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 Δ PO₂ 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.