Viability of canine lung after temporary ischemia under cooling. An electron microscopy study

To evaluate the viability of the lung for transplantation, we observed in dogs the ultrastructural alterations after temporary ischemia with cooling and after subsequent reestablishment of ventilation and pulmonary circulation. Initial alterations were vacuolization and condensation in the alveolar lining of the epithelial cells. At this stage, gross lung edema did not occur after the subsequent reestablishment of ventilation and pulmonary circulation. According to the prolongation of the ischemia, edematous changes extended over the alveolar structure. In cases of gross lung edema after the reestablishment of pulmonary circulation, alterations such as swollen endothelial cytoplasm and coarse interstitium appeared in the lung before recirculation, in addition to changes in the pneumocytes. Our observations clearly show the importance of changes in the endothelium as a cause of gross lung edema, hence such should be considered when evaluating the viability of a donor lung.