Acidosis, Catecholamines And Cardiovascular Dynamics

Abstract

Experimental studies were performed in dogs on the effect of respiratory and metabolic acidosis on cardiac output and peripheral and pulmonary resistance and on the response to epinephrine during acidosis. Metabolic acidosis produced: no depression in cardiac output until the pH fell below 6.9; no significant change in arterial pressure or peripheral vascular resistance; a progressive increase in pulmonary arterial pressure and resistance; retained responsiveness to epinephrine down to pH 6.8, and an abrupt and severe deterioration at pH 6.6-6.4. Respiratory acidosis produced: a progressive increase in cardiac output down to pH 6.8; no change in arterial pressure and a decrease in peripheral vascular resistance; an increase in pulmonary artery pressure but not in resistance, and a retained responsiveness to epinephrine down to pH 6.8. No adverse effect on the cardiovascular dynamics studied was produced by either respiratory or metabolic acidosis unless the pH fell below 6.9 and that essentially normal responsiveness to catecholamines was present throughout the same range of acidosis.