A study on the effectiveness of pulmonary flushing for lung preservation

Abstract

The effect of pulmonary flushing prior to lung preservation was studied using an ex vivo perfusing rabbit model. The grafts were divided into the following five groups : Group I ; surface cooling without flushing (n=6), Group II ; flushed in vivo with intracellular solution (A solution) (n = 6), Group III ; flushed ex vivo with A solution (n = 6), Group IV ;flushed in vivo with extracellular (B solution) (n=6), Group V : flushed ex vivo with B solution (n=6). After 18 hours' preservation at 8°C, the function of preserved grafts was examined for 60 minutes with a closed circuit system.In flushing with A solution, the pressure increased after 2 minutes (p <0.01) and the perfusion volume decreased after 4 minutes (p<0.01), while the flow of the B solution groups was constant throughout. The cooling effect, shown by the effluent temperature, and the flushing effect, measured in the in vivo group compared with the ex vivo groups (p<0.050.01). The flushing of Group V was most effective from the three points of view of perfusion, cooling and washing out.In the functional assessment of preserved grafts, Groups, II, III and IV dropped out due to permeability injury within 20 minute. Group V had better graft function in blood gas data, perfusion pressure, tidal volume, the perfusate decrement, and wet-dry ration (p < 0.050.01), compared with Group I.We conclude that the ex vivo flushing with extracellular solution in the best lung preservation method, and is more useful than surface cooling only.