Hemodynamics of Transplanted Lungs

Abstract

Differential bronchospirometry was performed on normal dogs and those with autotransplanted left lungs within two weeks of operation. Left lung blood flow and pulmonary resistance were measured when both lungs were ventilated with oxygen and when the right lung was rendered hypoxic by ventilation with 100 percent nitrogen. Right lung hypoxia caused increased blood flow to both the normal and the transplanted left lung. Both were similarly able to accept this increased flow without significant elevation of pulmonary artery pressure. Absolute resistance of the transplanted lungs was greater than that of the normal lungs (1069 ± 179 versus 567 ± 117 dynes sec cm −5 ). However, when left pulmonary resistance was related to left lung blood flow, the resultant plots from normal and transplanted dogs were indistinguishable. These data indicate that the vasculature of transplanted lungs does not have a fixed resistance and can dilate normally with increased blood flow.