On the Temporal Evolution of Key Hemofilter Parameters-In Vitro Study under Co-Current Flow

Area of Science:

• Biomedical Engineering
• Fluid Mechanics

Background:

• Hemofilter (HF) performance is critical for hemodialysis and hemocatharsis.
• Accurate determination of parameters like effective permeability (K_P) and ultrafiltration coefficient (K_UF) is challenging.
• Current counter-current flow may lead to non-uniform transmembrane pressure (TMP).

Purpose of the Study:

• To demonstrate the benefits of co-current flow for unidirectional filtration and uniform TMP in hemofilters.
• To investigate the temporal evolution of key hemofilter performance parameters under co-current flow.
• To correlate protein mass flux with permeability under varying conditions.

Main Methods:

• Experimental investigation using human plasma and BSA solutions in co-current flow mode.
• Development of a fluid mechanical model to analyze flow dynamics.
• Measurement of effective permeability (K_P), ultrafiltration coefficient (K_UF), sieving coefficient (SC), and protein mass flux (M_m).

Main Results:

• Co-current flow achieved a fairly uniform local TMP, reducing axial variability.
• Improved uniformity in local TMP led to more uniform protein membrane fouling.
• Observed temporal variability and decline in K_P due to membrane fouling, impacting other parameters.
• Established a strong correlation between albumin/protein mass flux (M_m) and permeability (K_P).

Conclusions:

• Co-current flow facilitates accurate and representative data acquisition for hemofilter parameters.
• Uniform TMP under co-current flow aids in interpreting and correlating HF performance data.
• Results support further exploration of co-current flow for clinical hemocatharsis applications.