Comparison of Different Membranes for Continuous Renal Replacement Therapies: An In Vitro Study

Area of Science:

• Nephrology
• Biomedical Engineering
• Critical Care Medicine

Background:

• Inflammatory mediators significantly contribute to acute kidney injury (AKI) development and progression.
• Continuous renal replacement therapy (CRRT) is employed to mitigate AKI by removing these mediators.
• Different CRRT filters, including AN69-M, AN69-ST, and HF1400, utilize varying mechanisms to target molecules of different sizes.

Purpose of the Study:

• To characterize and compare the in vitro removal performance of AN69-M, AN69-ST, and HF1400 filters during a simulated 72-hour CRRT procedure.
• To assess the clearance efficiency of these filters for key molecules such as urea, vancomycin, interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-α), and beta-2 microglobulin (β2M).

Main Methods:

• A 72-hour in vitro simulated CRRT procedure was conducted.
• The clearance performance of AN69-M, AN69-ST, and HF1400 filters was evaluated for urea, vancomycin, IL-8, TNF-α, and β2M.
• Adsorption and hydrogel water repartition properties of the filters were analyzed.

Main Results:

• AN69-M and AN69-ST filters maintained stable urea clearance, unlike HF1400.
• AN69 filters showed stable vancomycin clearance, whereas HF1400 exhibited decreased clearance.
• AN69 filters demonstrated significantly higher removal of IL-8 primarily through adsorption compared to HF1400.
• AN69-ST exhibited higher TNF-α clearance than AN69-M and HF1400.
• Both AN69-based filters showed higher β2M clearance.
• AN69-ST displayed a higher percentage of bound water compared to AN69-M.

Conclusions:

• CRRT filter clearance profiles are dependent on their intrinsic properties.
• AN69-based filters exhibit distinct and often superior performance in removing inflammatory mediators and specific molecules compared to the HF1400 filter.
• Further research is warranted to correlate these in vitro findings with clinical outcomes and optimize CRRT strategies.