Inotropic therapy for cardiac low output syndrome: comparison of hemodynamic effects of dopamine/dobutamine versus dopamine/dopexamine.

Objective: To examine the effects of a therapy with dopexamine/dopamine in comparison with a regimen of dobutamine/dopamine on the outcome of patients with profound cardiogenic shock.
Material and Methods: Twenty patients presenting with an acute cardiogenic shock assisted with mechanical ventilation, being refractory to a therapy with dopamine alone were analyzed. After persistence of low cardiac output syndrome (cardiac index <2.5 l/min/m2) was confirmed, patients were treated either with receiving dopexamine (2 microg/kg/min) (group 1) or dobutamine (6 microg/kg/min) (group 2) in combination with dopamine (6 microg/kg/min) for 24 hrs. Hemodynamic parameters, urine production and clinical outcome were measured at intervals throughout the study. The groups were similar with respect to demographics and risk factors and there were no significant differences in the supportive treatment and hemodynamics at baseline.
Results: The dopexamine treated patients had lower myocardial oxygen consumption (9310 +/- 2243 mmHg O2/sec vs. 10621 +/- 2552 mmHg O2/sec) and lower mean arterial pressure (66 +/- 11 mmHg vs. 71 +/- 10 mmHg) after the 24 hrs treatment interval, but no one of the changes reached statistical significance. No differences were found between the two groups for other variables and the overall clinical outcome.
Conclusion: The present study revealed that neither substance is superior in the treatment of cardiogenic shock, even if the effect on myocardial consumption and the reported beneficial effects on renal and splanchnic functions might favour the use of dopexamine under certain circumstances.