Evaluation of 18-hour lung preservation with oxygenated blood for optimal oxygen delivery

Background. Previous studies have shown that availability of oxygen during lung preservation to maintain aerobic metabolism may be essential for the optimal viability of preserved lung tissue. The purpose of this study was to evaluate lung preservation with oxygenated blood for optimal oxygen delivery to the lung graft in a rabbit model. Methods. Eighteen excised rabbit lungs were flushed and stored for 18 hours at 10°C with one of the following: Euro-Collins solution (EC; n = 6), oxygenated homologous blood (OB; n = 6), or low-potassium dextran solution (LPD; n = 6). Poststorage lung functions were evaluated with isolated, blood-perfused lung model for 10 minutes. Results. The mean oxygen tensions after reperfusion for the EC, OB, and LPD groups (47.0 ± 2.8, 76.9 ± 13.1, 96.2 ± 10.9 mm Hg at 10 minutes, respectively) were significantly different throughout the perfusion period (EC < OB < LPD, p < 0.05; EC < LPD, p < 0.01). Pulmonary artery pressure during the reperfusion period in the EC group (35.8 ± 4.4 mm Hg at 10 minutes) was higher than that in the OB and LPD groups (29.8 ± 4.3 and 22.4 ± 2.2 mm Hg, respectively) (EC > OB, EC > LPD, p < 0.05). However, the E-selectin level in the reperfused blood in the OB group (5.04 ± 0.24 ng/mL) was significantly elevated compared with that in other groups (EC, 3.56 ± 0.54; LPD, 2.92 ± 0.35 ng/mL, p < 0.05), which indicated enhanced neutrophil recruitment in the OB group. Comparisons of thrombomodulin and endothelin among the three groups did not reach statistical significance. Conclusions. We conclude that OB may enhance lung preservation as compared with EC solution, probably through its enriched oxygen delivery during storage and extracellular composition. However, the availability of oxygenated blood does not exceed that of LPD solution because of augmented neutrophil recruitment, which may activate neutrophil–endothelial interactions.