Aluminum removal by hemodialysis

Abstract

Aluminum kinetics were studied in 24 patients on chronic hemodialysis. All patients had elevated predialytic serum concentrations of aluminum (mean, 3.44 μmoles/liter), which correlated significantly with the ingestion of aluminum hydroxide (P < 0.01). Simultaneous measurements of aluminum in plasma and ultrafiltrate revealed an ultrafiltrability of about 20% of total plasma aluminum, thus suggesting that 80% of aluminum is protein bound. When a dialysate with a very low aluminum content (varying from 0.1 to 0.3 μmoles/liter) was used, mean values across the dialyzer were 3.20 and 2.67 μmoles/liter, respectively, showing a significant decrease of plasma aluminum during dialyzer passage (P < 0.0001). It could be shown that dialysance of aluminum depends on the concentration gradient between the free diffusible plasma aluminum and the dialysate aluminum concentration. After 6 hours of dialysis, plasma aluminum concentrations were significantly lower than were predialysis values (P < 0.0001). We conclude that a negative aluminum balance during hemodialysis can be assumed as long as the aluminum concentration of free diffusible plasma aluminum lies above the aluminum concentration of the dialysate.