Effect of acidity on blood coagulation

Abstract

Various methods were used to determine the effect of decreasing the pH on the coagulation of whole blood. It was found that injection of lactic acid into the slowly moving blood of an A-V shunt caused death in dogs much faster than the same rate of acid injection into the fast-moving blood of the aorta. Also, it was found that lowering the pH of withdrawn heparinized blood made it toxic upon reinjection, whereas blood withdrawn and not treated, treated with the neutralized acid-base mixture, or to which a larger amount of heparin had been added was not toxic upon reinjection. Heparinized blood withdrawn from a dog and to which various amounts of lactic acid were added showed a decrease in its clotting time as the pH became lower and lower. Below a pH of approximately 6.7, the heparinized blood coagulated almost as rapidly as nonheparinized blood. Finally, it was found that there was clotting in ligated vascular tubes of dogs after lowering the pH of the blood, whereas no clotting occurred in vascular tubes ligated before the acid was given or after the pH of the dog blood had returned to normal. Emphasis is placed on the fact that the decrease in pH in dogs subjected to circulatory arrest is associated with intravascular clotting.