Lung edema formation during cold perfusion: important differences between rat and porcine lung.

Background: The aim of this study was to investigate the effect of different perfusion pressures on edema formation during cold flush perfusion with the 2 most commonly used preservation solutions in clinical lung transplantation: Euro-Collins and Perfadex solutions.

Methods: Isolated rat and porcine lungs were perfused for 3 minutes at 4 degrees C to 8 degrees C at a pressure of either 10, 15 or 20 mm Hg. Weight gain was recorded continuously. Weight gain per minute was calculated after the first phase of rapid weight gain was completed.

Results: In the rat model, perfusion pressure of 10 mm Hg resulted in a macro- and microscopically apparent edema, irrespective of the type of preservation solution. Perfusion pressures of 10, 15 and 20 mm Hg have weight gains of 100%, 150% and 350%, respectively, after 3 minutes of perfusion. The corresponding weight gain per minute was 18%, 31% and 84% of the initial weight. There were no statistically significant differences in weight gain between the different solutions at equal perfusion pressure. In the porcine model the flow was extremely low at 10 mm Hg and no weight gain was registered, whereas the weight gain per minute at 15 and 20 mm Hg was 1.0% and 2.1% of the initial weight.

Conclusions: In porcine lungs, cold perfusion at 20 mm Hg gives minimal edema formulation, whereas in rat lungs the edema formation is deleterious, irrespective of the solution used.