The effect of adenosine and allopurinol on the tolerance of the collapsed lung to warm ischemia.

The collapsed left lungs of dogs were subjected to 1 hour of normothermic ischemia in situ followed by immediate ligation of the contralateral pulmonary artery. Adenosine in a dose of 50 mg/kg prolonged the survival of the dogs significantly. In the survivors only transient changes in the chest x-ray were seen, and no changes in arterial oxygenation were observed. The pulmonary architecture was well preserved on histological studies 14 days after operation. Animals whose ischemic lungs were not protected by adenosine showed an immediate drop in arterial oxygenation and a massive infiltrate of the ischemic lung. Histological study of the lungs showed a complete breakdown of the capillary-alveolar barrier. Allopurinol alone was ineffective by itself and was not able to improve the survival achieved with adenosine further. We conclude that it is possible to prolong the tolerance of a deflated lung to normothermic ischemia by pretreatment with adenosine.