Identification of optimal conditions for lung graft storage with Euro-Collins solution by use of a rat orthotopic lung transplant model

Background-Lung preservation disrupts normal vascular homeostasis, resultin g in increased permeability. vasoconstriction, and endothelial cell adhesio n for neutrophils. We hypothesized that a storage strategy that best preser ves post-lung transplantation (LTX) vascular homeostasis might be organ and species specific. Because of the potential utility of a rat LTX model for developing improved lung preservation strategies, we have attempted to iden tify the optimal physical conditions for rat lung graft storage. Methods and Results-Conditions that were tested included harvest inflation pressure (0, 10, or 20 mm Hg), inflation gas composition (100% N-2, room ai r, or 100% O-2), and storage temperature (4 degrees, 10 degrees, or 15 degr ees C). Modified Euro-Collins solution served as the base preservation solu tion for ail experiments, with a preservation duration of 4 to 6 hours. Art erial oxygenation (PaO2, mm Hg), pulmonary vascular resistance (mm Hg/mL pe r minute), recipient survival (%), and graft neutrophil infiltration (Delta Abs(460) (nm)/min) were measured 30 minutes after transplantation of the l eft lung and exclusion of the right lung from the circulation. All tested c onditions significantly affect post-LTX vascular homeostasis. Inflation at 10 mm HE pressure preserved lungs significantly better than did other press ures. There was a tendency for room air to improve all measured variables c ompared with 100% N-2 or 100% O-2 and a significant improvement in recipien t survival with room air storage. Of the 3 storage temperatures investigate d, 10 degrees C storage provided the best preservation in terms of PaO2, gr aft neutrophil infiltration, and survival. Conclusions-We conclude that storage at 10 degrees C, 10 mm Hg inflation pr essure, with room air establishes optimal lung storage conditions with Euro -Collins solution in this rat LTX model. These data suggest that these cond itions should be used to evaluate new and potentially improved preservation strategies.