Backdiffusion or bicarbonate may stimulate complement activation during haemodialysis with low-flux membranes

Area of Science:

• Nephrology
• Biomedical Engineering
• Immunology

Background:

• Low-flux hemodialysis membranes may allow dialysate backdiffusion.
• Bicarbonate dialysate base use can influence complement system activation.
• Understanding dialysate-membrane interactions is crucial for patient safety.

Purpose of the Study:

• To investigate the influence of acetate versus bicarbonate dialysate base on complement activation.
• To assess the impact of ultrafiltration (UF) standardization on dialysate backdiffusion.
• To analyze changes in plasma protein, hematocrit, and complement C3d during hemodialysis.

Main Methods:

• Eight patients underwent hemodialysis with acetate and standardized UF (Group I).
• Eight patients underwent hemodialysis with bicarbonate and zero UF (Group II).
• Hemodialysis utilized Hemophan and cellulose acetate (CA) hollow-fiber membranes; blood samples analyzed for protein, hematocrit, and C3d at intervals.

Main Results:

• Group II showed reduced plasma protein with both Hemophan and CA membranes.
• Complement C3d levels increased at 15 minutes for both membrane types in Group II.
• Protein reduction in Group II correlated with hematocrit changes, suggesting dialysate backdiffusion.

Conclusions:

• Zero ultrafiltration with bicarbonate dialysate may promote dialysate backdiffusion.
• This backdiffusion might contribute to complement system activation (increased C3d).
• Careful management of ultrafiltration and dialysate composition is important in hemodialysis.