Aluminum transport and dialysance during haemodialysis

Aluminum transfer and dialysance during haemodialysis and plasma aluminum concentrations in haemodialysis patients were examined. Plasma aluminum in 30 volunteer outpatients tended to decrease after 5-hour dialysis (6.35 +/- 3.02 micrograms/dl before haemodialysis; 5.41 +/- 2.60 micrograms/dl after haemodialysis). The decrease was mainly due to diffusion despite haemoconcentration evidenced by a significant increase in the haematocrit and total plasma protein during dialysis. To study the changes resulting from diffusion, we measured aluminum in the arterial blood and in the dialysate at the inflow and outflow sites of the dialyzer. There was a non-significant decrease in the plasma aluminum of arterial blood from 6.20 +/- 2.90 to 5.64 +/- 2.55 micrograms/dl, but a significant increase in the dialysate aluminum from 0.38 +/- 0.18 micrograms/dl to 1.10 +/- 0.66 micrograms/dl. Aluminum diffused across the dialyzer from the blood to the dialysate in 23 cases and into the blood in 7 others. When aluminum dialysance is high, plasma aluminum can be removed to the dialysate during haemodialysis.