Influence of Cooling and CO 2 Content of Blood on Bleeding Time. ∗

Abstract

Summary

Employing the dog's hind-leg which permits a controlled study of bleeding time, it has been determined that refrigeration of blood for 10 minutes at 1-2°C causes it to lose its normal hemostatic properties, not recoverable by heating to 37°C. Furthermore violent aeration of blood in air, by liberating CO₂ and driving the pH to the alkaline side, also renders blood non-hemostatic, although by returning the liberated CO₂ to blood, by shaking in atmospheric air containing 9% CO₂, hemostatic action may be recovered. The mechanism of these phenomena, their application as routine methods in the laboratory, and their implication in technics of blood transfusion are discussed.