OBSERVATIONS ON INTRAPLEURAL PRESSURE AND ITS INFLUENCE ON THE RELATIVE CIRCULATION RATE IN EMPHYSEMA

Abstract

The peripheral venous pressure is an index to the intrapleural pressure in patients with increased lung volume and in dogs in which distension of the lungs is caused by partially obstructing expiration. It is found that a dye, phenoltetraiodophthalein sodium, injected in a peripheral vein, is retarded in its appearance in a peripheral artery and more dispersed at time of arrival in a markedly emphysematous as compared with a normal subject. The same type of slowing of the circulation of the dye is found in "emphysematous" dogs; however, this delay does not occur when the dye is injected into the right heart and recovered from a peripheral artery. It is suggested that the impediment of the circulation in emphysema does not occur in the lung capillaries as previous investigators have stated, but that the increased intrapleural pressure which constantly accompanies increased lung volume and acts as a dam at the entrance of the blood into the thorax causes a relative peripheral venous stasis.