Continuous Blood Gas Control Based on Active Disturbance Rejection Control During Ex Vivo Porcine Liver Perfusion.

Area of Science:

• Organ transplantation research
• Extracorporeal circulation technologies
• Physiological monitoring systems

Background:

• Membrane oxygenators are crucial for extracorporeal gas exchange, requiring precise blood gas monitoring.
• Normothermic machine perfusion (NMP) for ex vivo liver transplantation faces challenges in maintaining physiological blood gas levels due to complexity and cost.
• Existing methods for blood gas monitoring during NMP can be invasive and expensive.

Purpose of the Study:

• To introduce a noninvasive and economical method for regulating blood gas during NMP of ex vivo porcine livers.
• To demonstrate the feasibility of real-time blood gas adjustments without an online blood gas analyzer.
• To establish a closed-loop control system for maintaining physiological blood gas parameters.

Main Methods:

• Monitoring gas fractions at the oxygenator outlet.
• Developing multivariate linear regression (MLR) models to correlate gas fractions with blood gas levels.
• Implementing active disturbance rejection control (ADRC) for closed-loop regulation of blood gas parameters.
• Utilizing target setpoints for gas fractions to guide the control system.

Main Results:

• The proposed method successfully maintained blood gas levels within physiological ranges during 24 hours of ex vivo porcine liver perfusion.
• Achieved oxygen partial pressure: 150.36 ± 3.33 mmHg.
• Achieved carbon dioxide partial pressure: 41.34 ± 0.91 mmHg.

Conclusions:

• Active disturbance rejection control (ADRC)-based regulation of oxygenator outlet gas fractions is a viable strategy for blood gas management.
• This noninvasive approach offers an effective and potentially more economical solution for prolonged ex vivo liver perfusion.
• The findings support the use of this method in future applications of NMP for organ preservation and transplantation.