HYPERINFLATION OF CANINE LUNG ALLOGRAFTS DURING STORAGE INCREASES REPERFUSION PULMONARY-EDEMA

The optimal state of inflation for lung allografts during preservation is not known. We previously showed that hyperinflation of canine lung allografts during storage improved posttransplant graft function as m easured during 10 minutes of contralateral pulmonary artery occlusion. However, we have also shown that hyperinflation during storage increa ses pulmonary capillary permeability, It is possible that short-term t otal cardiac perfusion through the transplanted left lung (for assessm ent) may not adequately reproduce the clinical situation. The purpose of this study was to assess the effects of hyperinflation during stora ge in a canine left single-lung transplantation model in which all per fusion was continuously directed to the graft after implantation, Twen ty canine left single-lung transplants were done, The lungs of donor a nimals were ventilated at a tidal volume of 750 ml and an inspired oxy gen fraction of 100%., Donor lungs were flushed with modified Euro-Col lins solution and the trachea occluded at end inspiration. For donors in groups I and III, the trachea was sealed at that postinflation volu me, In groups Il and IV, 200 cc of air was withdrawn from the endotrac heal tube under positive pressure and the trachea sealed at the lower tidal, volume. Lungs were then extracted and stored at 1 degrees C for 12 hours, After the preservation period, left lung transplants were p erformed, After implantation in all groups, the right pulmonary artery was ligated, In groups I and II, the right bronchus was ligated and i n groups III and IV the right bronchus was kept open, Subsequent allog raft gas exchange and hemodynamics were assessed during a 6-hour perio d of reperfusion. After assessment, both lungs were excised, wet/dry l ung weight ratio was calculated, and histologic examination was done, During the 6-hour assessment, lungs stored in a state of hyperinflatio n (groups I and III) showed rapid deterioration of gas exchange. At th e final assessment, arterial oxygen tension and alveolar-arterial oxyg en gradient of groups I and III were significantly worse than those of groups II and IV (group I versus group II: arterial oxygen tension 87 .5 +/- 15.0 versus 373.8 +/- 65.5 mm Hg, alveolar-arterial oxygen grad ient 564.4 +/- 13.2 versus 298.6 +/- 69.3 tnm Hg, p < 0.053 group III versus group IV: arterial oxygen tension 245.6 +/- 33.0 versus 543.6 /- 41.8 mm Hg, alveolar-arterial oxygen gradient 392.5 +/- 35.6 versus 120.5 +/- 34.7 mm Hg, p < 0.01), We conclude that donor lung hyperinf lation during storage does not provide better posttransplant allograft function when perfusion is limited only to the allograft.