Influence of pH of preservation solution on lung viability

Recently, various solutions for organ preservation have been introduced. Despite much debate regarding the composition of preservation solutions, the ideal pH of a preservation solution has not been determined. We investigated the effects of the pH of a lung preservation solution on viability using an isolated, ventilated lung perfusion model. Initially, we performed flush perfusion with solutions of five different pH groups (6.60, 7.00, 7.40, 7.80 and 8.20, measured at 10 degrees C). Lungs perfused with pH 6.60 solution had a significantly higher pulmonary vascular resistance than those perfused with pH 7.40, 7.80 and 8.20 solutions. Blood was washed out completely and uniformly with solutions of pH 7.40 and 7.80. After preservation the arterial oxygen tension was significantly greater in pH 7.40 and 7.80 groups than in pH 6.60, 7.00, or 8.20 groups. Moreover, pulmonary artery pressure, airway pressure, and wet/dry weight ratios in the pH 7.40 and 7.80 groups were lower than in the others. We conclude that for both pulmonary flush and storage preservation, solutions of pH 7.40 to pH 7.80 are optimal for lung preservation.