Closed circuit perfusion of an isolated rabbit lung. A new model for the evaluation of preservation quality of stored lungs.

The comparison of different preservation methods in lung transplantation demands a well standardized and reproducible animal model. The aim of this study was to establish as in vitro model in which the oxygenation capacity of the lung can be investigated over an extended period of time. Heart-lung blocks from 6 New Zealand white rabbits were harvested, the pulmonary artery and the left ventricle cannulated and the lungs perfused with whole rabbit blood by means of a roller pump and ventilated with room air. A dialyser was installed into the closed circuit perfusion for continuous deoxygenation of the oxygen-saturated blood gained from the left ventricle. Throughout the stable perfusion period the average arterial and venous partial oxygen pressure (pO2) levels were 105.8 +/- 15.5 mmHg and 55.2 +/- 6.2, respectively (P < 0.05). The average peak airway pressure steadily increased from 10.7 +/- 1.2 mmHg at the start of reperfusion to 21 +/- 14.4 mmHg after 180 minutes (P = NS). With this experimental setting it is possible to maintain stable conditions (i.e. constant venous and arterial blood gases) for at least 180 minutes. It is therefore feasible to compare the influences of different preservation methods on the quality of lung function.