Department of Medicine, Wadsworth Veteran Administration Medical Center and UCLA, Los Angeles, California, USA, and Department of Medicine, Repatriation General Hospital, Concord, Concord NSW, Australia

Correspondence: Francisco Llach MD, Division of Nephrology (111L), Wadsworth VA Medical Center, Wilshire and Sawtelle Blvds., Los Angeles, California 90073, USA.

Received 17 August 1992; Revised 26 October 1992; Accepted 26 October 1992.

Abstract

Aluminum kinetics using bicarbonate dialysate with the sorbent system. In the REDY system a sorbent cartridge is used to regenerate the spent hemodialysate so that only six liters of dialysate are required for a treatment. The manufacturer claims that the cartridge can be used to remove aluminum from the dialysate and that it does not add aluminum to the dialysate. This claim for acetate dialysate is supported by the literature, but there are few data available relative to bicarbonate dialysate. The present study evaluates the use of bicarbonate dialysate and the REDY system in regard to aluminum kinetics both in vitro and in vivo. In vitro, the sorbent cartridge removed aluminum from dialysate prepared from water containing as much as 470 g/liter of aluminum, giving a dialysate containing less than 10 g/liter. The first 500 ml of effluent contained 13 ug/liter of aluminum but after filtration decreased to below 10 g/liter. Thus, it is unnecessary, as recommended, to discard the first effluent since this unfilterable aluminum will not pass through a dialysis membrane. In vivo, in a crossover study comparing the REDY with single pass, there were no significant differences between the pre- and post-plasma aluminum concentrations, and the dialysate aluminum remained below 4 g/liter during the dialysis. In a second in vivo study the effect of dialysate from tap water on plasma aluminum using the predialysis purification procedure was evaluated. There was no differences between the pre- and post-plasma aluminum concentration. The aluminum levels were comparable to those of the crossover study. The dialysate remained below 4 g/liter during the dialysis.