Introduction Shock provokes marked sympathetic activity through hypotensive reflexes and subsequent hypoxia.1-3Both hypoxia and elevated levels of endogenously released sympathetic hormones lead to a severe acidosis characterized by an increase in lactic acid production.4-7In previous animal experiments from this laboratory acidosis has been produced by lactic acid infusion, by hypercapnea, by limiting venous return to that supplied by the azygos and coronary veins, or by rapid intravenous infusions of epinephrine or levarterenol.7,8In all cases acidosis was accompanied by a decrease in ventricular contractile force (VCF) and arterial blood pressure (BP). There was a decrease in the response of the myocardium to injections of test doses of levarterenol. Cardiac output has been observed by others to be significantly decreased during such an addition acidosis.9Conditions which impose a decrease in circulating blood volume have been reported to increase endogenous releases of catechol amines.1,2,5,7