Effect of Blood-Air Contact on Blood-Based Perfusates for Ex Vivo Lung Perfusion Using an In Vitro Approach

Lung transplantation is critical for patients with end-stage lung disease but is limited by donor lung shortages. Ex vivo lung perfusion (EVLP) enhances lung preservation, reducing ischemic reperfusion injury (IRI) and primary graft dysfunction (PGD). This study investigated the effect of blood-air interface exposure on hemolysis and metabolic activity in EVLP by comparing open- and closed-loop systems over 24 hours. Pig blood was circulated through in vitro loops that mimicked EVLP setups. Hemolysis was found to be markedly greater in the open-loop, with an increase of 20.1±7.9 mg/dL pfHb, compared to an increase of 9.3±4.8 mg/dL pfHb in the closed-loop over 24 hours. Hemolysis in the open-loop was significantly greater compared to the static blood by 18 hours, due to increased blood-air interaction. The pH, glucose, and lactate levels were consistent across systems. These findings suggest that closed-loop EVLP systems better preserve blood quality, supporting their potential to improve lung viability and transplant outcomes.