ADEQUACY OF DIALYSIS - TRACE-ELEMENTS IN DIALYSIS FLUIDS

A number of considerations suggest that trace element disturbances mig ht occur in dialysed patients. These must at least in part be ascribed to the dialysis treatment itself during which these constituents may either be transferred to or removed from the patient. Tap water must b e considered as the main source of dialysate trace metal contamination . These can adequately be removed during water treatment provided that , in addition to softening and deionization, reverse osmosis is availa ble, However, even in the presence of the latter devices the possibili ty of serious contamination of the dialysis fluids leading to either c hronic or acute intoxications still exists. The addition of chemical c oncentrates may also contribute to the increased concentrations of a n umber of trace metals. The toxic effects of aluminium in dialysis pati ents are well known and at the present time the element is still respo nsible for the greater part of trace metal-related problems in dialysi s patients. Hence, the need for regular monitoring of aluminium cannot be ruled out at present. Strategies for diagnosis and treatment of al uminium overload have been updated. Recent studies demonstrated the ef ficacy of low desferrioxamine doses in diagnosis and treatment of alum inium overload, and optimal schedules for administration of the chelat or and duration of treatment have been presented. Recently, in an epid emiological survey serum silicon concentrations in dialysis patients w ere found to be increased up to 100-fold compared to subjects with nor mal renal function. Moreover, it was noted that silicon concentrations in the dialysis population differ from one centre to another and that increased levels are due to either the use of silicon-contaminated di alysis fluids or an increased oral intake of the element originating f rom a high silicon content in the drinking water. Besides aluminium an d silicon, a transfer towards the patients during dialysis has also be en reported for a number of other elements including copper, zinc, nic kel, strontium and chromium. The possible consequences of dialysate co ntamination with these elements will briefly be dealt with in the pres ent paper. In contrast to trace metal accumulation, removal of trace m etals during dialysis may at least in part contribute to the relative deficiency of particular essential elements. Selenium deficiency has r epeatedly been observed. in view of the element's well-known essential role in glutathion peroxidase activity and the association of its def iciency with the development of some malignant diseases, further studi es on the clinical impact of decreased serum selenium in dialysis pati ents are worthwhile. In conclusion, trace metal dialysate contaminatio n/depletion may contribute to the disturbed trace element concentratio n in dialysis patients. Aluminium accumulation is still an important p roblem in clinical nephrology. The clinical importance of the accumula tion/deficiency of trace elements other than aluminium is not yet full y understood and deserves further investigation.