Effects of University of Wisconsin and Euro-Collins solutions on interstitial pulmonary edema in isolated rat lungs.

Abstract

Macromolecules are present in lung preservation solutions to limit liquid filtration out of the pulmonary circulation and minimize pulmonary edema. We tested the effectiveness of these molecules by measuring interstitial edema in rat lungs perfused with macromolecular solutions (University of Wisconsin [UW] solution and Euro-Collins solution supplemented with modified pentastarch [pentafraction, PEN]) or with solutions that lacked macromolecules (UW solution with PEN and Euro-Collins solution.) The lungs were inflated with air and perfused with one of the test solutions, then rapidly frozen and prepared for histological analysis. From tissue sections, we measured cross-sectional areas of pulmonary arteries and veins, and also measured cross-sectional areas of the interstitial spaces surrounding arteries and veins. We then calculated the interstitium-to-vessel cross-sectional area ratio. In lungs perfused with macromolecular solutions these ratios were 0.09+/-0.15 and 0.53+/-0.56 (mean +/- SD) for UW solution and Euro-Collins solutions solution with PEN, respectively (P</=0.05). In lungs perfused with solutions that lacked macromolecules, area ratios were 0.48+/-0.88 and 1.95+/-1.82 for UW solution without PEN and Euro-Collins solution, respectively (P</=0.05). Solutions containing PEN caused less interstitial expansion than their counterparts that lacked it, but UW solution without PEN caused interstitial expansion equal to that of Euro-Collins solution with PEN. We conclude that macromolecules limit edema formation, but other constituents of UW solution limit edema formation also.