Potassium-reduced lung preservation solutions: a screening study.

In recent years several potassium-reduced solutions have been developed for improvement of pulmonary preservation. A comparison of these solutions in a single study, however, has not yet been performed. In an extracorporeal working rat heart-lung model (n = 7/group) lungs were preserved with 20 ml Euro-Collins (EC), low potassium EC (LPEC), low potassium 2% dextran (LPD), ET-Kyoto (ETK) or low potassium 5% dextran (Perfadex) solution, while hearts were arrested with 10 ml St. Thomas' cardioplegia. Lungs of controls were not perfused. The heart-lung blocks were stored for 2 h at 10 degrees C. Thereafter, heart-lung blocks were extracorporeally perfused with Krebs-Henseleit solution with washed bovine red blood cells. Coronaries were perfused with oxygenated perfusate. Lungs were perfused via the working right ventricle with deoxygenated perfusate and ventilated with room air. Oxygenation capacity (dPO2) and pulmonary vascular resistance (PVR) were measured. Reperfusion/ventilation was performed for 40 min. At the end of the experiment the wet to dry (W/D) ratio of lungs and light microscopic assessment of the degree of edema (0-4) were performed. All potassium-reduced solutions showed superior dPO2 and a lower PVR than EC and controls while LPEC exhibited the most stable dPO2 and lowest PVR after 30 min reperfusion. The W/D ratio of all potassium-reduced groups was lower than the ratio of EC and controls. In LPEC, ETK and Perfadex the least degree of edema was noted. All solutions used in this study are superior to regular EC. However, when compared directly, LPEC perfused lungs showed better functional preservation than all other alternative solutions.