A STUDY OF SPONTANEOUS FULMINANT SHOCK IN A HEART-LUNG-DOG PREPARATION

Abstract

The relative importance of decrease in venous pressure and secondary reduction of cardiac output; primary myocardial impairment, and changes in total peripheral resistance (TPR) in shock was studied by means of a heart-lung-dog prep. Venous flow and cardiac output were under control and TPR could be calculated. In such a prep., a fulminant type of shock developed spontaneously which may resemble clinical types characterized by speedy circulatory failure and death. In 24 such expts. it was shown that shock can develop without progressive reduction or even with a rise of venous pressures or cardiac output and that it cannot be prevented or cured by increasing venous inflow and cardiac output. The fundamental factor responsible for this type of irreversible circulatory failure was a steady and pronounced decrease in total peripheral resistance, which enabled the animal to store, over and above its. own blood vol., quantities of blood equal to 25% of its body \vt. or 4 times its own blood vol. in the mucosa of the upper intestines. Following any prolonged period of hypotension during the development of shock, the cardiac output at equivalent venous pressures also decreased, indicating that depression of the myocardium occurred. In the form of shock studied, it played an important role in the rapid downward trend of blood pressure and was the ultimate cause of death. Adm. of neosynephrine during terminal stages evoked a marked increase in mean arterial pressure and apparent improvement of the myocardium lasting over \ hr. However, the optical pressure pulses had a peaked summit and collapsing character, proving that dynamic improvement cannot be judged by elevation of mean pressure alone. Five dogs primed with liberal doses of cortical adrenal extracts and receiving these extracts during the expts. revealed no indications that the course of dynamic events or the pathological changes in the intestinal mucosa were influenced. It was emphasized, however, that the preps, used perhaps offered too severe a test.