Retrograde flush perfusion with low-potassium solutions for improvement ofexperimental pulmonary preservation

Background: Optimal preservation of post-ischemic organ function is a conti nuing challenge in clinical lung transplantation. Retrograde instillation o f preservation solutions has the theoretic advantage of achieving homogeneo us distribution in the lung because of perfusing both the pulmonary and the bronchial circulation. So far, we have seen no experimental studies that i nclude stereologic analysis of intrapulmonary edema concerning the influenc e of retrograde preservation on post-ischemic lung function after preservat ion with Perfadex and Celsior, Methods: In an extracorporeal rat model, we perfused 8 lungs, each, using e ither antegrade or retrograde perfusion technique with Celsior (CEant/CEret ) and Perfadex (PERant/PERret). Results were compared with low-potassium Eu ro-Collins. Postischemic lungs were reventilated and reperfused mechanicall y. We continuously monitored relative oxygenation capacity (ROC), pulmonary artery pressure, flush time, and wet/dry ratio. Furthermore, we used stere ologic means to evaluate edema formation. Statistics comprised different an alysis of variance models. Results: Relative oxygen capacity of CEant-protected lungs was superior to that of PERant preservation (p = 0.05). Use of PERret resulted in significa ntly higher ROC as compared with PERant (p < 0.001) and was comparable to r esults obtained with CE-preservation, which was not further improved with r etrograde application. Conclusion: Celsior provides better lung preservation than does Perfadex wh en administered antegradely. Retrograde application of Perfadex results in significant functional improvement as compared with antegrade perfusion, wh ich reaches the standard of Celsior-protected organs. Additional in vivo ex periments in combination with ultrastructural analysis are warranted to fur ther evaluate retrograde delivery of preservation solutions, which could be used in clinical lung transplantation to further optimize current results.