Hemodynamic and Renal Effects of Dopexamine and Dobutamine in Patients With Reduced Cardiac Output Following Coronary Artery Bypass Grafting

Dopexamine hydrochloride is a novel synthetic adrenergic agonist that combines the renal effects of dopamine with the hemodynamic effects of dobutatmine. Our study is designed to compare the hemodynamic, diuretic, and natriuretic effects of dopexamine and dobutamine in patients with reduced cardiac index following heart surgery. Prospectively randomized, blinded study. Operating room and intensive care unit of a large, urban, academic medical center. Twenty-eight patients undergoing elective coronary artery bypass grafting (CABG) with preoperative ejection fraction of at least 40 percent gave informed consent. The study group consisted of the ten patients who had a cardiac index ≤2.5 L/min/m2 (while receiving no inotropic medication) immediately after separation from cardiopulmonary bypass. Study patients were randomly given a starting dose of either 5μg/kg/min of dobutamine (n=5) or 2 μg/kg/min of dopexamine (n=5). During the initial 30 min following separation from bypass, dosages were titrated incrementally to maintain cardiac index ≥3.0/L/min/m2. Further titrations of the drug were done only if cardiac index fell below 3.0 L/min/m2 or if sustained tachycardia occurred during the 24-h study period. Data were collected at 5- and 10-min intervals for the first 30 min after separation from bypass, hourly for the next 8 h, then every 2 h for the remainder of the study period. Both drugs increased cardiac index by more than 50 percent over baseline (dobutamine 2.2 ± 0.1 to 3.5 ± 0.2 [p