CONTROLLED REPERFUSION PROTECTS LUNG GRAFTS DURING A TRANSIENT EARLY INCREASE IN PERMEABILITY

Background. We have previously shown that an initial 10-minute period of low-pressure reperfusion prevents the lung graft dysfunction that f ollows physiologic-pressure reperfusion. Possible mechanisms were inve stigated in this study. Methods. Rat lungs were reperfused ex vivo usi ng a parabiotic animal after 0-hour (groups A through C) or 24-hour (g roups D through G) storage. Reperfusion pressure was either physiologi c (groups A through D) or reduced by 50% for a specified time (groups E through G). The duration of reperfusion was 5 minutes (groups A, D, and E), 10 minutes (groups B and F), or 30 minutes (groups C and G), a t which time endothelial permeability was measured through iodine 125- labeled albumin leakage and neutrophil sequestration through tissue my eloperoxidase activity. Results. Graft function in group D deteriorate d rapidly, whereas groups E through G performed at control levels. Alb umin leakage was significantly elevated in group D; with controlled re perfusion, it was elevated after 5 minutes (group E) but had returned to baseline at 10 minutes (group F) and 30 minutes (group G). Myeloper oxidase levels were not significantly different between groups. Conclu sions. Endothelial permeability is transiently elevated in the early p hase of lung graft reperfusion. Initial low-pressure reperfusion may b e protective by preventing irreversible edema formation during this pe riod. (C) 1998 by The Society of Thoracic Surgeons.