The use of ion exchange to remove aluminum from water used in hemodialysis.

Abstract

Since the established techniques for removing aluminum from the water used in dialysis (reverse osmosis and deionization) are relatively complex and expensive, it was decided to investigate a number of simple ion-exchange techniques. In 48 of 217 tap water samples obtained from 61 home hemodialysis patients in southeast Scotland, the aluminum content exceeded 2 mumol/L (54 micrograms/L)--a level that has been associated with dialysis dementia and fracturing osteodystrophy. Dialysate prepared from this water after softening had approximately half this aluminum content, but in 17 instances the concentration still exceeded 2 mumol/L. In vitro studies showed that the anion-exchange resin IRA 400 (Rohm-Haas, Philadelphia) in the chloride phase was very effective at removing aluminum. A commercial water softener was modified by the addition of this resin, and installed in the home dialysis training unit at the Princess Alexandra Hospital in Brisbane. Over a 12-month period in which the tap water aluminum content averaged over 10 mumol/L (270 micrograms/L), the product water had an aluminum content consistently under 2 mumol/L, being under 1 mumol/L (27 micrograms/L) on 19 out of 20 occasions. The modified softener was regenerated with a saturated sodium chloride solution at 2-week intervals, using the manufacturer's protocol for the unmodified softener. Provided that dialysate and plasma aluminum levels are monitored on a regular basis, it is felt that this simple technique of aluminum removal may be appropriate for many home hemodialysis situations.