparative hemodynamic effects of dopamine and dobutamine in patients with acute cardiogenic circulatory collapse.

The hemodynamic effects of dopamine (DPM) and dobutamine (DBM) were compared in 13 patients with acute cardiogenic circulatory collapse. All patients presented with acute pump failure and inadequate systemic perfusion, and most were hypotensive. Nine patients had an acute myocardial infarction (AMI); the other four patients had an acute decompensation of a previously stable ischemic cardiomyopathy, and presented with a low-output syndrome in the absence of documented AMI. Patients were studied with a randomized single crossover design using each patient as his own control. Both drugs were given at doses of 2.5, 5, and 10 micrograms/kg/min for periods of 10 minutes at each dose while hemodynamics were monitored. No other vasoactive drugs were used during the study. Because of advanced age or severe peripheral vascular disease, no patient was considered suitable for intra-aortic balloon counterpulsation. There were no significant differences between the two drugs with regard to heart rate, mean-arterial pressure, systemic vascular resistance, stroke work index, or mean right atrial pressure. DBM improved stroke index and cardiac index significantly (p less than 0.05) more than DPM at doses of 5 micrograms/kg/min. DPM increased left ventricular filling pressure (LVFP) more than DMB at 5 micrograms/kg/min (p less than 0.001) and at 10 micrograms/kg/min (p less than 0.05). Although both DPM and DBM are useful in acute cardiogenic circulatory collapse, there appear to be important differences in their effect on LVFP and in the mechanisms whereby they increase blood pressure.