Bronchial healing, lung parenchymal histology, and blood gases one month after transplantation of lungs topically cooled for 2 hours in the non-heart-beating cadaver

BACKGROUND: The aim of this study was to investigate, in an experimental survival model, the functional and morphologic results of lung transplantation using lungs from non-heart-beating donors. METHODS: Left lungs, topically cooled to 25 degrees C for 2 hours in situ after 5 minutes of circulatory arrest followed by 26 minutes of unsuccessful cardiopulmonary resuscitation, were transplanted into syngeneic rats. Five weeks after the transplantation, right pneumonectomy was performed and blood gases measured after 60 minutes. In a control group, fresh donor lungs were used for transplantation and comparison was made with the cadaver group and a group of normal rats after right pneumonectomy. Morphologic changes were evaluated by semiquantitative scoring of 13 different parameters to obtain a total histologic index for each rat. RESULTS: Computerized tomography scans of the chest made during the third post-operative week showed normal lung parenchyma in both groups, and at 5 weeks there were no significant differences in blood gases. The bronchial anastomoses showed normal healing in all cases. The histologic changes in the lung parenchyma were generally mild and focal, primarily consisting of interstitial and perivascular mononuclear inflammation, bronchial inflammation and athelectasis. Surprisingly, the transplanted controls demonstrated the most pronounced changes, although only the difference in total histologic index between groups was significant. CONCLUSIONS: Lungs from non-heart-beating donors, topically cooled in the cadaver for two hours after failed resuscitation, showed normal bronchial healing and favorable parenchymal histology compared to transplanted control lungs 5 weeks after transplantation.