Identification of Optimal Conditions for Lung Graft Storage With Euro-Collins Solution by Use of a Rat Orthotopic Lung Transplant Model

Abstract

Background —Lung preservation disrupts normal vascular homeostasis, resulting in increased permeability, vasoconstriction, and endothelial cell adhesion for neutrophils. We hypothesized that a storage strategy that best preserves 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 identify 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 air, or 100% O 2 ), and storage temperature (4°, 10°, or 15°C). Modified Euro-Collins solution served as the base preservation solution for all experiments, with a preservation duration of 4 to 6 hours. Arterial oxygenation (Pa o 2 , mm Hg), pulmonary vascular resistance (mm Hg/mL per minute), recipient survival (%), and graft neutrophil infiltration (ΔAbs 460 nm /min) were measured 30 minutes after transplantation of the left lung and exclusion of the right lung from the circulation. All tested conditions significantly affect post-LTX vascular homeostasis. Inflation at 10 mm Hg pressure preserved lungs significantly better than did other pressures. There was a tendency for room air to improve all measured variables compared with 100% N 2 or 100% O 2 and a significant improvement in recipient survival with room air storage. Of the 3 storage temperatures investigated, 10°C storage provided the best preservation in terms of Pa o 2 , graft neutrophil infiltration, and survival. Conclusions —We conclude that storage at 10°C, 10 mm Hg inflation pressure, with room air establishes optimal lung storage conditions with Euro-Collins solution in this rat LTX model. These data suggest that these conditions should be used to evaluate new and potentially improved preservation strategies.