Amelioration of pulmonary allograft injury by administering a second rinse solution

The use of rinse solutions before reperfusing liver allografts has been shown to reduce cell death in rats. Carolina rinse solution (an extracellular solution that contains antioxidants, vasodilators, and other substrates that help prevent ischemia-reperfusion injury) has also been shown to improve liver function clinically in liver transplant recipients. This pilot study evaluates the value of a second pulmonary artery flush before reperfusion of a lung graft.

Six groups of Sprague-Dawley rats (n = 6 each) were subjected to the following: Group 1 lungs were preserved with modified Euro-Collins solution followed by 24 hours of cold ischemia. Group 2 lungs were treated the same as group 1 but reperfused with blood. Group 3 lungs were preserved in Carolina rinse solution followed by 24 hours of cold ischemia. Group 4 lungs were treated the same as group 3 lungs and then reperfused with blood. Lungs in groups 5 and 6 were preserved with Euro-Collins solution, stored cold for 24 hours, and then rinsed with Euro-Collins or Carolina rinse solution, respectively, before reperfusion with blood. Lungs were subsequently stained with trypan blue solution for 5 minutes. Lung blocks were fixed and embedded in water-soluble methacrylate. Trypan blue--stained nuclei in nonviable endothelial cells and alveolar pneumocytes were counted in 10 different fields.

Groups 1 and 3, preserved with Euro-Collins and Carolina rinse solutions for 24 hours but not reperfused with blood, had significantly more viable endothelial cells (groups 1 and 3 vs group 2, p < 0.0001; group 3 vs group 4, p < 0.02) and pneumocytes (group 1 vs groups 2 and 4, group 3 versus group 2, p < 0.0001; group 3 vs group 4; p < 0.035) than groups 2 and 4, which were subsequently reperfused with blood. Groups 5 and 6, which received a second rinse, also had significantly more viable endothelial cells (p < 0.0005) and pneumocytes (p < 0.0001) than control groups, which were not rinsed before reperfusion.

We conclude that damage to pulmonary allografts resulting from prolonged ischemia is accentuated by reperfusion with blood. We also conclude that preservation with a single flush of Euro-Collins or Carolina rinse solution does not offer adequate protection, whereas a second rinse before reperfusion significantly decreases the number of damaged cells within the allograft.