Distribution of lung preservation solutions in parenchyma and airways: influence of atelectasis and route of delivery.

Background: Bronchial healing remains one of the dominant issues in lung transplantation. Among other factors the quality of airway protection during lung procurement may contribute to improve bronchial healing.

Methods: Thirty-three pigs were divided into four groups: controls (n = 6), those receiving antegrade delivery of Euro-Collins solution with (n = 4) and without prostacyclin (n = 9), and those receiving retrograde delivery of Euro-Collins solution (n = 14). In addition, the atelectatic and nonatelectatic regions of the lungs from all groups were compared. After preparation and cannulation, cardioplegic solution and Euro-Collins solution for lung preservation were given simultaneously. After removal of the heart the double-lung bloc was harvested. During each experiment lungs were assessed by the following methods: dye-labeled microspheres for total and regional lung perfusion, tissue water content, pulmonary artery, left atrial and left ventricular pressures, cardiac output, lung temperature, and microscopic examination. Data were expressed as mean +/- standard error of the mean.

Results And Conclusions: Our data show that (1) injection of modified dye-labeled microspheres is a useful method to determine absolute flow in lung parenchyma and airways, (2) determination of tissue water content is a simple and reproducible method to investigate the distribution of hyperosmolar lung preservation solutions, (3) atelectasis leads to a significant maldistribution of lung preservation solutions regardless of the route of delivery (0.7 +/- 0.2 versus 6.5 +/- 1.0 ml/min/gm lung wet weight, p = 0.0001) and a severe increase in water content (80.6% +/- 0.4% versus 79.0% +/- 0.5%, p = 0.024), (4) prostacyclin added to the pulmonary artery flush solution results in only a slight improvement in the distribution, and (5) retrograde delivery of Euro-Collins solution through the left atrium is technically feasible and seems to improve flow to the airways even without the addition of prostacyclin.