Data acquisition system for dialysis machines. A model for membrane hydraulic permeability

Area of Science:

• Nephrology
• Biomedical Engineering
• Materials Science

Background:

• Membrane permeability is crucial for dialyzer efficiency.
• Protein cake formation on dialyzer membranes reduces ultrafiltration and convective fluxes during dialysis.
• Accurate assessment of real-time membrane hydraulic permeability is essential for optimizing hemodialysis performance.

Purpose of the Study:

• To evaluate the actual hydraulic permeability of high-flux polysulfone membranes during hemodiafiltration.
• To develop a mathematical model for estimating ultrafiltration (Kuf) and protein adsorption (Kc) coefficients.
• To analyze the impact of dialysis session timing on membrane permeability.

Main Methods:

• Utilized the DIB08 data acquisition system with a Fresenius 2008E dialysis machine to record real-time dialysis parameters.
• Calculated membrane hydraulic permeability (Kuf) using the formula Kuf(t) = Quf/TMP(t).
• Developed and validated a mathematical model: Kuf(t) = Kuf0 x (1 - (Kc/Kuf0) x In(t + 1)) to estimate Kuf and Kc coefficients, analyzing 31 dialysis sessions.

Main Results:

• A mathematical model was successfully derived to estimate real-time membrane hydraulic permeability and protein adsorption.
• Midweek dialysis sessions (Group 2 and 3) exhibited higher membrane hydraulic permeability compared to the first session (Group 1).
• Higher permeability in midweek sessions correlated with lower ultrafiltration rates and reduced protein cake formation (lower Kc).

Conclusions:

• The developed data acquisition system and mathematical model enable real-time assessment of membrane hydraulic permeability during hemodialysis.
• Dialysis session timing influences membrane protein fouling, impacting hydraulic permeability.
• Understanding these dynamics allows for better prediction and optimization of dialyzer performance.