Prolonged ex vivo lung perfusion with corrected perfusate: functional and structural benefits in swine.

BACKGROUND: During ex vivo lung perfusion (EVLP), perfusate pH, electrolyte, and glucose concentrations often deviate from physiological ranges. We evaluated the effect of a corrective solution on maintaining these parameters within physiological limits during 12 h of EVLP in a porcine model. METHODS: Twelve porcine lung blocks were harvested and cold-preserved before undergoing 12 h of normothermic EVLP. Lung blocks were randomly assigned to two groups based on the perfusate replacement strategy. All lungs were perfused with Steen solution, mean priming volume was 1,525 ± 340 and 1,325 ± 232 mL, with 100 mL (5%-9%) replaced every two hours by either fresh Steen solution (standard group, n = 6) or a modified solution designed to restore physiological composition (corrected group, n = 6). Perfusate electrolytes, glucose, cytokines, pH, partial oxygen pressure (PO₂), pulmonary vascular resistance (PVR), and compliance were measured. After EVLP, left lungs were transplanted during 4 h into donor-related pigs, while right lungs were analyzed by histology and electron microscopy. RESULTS: Perfusate correction successfully maintained electrolyte, pH, and glucose levels within target ranges during EVLP. The corrected group demonstrated higher lung compliance and oxygenation, reduced edema, more hyaline membranes, and a greater density of Kohn's pores after EVLP. PVR was similar between groups, and no significant difference in ΔPO₂ was observed post-transplantation. CONCLUSION: Maintaining physiological perfusate composition improved lung function during 12-hour EVLP in swine; however, no post-transplant benefit was observed. Further studies are warranted to assess the impact of this strategy during prolonged EVLP and to compare it with alternative approaches.