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

Area of Science:

• Cardiovascular and Respiratory System Physiology
• Transplantation Medicine
• Biomaterials and Medical Devices

Background:

• Lung transplantation is a vital treatment for end-stage lung disease, but donor lung scarcity remains a significant challenge.
• Ex vivo lung perfusion (EVLP) is an emerging technique to improve donor lung preservation, mitigating ischemic reperfusion injury (IRI) and primary graft dysfunction (PGD).
• The impact of the blood-air interface within EVLP systems on blood product quality, specifically hemolysis, requires further investigation.

Purpose of the Study:

• To investigate the effect of blood-air interface exposure on hemolysis and metabolic activity during ex vivo lung perfusion (EVLP).
• To compare hemolysis and metabolic changes between open- and closed-loop EVLP systems over a 24-hour period.
• To assess the potential of closed-loop EVLP systems in preserving blood quality for improved lung transplant outcomes.

Main Methods:

• Utilized in vitro loops simulating open- and closed-loop EVLP setups with pig blood.
• Circulated blood through the systems for 24 hours to mimic EVLP conditions.
• Measured hemolysis (pfHb levels) and monitored metabolic parameters (pH, glucose, lactate) at regular intervals.

Main Results:

• Hemolysis increased significantly more in the open-loop system (20.1±7.9 mg/dL pfHb) compared to the closed-loop system (9.3±4.8 mg/dL pfHb) over 24 hours.
• Open-loop systems exhibited significantly greater hemolysis than static blood by 18 hours, attributed to increased blood-air interaction.
• Metabolic parameters including pH, glucose, and lactate levels remained consistent across both open- and closed-loop systems.

Conclusions:

• Closed-loop EVLP systems demonstrate superior preservation of blood quality by minimizing hemolysis compared to open-loop systems.
• Reduced hemolysis in closed-loop EVLP suggests improved blood compatibility and potentially enhanced donor lung viability.
• These findings support the use of closed-loop EVLP systems to optimize donor lung preservation and improve outcomes in lung transplantation.