ABSTRACT
Hypothermia during lung preservation decreases metabolic processes. After the rabbit lung was flushed with modified Euro-Collins solution, heart-lung block was harvested and the left lung was assessed after ligation of the right pulmonary artery and right main-stem bronchus. Heart-lung block was immersed in the same solution for 6 hours. The modified Euro-Collins solution and storage temperature of group 1( 10 cases ) was 4 degrees C, group 2( 10 cases ) was 10 degrees C. On completion of the storage period, the left lung was ventilated and reperfused with blood which used a cross-circulating paracorporeal rabbit as a " biologic deoxygenator " for 60 minutes. Pulmonary artery pressure, airway pressure, difference in oxygen tension between inflow and outflow perfusate and degree of pulmonary edema were assessed at 10-minute intervals while the left lung was ventilated at 0.8 of the inspired oxygen fraction. The mean pulmonary venous oxygen tensions at 10 and 60 minutes after reperfusion were 209.52 +/- 42.46 and 103.48 +/- 15.96 mmHg in group I versus 247.78 +/- 36.19 and 147.91 +/- 11.07 mmHg in group II( p = 0.049, <0.0001 ). The mean alveolar-arterial oxygen differences at 20 and 60 minutes after reperfusion were 357.95 +/- 12.84 and 437.31 +/- 14.26 mmHg in group I versus 310.88 +/- 33.47 and 390.93 +/- 15.86 mmHg in group II( p = 0.0092, <0.0001 ). The mean pulmonary arterial pressures at 10 and 60 minutes after reperfusion were 40.56 +/- 18.66 and 87.22 +/- 17.22 mmHg in group I versus 31.22 +/- 6.84 and 65.78 +/- 11.02 mmHg in group II( p = 0.048, 0.0062 ). The mean pulmonary vascular resistances at 10 and 60 minutes after reperfusion were 2.69 +/- 0.85 and 4.36 +/- 0.86 mmHg/ml/min in group I versus 1.99 +/- 0.39 and 3.29 +/- 0.55 mmHg/ml/min in group II( p = 0.0323, 0.0062 ). There were no difference between groups in peak airway pressure, lung compliance and degree of pulmonary edema. In conclusion that preservation of lung at 10 degrees C was superior to preservation at 4 degrees C.