Lung function after prolonged lung preservation

Abstract

Our previous study revealed significant improvement in lung preservation with a new solution, the UCLA formula, which contains verapamil and is based on a glucose-insulin-potassium solution. In this study, we extended the preservation time up to 12 hours and, using various parameters, compared lung function after 12 hours' preservation with that after 6 hours' preservation. The left lung of 15 dogs was perfused with 300 ml of the UCLA formula (4 degrees C) and preserved for 6 hours in eight dogs (group A) and for 12 hours in the other seven dogs (group B). The preserved left lung was then autotransplanted and pulmonary function was evaluated during the following 2 weeks. The oxygen tension was monitored at 2 and 12 hours postoperatively, then daily for 1 week, and on the fourteenth postoperative day. The right pulmonary artery was temporarily occluded to assess the function of the preserved left lung alone. Oxygen tension in group A was maintained within the normal range. By contrast, in group B transient deterioration in oxygen tension was observed from the third to the fourth postoperative day (p less than 0.01), improving toward the normal range by the seventh day. Pulmonary vascular resistance was significantly elevated after transplantation in group B, improving to the normal range by the fourteenth postoperative day. Lung compliance, according to the airway pressure-tidal volume curve, also deteriorated significantly in group B (p less than 0.01), improving to the normal range within 2 weeks. Lung perfusion scintigraphy with technetium-labeled macroaggregated albumin was performed on the fourth day after the operation. The ratio of left to right pulmonary flow on the fourth postoperative day was 57.1 +/- 8.5% in group A and 52.2% +/- 12.3% in group B (no significant difference). In conclusion, temporary deterioration of lung function was observed after 12 hours of lung preservation, manifested by impaired oxygen exchange and loss of compliance.