Dopamine may preserve the myocardial oxygen balance better than dobutamine when administered with milrinone.
OBJECTIVE
To compare the hemodynamic effects of dopamine with those of dobutamine when administered with milrinone in patients undergoing non-cardiac surgery.


METHODS
In 14 patients undergoing major surgery during anesthesia with isoflurane, milrinone (50 microgram*kg(-1) followed by 0.25 microgram*kg(-1)*min(-1)) was administered. Hemodynamic baseline values were assessed 50 min after continuous infusion of milrinone. Additional infusion of either dopamine or dobutamine, randomly selected, was started at the rate of 4 and later 8 microgram*kg(-1)*min(-1); each hemodynamic variable was measured 20 min after changing the infusion rate. One hour after ceasing the infusion of one catecholamine (dopamine or dobutamine), the other was infused at the rate of 4 and 8 microgram*kg(-1)*min(-1).


RESULTS
Milrinone increased heart rate (HR), but decreased mean arterial pressure (MAP) and systemic vascular resistance (SVR) (P < 0.05 for each). Dopamine administered with milrinone significantly increased MAP and cardiac output (CO), whereas dobutamine significantly increased HR and CO, but decreased SVR. By comparison between dopamine and dobutamine administered at the rate of 8 microgram*kg(-1)*min(-1), there was a significant difference in HR, MAP, and SVR (P < 0.01, 0.01, and 0.05, respectively).


CONCLUSIONS
Dopamine and dobutamine administered with milrinone induce different hemodynamic changes: dopamine increases MAP without affecting HR, whereas dobutamine increases HR. Our data suggest that the myocardial oxygen balance might be better preserved with dopamine than with dobutamine when administered with milrinone.
Takamatsu
Isao
I
Department of Anesthesiology, National Defense Medical College, Tokorozawa, Saitama, Japan.
Karasawa
Fujio
F
Okuda
Tomohiro
T
D000368:Aged; D002316:Cardiotonic Agents / Q000494:pharmacology*; D004280:Dobutamine / Q000494:pharmacology*; D004298:Dopamine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D020105:Milrinone / Q000494:pharmacology*; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects*
D002316:Cardiotonic Agents; D004280:Dobutamine; D020105:Milrinone; D004298:Dopamine