Hemodynamic and renal effects of dopexamine and dobutamine in patients with reduced cardiac output following coronary artery bypass grafting.
OBJECTIVE
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.


METHODS
Prospectively randomized, blinded study.


METHODS
Operating room and intensive care unit of a large, urban, academic medical center.


METHODS
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 < or = 2.5 L/min/m2 (while receiving no inotropic medication) immediately after separation from cardiopulmonary bypass.


METHODS
Study patients were randomly given a starting dose of either 5 micrograms/kg/min of dobutamine (n = 5) or 2 micrograms/kg/min of dopexamine (n = 5). During the initial 30 min following separation from bypass, dosages were titrated incrementally to maintain cardiac index > or = 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.


RESULTS
Both drugs increased cardiac index by more than 50 percent over baseline (dobutamine 2.2 +/- 0.1 to 3.5 +/- 0.2 [p < 0.05]; dopexamine, 2.3 +/- 0.1 to 3.5 +/- 0.1 [p < 0.05] L/min/m2). The mean dose required to maintain cardiac index > or = 3.0L/min/m2 was 1.5 micrograms/kg/min for dopexamine and 3.5 micrograms/kg/min for dobutamine. There were no significant differences in either urinary output or net sodium excretion in the dopexamine group compared with the dobutamine group, and tachycardia (heart rate > 120 beats/min) was more common in the dopexamine group.


CONCLUSIONS
Our study demonstrates that dopexamine produces hemodynamic, diuretic, and natriuretic effects similar to dobutamine in patients with reduced cardiac index following CABG.
MacGregor
D A
DA
Department of Anesthesia, Wake Forest University, Winston-Salem, NC 27157.
Butterworth
J F
JF
Zaloga
C P
CP
Prielipp
R C
RC
James
R
R
Royster
R L
RL
D000319:Adrenergic beta-Antagonists / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D000368:Aged; D002303:Cardiac Output, Low / Q000188:drug therapy* / Q000453:epidemiology / Q000503:physiopathology; D001026:Coronary Artery Bypass; D004231:Diuresis / Q000187:drug effects; D004280:Dobutamine / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D004298:Dopamine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D015259:Dopamine Agents / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D004311:Double-Blind Method; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007668:Kidney / Q000187:drug effects* / Q000503:physiopathology; D008875:Middle Aged; D009318:Natriuresis / Q000187:drug effects; D011183:Postoperative Complications / Q000188:drug therapy* / Q000453:epidemiology / Q000503:physiopathology; D011446:Prospective Studies; D013223:Statistics as Topic
D000319:Adrenergic beta-Antagonists; D015259:Dopamine Agents; C046318:dopexamine; D004280:Dobutamine; D004298:Dopamine