Abstract

Objective: Preservation solutions containing high potassium concentrations may damage vascular endothelium in the graft. To clarify the isolated effect of potassium concentration on lung preservation, standard Euro-Collins solution was compared to low potassium Euro-Collins solution.

Methods: Canine lungs were perfused in situ at 60 ml/kg with cold Euro-Collins solution (group I; n = 6) or low potassium Euro-Collins solution (group II; n = 6) and stored at 4° C for 2.5 hr. The left lung was transplanted and 10 min. later the right pulmonary artery was ligated. Following 4 hours of reperfusion the assessment of the graft function was monitored by blood gases and hemodynamic parameters. Cellular preservation was determined using light and transmission electron microscopy.

Results: Group II showed significantly better PaO₂ following 2 hr and 4 hr of reperfusion (154.0 ± 12.6 mm Hg versus 118.5 ± 7.1 mm Hg; 142.0 ± 9.0 mm Hg versus 107.0 ± 9.7 mm Hg, p < 0.05). Pulmonary artery pressure was significantly lower in group II at 10 min. and 4 hr after reperfusion (33.5 ± 1.8 mm Hg versus 38.7 ± 1.0 mm Hg; 28.5 ± 1.1 mm Hg versus 34.7 ± 2.5 mm Hg, p < 0.05). Alveolocapillary distance and type 1 pneumocyte thickness were significantly lower in group II at 3 hr after transplantation (447.9 ± 70.7 nm versus 815.4 ± 117.9 nm; 118.0 ± 23.2 nm versus 220.4 ± 32.6 nm, p < 0.05). Mean basal membrane thickness was significantly lower in group II at 1 hr 50 min. and 3 hr of reperfusion (125.7 ± 12.7 nm versus 220.0 ± 26.8 nm; 102.2 ± 17.1 nm versus 328.8 ± 70.6 nm, p < 0.05).

Conclusion: The use of low potassium Euro-Collins solution for preservation is associated with improved post-operative graft function and better cellular preservation compared to standard Euro-Collins solution in a canine model of single lung transplantation.