Phosphate removal in haemodialysis: Effect of two different dialysis membranes

Summary: Phosphate removal with two different dialysis membranes (a standard cellulose acetate membrane and a high performance cellulose diacetate membrane) were studied in ten haemodialysis patients. All patients were dialysed sequentially with two membranes (surface area was 1.5 m²) against bicarbonate buffered dialysis for 4 hours three times a week. With the diacetate membrane, the instantaneous clearances of urea and phosphate after 1 hour of haemodialysis were significantly higher than with the cellulose membrane. Also, the weekly total amount of urea and phosphate removal were significantly increased with the diacetate membrane (a 15% increase in urea and a 16% increase of phosphate). Although there was a significant increase in urea reduction ratio and significantly lower post dialytic plasma urea concentration with the diacetate membrane, these for phosphate did not reach statistical significance. These data suggest that the use of the diacetate membrane potentially offer clinical benefit. However, whether 16% of phosphate removal could improve clinical control of serum phosphate levels will need further investigation.