Objective: The present study was performed to investigate the influence of different routes of perfusion on the distribution of the preservation solutions in the lung parenchyma and upper airways. Methods: Pigs were divided into four groups: control (n = 6), pulmonary artery (PA) (n = 6), simultaneous PA + bronchial artery (DA) (n = 8), and retrograde delivery (n = 6). After preparation and cannulation, cardioplegia solution and Euro-Collins solution (ECS) for lung preservation were given simultaneously. After removal of the heart, the double lung bloc was harvested. Following parameters were assessed: total and regional perfusion (dye-labeled microspheres), tissue water content, PA, aorta, left atrial and left ventricular pressures, cardiac output and lung temperature. Results: Our data show that flow of the ECS in lung parenchyma did not reach control values (9.4 +/- 1.0 ml/min per g lung wet weight) regardless of the route of delivery (PA 6.3 +/- 1.5, PA + BA 4.8 +/- 0.9, retrograde 2.7 +/- 0.9 ml/min per g lung wet weight). However, flow in the proximal and distal trachea were significantly increased by PA + BA delivery (0.970 +/- 0.4, respectively, 0.380 +/- 0.2 ml/min per g) in comparison with PA (0.023 +/- 0.007, respectively, 0.024 +/- 0.070 ml/min per g), retrograde (0.009 +/- 0.003, respectively, 0.021 +/- 0.006 ml/min per g) and control experiments (0.125 +/- 0.0018, respectively, 0.105 +/- 0.012 ml/g per min). Similarly the highest flow rates in the right main bronchus were achieved by PA + BA delivery (1.04 +/- 0.4 ml/min per g) in comparison with 0.11 +/- 0.03 in control, 0.033 +/- 0.008 in PA, and 0.019 +/- 0.005 ml/min per g in retrograde group. Flows in the left main bronchus were 0.09 +/- 0.02 ml/min per g in control, 0.045 +/- 0.012 ml/min per g in PA, and 0.027 +/- 0.006 ml/min per g in retrograde group. The flow rates were significantly (P = 0.001) increased by PA + BA delivery of the storage solution (0.97 +/- 0.3 ml/min per g). Conclusions: Our data show that the distribution of ECS for lung preservation is significantly improved in airway tissues (trachea and bronchi) if a simultaneous PA + BA delivery is used. (C) 1999 Elsevier Science B.V. All rights reserved.