Tissue Damage Of Non-Heart-Beating Donor Lungs After Long-Term Preservation: Evaluation of Histologic Alteration, Bronchoalveolar Lavage, and Energy Metabolism

Several studies have shown that warm ischemia before short-term preservation of pulmonary grafts from non-heart-beating donors (NHBD) induced morphological changes, but still provided a good pulmonary graft function. The aim of this study was to investigate morphological and metabolic changes of NHBD lungs after long-term preservation. Left lung allotransplantation was performed on 12 native-bred pigs. In the NHBD group, lungs were subjected to 90 min of warm ischemia before harvesting, whereas lungs in the HBD group were harvested immediately after cardiac arrest. After a total ischemic period of 19 h, lungs were reperfused and pulmonary gas exchange was assessed. Bronchoalveolar lavage (BAL) and tissue specimen for wet-to-dry weight (W/D) ratio, histologic examination, and measurement of high-energy phosphates were taken 5 h after reperfusion. All parameters were compared with a sham-operated control group. Five hours after reperfusion, mean paO2 and paCO2 were 288 ± 52 and 48 ± 0.8 mmHg, respectively, during isolated ventilation of the pulmonary graft with 100% oxygen in the NHBD group. W/D ratio and high-energy phosphates of the pulmonary graft did not differ between our study groups. Histologic examination showed significant morphological changes in the HBD and NHBD group, but alterations were more pronounced in the NHBD group. The percentage of neutrophils, total protein content, and potassium concentration were significantly elevated in the BAL fluid of the NHBD group. Despite the observed aggravation of cellular injury after long-term preservation, NHBD lungs still performed a good pulmonary graft function.