Small intrapulmonary artery lung prototypes. Mathematical modeling of gas transfer

Area of Science:

• Biomedical Engineering
• Chemical Engineering
• Respiratory Physiology

Background:

• Artificial lungs require efficient gas exchange.
• Understanding gas transfer dynamics in microporous fibers is crucial for device design.
• Previous models did not fully capture complex flow conditions within artificial lungs.

Purpose of the Study:

• To develop and validate diffusion models for gas transfer analysis in an intravascular artificial lung.
• To investigate the influence of fiber geometry and gas supply conditions on gas transfer efficiency.
• To estimate the liquid phase mass transfer coefficient (kAI) under different operational modes.

Main Methods:

• Developed a convective-diffusion (CD) model for constant gas supply pressure.
• Developed a well-mixed (WM) cycled pressure model for time-varying gas supply.
• Regressed experimental gas transfer data against the CD model to estimate kAI.
• Compared WM model predictions with experimental data for cycled pressure conditions.

Main Results:

• CD model regression yielded kAI values influenced by both parallel and perpendicular flow across fibers.
• Gas transfer was affected by fiber orientation within the artificial lung.
• WM model accurately predicted enhanced carbon dioxide and oxygen excretion under cycled pressure.
• WM model did not account for reduced transfer efficiency with increasing fiber length.

Conclusions:

• The developed diffusion models provide insights into gas transfer mechanisms in artificial lungs.
• Fiber geometry and operational pressure significantly impact gas transfer efficiency.
• Further refinement of the WM model is needed to incorporate fiber length effects for improved prediction accuracy.