STUDIES OF RIGHT AND LEFT VENTRICULAR ACTIVITY DURING HEMORRHAGIC HYPOTENSION AND SHOCK

Publisher Website
Google Scholar
Abstract
Right and left ventricular activities were studied by 2 methods in an effort to evaluate cardiodynamic factors involved in the progressive circulatory failure characteristic of hemor-rhagic shock. The first method consisted of recording right ventricular pressure curves in naturally breathing, anesthetized dogs optically by aid of a sound introduced into the right ventricle via a jugular vein. Left ventricular activity was inferred from aortic pressure curves. Successive right ventricular pressure curves recorded during hemorrhage and hypotension showed a more gradual rise, earlier summits and an abbreviation of the systolic ejection phase. Initial tension fell during hemorrhage, but increased during the latter part of the hypotensive period. Following reinfusion of all withdrawn blood and right ventricular pressure curves were restored to normal amplitude, slope and duration. During the period of progressive circulatory failure the transformation of the pressure curves resembled that seen during hemorrhage and hypotension. Shortening of systole occurred in the right ventricle as well as in the left ventricle as indicated by the aortic pressure curves both during hemorrhage and post-infusion failure. Such abridgement of systole was independent of heart cycle length and strongly suggests myocardial failure. A more critical evaluation of initial tension changes was made by recording right and left ventricular pressure directly in open-chest dogs by means of cannulae passed through the myocardium into the ventricular chambers. This method avoided the effects of changing intrathoracic pressure. The results of these expts. confirm and extend the observations of the previous series. A small rise of right ventricular initial tension and a slightly greater rise of left ventricular initial tension in the late stages of shock does not appear to be significant when considered in conjunction with data on cardiac output and systolic discharge from comparable expts. The question of whether initial tensions are reliable indices of diastolic stretch, and whether other determinants of myocardial response must be recognized is discussed.

This publication has 4 references indexed in Scilit: