A new concept for successful long-term pulmonary preservation in a dog model

We developed a dextran-glucose-based extracellular perfusion solution (DGX) that supports limited aerobic metabolism to maintain cellular integrity of an inflated donor lung during long-term ischemia and a storage temperature of 10 degrees C. In a dog model, we compared respiratory and hemodynamic function of orthotopically transplanted left lungs preserved using this method (DGX, group I, n = 6) with function of those preserved with EuroCollins solution (EC) stored at a temperature of 4 degrees C (group II, n = 6). All lungs were inflated with room air and stored for 12 hr. Pulmonary function was monitored for 5 hr of reperfusion. Values expressed below are group means with standard deviation. Statistical significance was calculated using a two-tailed t test. For PO2 (mmHg) (FiO2 = 0.4), group I (EC): control = 193 +/- 8, 30 min p.o. = 87 +/- 20*, 300 min p.o. = 174 +/- 13*; and group II (DGX): control = 217 +/- 28, 30 min p.o. = 184 +/- 46*, 300 min p.o. = 248 +/- 5*. For pulmonary vascular resistance (dynes), group I: control = 389 +/- 22, 30 min p.o. = 1209 +/- 301, 300 min p.o. = 1025 +/- 204*; and group II: control = 401 +/- 31, 30 min p.o. = 522 +/- 129, 300 min p.o. = 458 +/- 137* (*P < 0.05 DGX vs. EC). Gas analysis performed on air samples taken from the ischemic donor lung immediately after harvest and after 12-hr storage showed (calculated as group means) a significant decrease of PO2 and a significant increase of PCO2, respectively. Histology of the lungs after 5 hr of reperfusion showed essentially normal-appearing lungs in the DGX group, whereas lungs in the EC group showed thickening of the intra-alveolar septi, marked cellular infiltration, and accumulation of protein-like material in the alveoli. In this study, preservation with DGX resulted in satisfactory respiratory and hemodynamic function of the transplanted lung even after 12 hr of ischemia. It does not cause an increase of pulmonary vascular resistance as seen after preservation with EC. Data from the intrabronchial air analysis of the donor lung suggest that aerobic metabolism continues even under preservation conditions.