Changes in hemodynamics and myocardial metabolism following discontinuation of a dopamine or dobutamine infusion.
Hemodynamics and myocardial metabolism were studied in 20 anesthetized dogs following discontinuation of a dopamine (DA) or dobutamine (DB) infusion. Both groups showed significant decreases in HR, AP, dP/dt, CI, MBFI, and MVO2. Discontinuation of DA decreased lactate extraction, whereas this did not occur with DB. The arteriocoronary venous differences in reduction-oxidation electrical potential (delta Eh) decreased significantly immediately following an abrupt discontinuation of the DA infusion, whereas DB maintained delta Eh at a constant level during and following infusion. Thus, aerobic metabolism was maintained following the discontinuation of DB, and anaerobic metabolism in the myocardium was accelerated immediately following discontinuation of the DA infusion. Although the mechanism that produces the differences observed between DA and DB following discontinuation is not understood, it may result from stimulation of alpha 1-receptors in the myocardium, produced by the residual high level of myocardial tissue norepinephrine (NE) following the termination of DA. A high tissue level of NE combined with a low plasma level of DA may cause an oxygen imbalance of the myocardium, demonstrated by an increase in myocardial oxygen demand and by a reduction in coronary blood flow. It is speculated that this mechanism of oxygen imbalance is a possible explanation for the anaerobic metabolism observed following DA discontinuation.
Tanaka
H
H
Trauma and Critical Care Center, Teikyo University School of Medicine, Tokyo, Japan.
Tajimi
K
K
Nakatani
T
T
Kasai
T
T
Kobayashi
K
K
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects; D004280:Dobutamine / Q000008:administration & dosage / Q000494:pharmacology*; D004285:Dogs; D004298:Dopamine / Q000008:administration & dosage / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D007262:Infusions, Intravenous; D007773:Lactates / Q000097:blood / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000187:drug effects; D011773:Pyruvates / Q000097:blood / Q000378:metabolism; D013318:Stroke Volume / Q000187:drug effects; D013997:Time Factors; D016277:Ventricular Function, Left / Q000187:drug effects
D007773:Lactates; D011773:Pyruvates; D004280:Dobutamine; D010100:Oxygen; D004298:Dopamine