Aluminum removal by hemodialysis

Area of Science:

• Nephrology
• Clinical Chemistry
• Toxicology

Background:

• Elevated serum aluminum is common in patients undergoing chronic hemodialysis.
• Aluminum hydroxide ingestion is a significant contributor to hyperaluminemia in this population.
• Understanding aluminum kinetics is crucial for managing toxicity in dialysis patients.

Purpose of the Study:

• To investigate aluminum kinetics in patients on chronic hemodialysis.
• To determine the effectiveness of hemodialysis with low aluminum dialysate in reducing serum aluminum levels.
• To establish the relationship between plasma and dialysate aluminum concentrations for achieving a negative aluminum balance.

Main Methods:

• Studied 24 patients on chronic hemodialysis with elevated predialytic serum aluminum.
• Measured aluminum concentrations in plasma and ultrafiltrate to assess protein binding and ultrafiltrability.
• Utilized hemodialysis with a very low aluminum content dialysate (0.1-0.3 mumoles/liter).
• Monitored plasma aluminum levels before, during, and after a 6-hour dialysis session.

Main Results:

• All patients exhibited elevated predialytic serum aluminum (mean 3.44 mumoles/liter), correlating with aluminum hydroxide intake.
• Approximately 80% of plasma aluminum was found to be protein-bound.
• Hemodialysis with low aluminum dialysate significantly decreased plasma aluminum concentrations (P < 0.0001).
• Dialysance was dependent on the concentration gradient between plasma and dialysate aluminum.

Conclusions:

• Hemodialysis with low aluminum dialysate effectively reduces serum aluminum levels in patients with hyperaluminemia.
• A negative aluminum balance is achievable during hemodialysis when dialysate aluminum concentration is lower than free diffusible plasma aluminum.
• These findings support the use of low aluminum dialysate to manage aluminum overload in hemodialysis patients.