HEMODYNAMIC ASPECTS OF PULMONARY BRONCHIAL AND LYMPHATIC CIRCULATIONS IN DOG

A method for the extracorporeal perfusion of a pulmonary lobe in both normal and retrograde directions was briefly described. The degree of interchange occurring between the perfused organ and the general circulation was studied using a radioactive intravascular substance (RISA) and a freely diffusible one (tritiated water). The results showed that the mainly intravascular substance injected into the extracorporeal circulation tended to remain in this circuit, no matter which direction the circulation was carried in. Diffusible substances like water, when introduced into the isolated pulmonary circuit, tended to penetrate into the general circulation to some extent, although the amount of leakage was less if the perfusion was carried in the normal direction. All substances injected into the general circulation penetrated in significant amounts into the opposite circuit when the bronchial vessels and lymphatics were left intact. This produced a diluting effect on substances present in the extracorporeal circuit. Toward the end of the perfusion, a state of equilibrium between the exchanges of radioactive substances was reached, although a threshold was constantly maintained between the two circuits. © 1969.