Lung preservation with low-potassium dextran flush in a primate bilateral transplant model.

We used a bilateral lung transplant model to confirm, in primates, the results of lung preservation studies previously obtained in a canine single-lung transplant model. The donor lungs were flushed with low-potassium dextran solution and maintained semiinflated with 100% oxygen at 10 degrees C for a planned ischemic time of 12 hours for the lung implanted first. Of eight experiments performed, results in the 6 operative survivors form the basis of this report. After bilateral lung transplantation, animals were maintained on a ventilator for 6 hours; arterial oxygen tension, pulmonary artery pressure, and pulmonary vascular resistance were determined in the recipients at 2, 4, and 6 hours after transplantation and compared with donor values, which served as controls. Arterial oxygen tension in the recipients did not differ from the controls (p = not significant), whereas the pulmonary artery pressure and pulmonary vascular resistance showed significant elevation (p < 0.05 versus control values). After the 6 hours of assessment, the animals were extubated and 3 survived for 48 to 72 hours with a mean arterial oxygen tension of 69 mm Hg on room air. These results demonstrate excellent lung function after a minimum of 12 hours of preservation in a primate model in which the animal is totally dependent on the function of transplanted lung tissue, and confirm the potential for prolonged clinical lung preservation.