The effects of metabolic acidosis and alkalosis on the response to sympathomimetic drugs in dogs.
Sympathomimetic drugs are commonly used in many circumstances to increase cardiac output, blood pressure, and myocardial contractility. However, factors such as acidosis or alkalosis are known to influence the action of these drugs. This study looked at the response to the administration of epinephrine, norepinephrine, dopamine, dobutamine, isoproterenol, and glucagon at normal pH and under acidotic (pH 7.2 +/- 0.01) and alkalotic (pH 7.59 +/- 0.01) conditions in 17 dogs. Acidosis was produced with an infusion of hydrochloric acid and alkalosis by infusion of sodium bicarbonate. The infusions were given over one hour followed by a 15- to 30-minute stabilization period. With the administration of each sympathomimetic drug at each pH level, hemodynamic parameters and measurements of myocardia; contractility were recorded. Epinephrine increased cardiac output at normal pH, but decreased cardiac output under conditions of both acidosis and alkalosis; the net change from values at pH 7.40 was nearly 3 L/min. The only other drug to demonstrate this reversal of cardiac output, though to a lesser degree, was dopamine, 10 microg/kg/min, and only in the alkalotic state. Dobutamine was the only drug that decreased contractility under acidotic conditions, while all other drugs caused an increase. In sum, epinephrine was the only drug markedly affected by metabolic acidosis and alkalosis. Isoproterenol's hemodynamic effects were altered the least by changes in acid-base balance. Alkalosis had an equally adverse effect on the cardiovascular system as compared with acidosis.
Kaplan
J A
JA
Department of Anesthesiology, The Mount Sinai School of Medicine, New York, NY 10029, USA.
Guffin
A V
AV
Yin
A
A
D000138:Acidosis / Q000503:physiopathology*; D000471:Alkalosis / Q000503:physiopathology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007545:Isoproterenol / Q000494:pharmacology; D013566:Sympathomimetics / Q000494:pharmacology*; D014655:Vascular Resistance / Q000187:drug effects
D013566:Sympathomimetics; D007545:Isoproterenol