Hypothermic preservation of isolated rat lungs in modified bicarbonate buffer, EuroCollins solution or St Thomas' Hospital cardioplegic solution

Objectives: inadequate preservation solutions limit lung storage times and, consequently, transplant programs. To address this problem we established an isolated, ventilated and perfused rat lung preparation. Here we report t he effects of hypothermic storage in EuroCollins solution, St Thomas' Hospi tal cardioplegic solution and a modified bicarbonate buffer solution. Metho ds: Lungs from male Wistar rats (230-330 g) were perfused via the pulmonary artery with modified bicarbonate buffer (37 degrees C, 15 ml/min, constant flow) and ventilated by positive pressure (tidal volume:1.6-1.8 ml, 80 bre aths/min). Vascular resistance (pulmonary artery pressure:perfusate flow ra tio) and airways compliance (tidal volume:tracheal pressure ratio) were mea sured. After a control perfusion period (20 min), lungs were flushed with, then immersed in, bicarbonate buffer (4 degrees C) for varying periods (0-2 4 h). After storage, lung function was assessed during 20 min reperfusion, Having established a suitable period for study, storage in EuroCollins, St Thomas' Hospital cardioplegic solution or bicarbonate buffer were compared. Results: Pulmonary compliance (ml/cmH(2)O) was significantly (P < 0.05) re duced in lungs stored for 6 h in modified bicarbonate buffer (0.026 +/- 0.0 08) EuroCollins solution (0.013 +/- 0.002) or St Thomas' Hospital solution (0.025 +/- 0.005) compared to unstored lungs (0.068 +/- 0.007), Vascular re sistance, (1.32 +/- 0.13 cmH(2)O/ml per min) in unstored lungs, was similar in lungs stored in St Thomas' Hospital solution but increased significantl y in lungs stored in modified bicarbonate buffer (3.22 +/- 0.78 cmH(2)O/ml per min) or EuroCollins solution (4.66 +/- 0.57 cmH(2)O/ml per min). Conclu sions: Hypothermic storage of rat lungs for 6 h in modified bicarbonate buf fer or St Thomas' Hospital solution causes less increase in vascular resist ance on reperfusion than EuroCollins solution. (C) 1998 Elsevier Science B. V. All rights reserved.