The Importance of Water Quality and Haemodialysis Fluid Composition

Abstract

Treatment of renal failure by haemodialysis uses dialysis fluid to facilitate the normalization of electrolyte and acid base abnormalities and the removal of low molecular weight uraemic compounds present in the plasma such as urea. The dialysis fluid is a continuously produced blend of treated tap water and a concentrated solution containing electrolytes, buffer, and glucose. The water used originates as drinking water but undergoes additional treatment. Recent surveys have indicated that the chemical and microbiological content of such water frequently fails to meet the requirements of established standards, and its bacterial content arising from the presence of a biofilm in the water distribution network or the hydraulic circuit of the dialysis machine is a contributory factor to the chronic inflammatory state in patients undergoing regular dialysis. The composition of the dialysis fluid plays an important role in the modulation of complications associated with end-stage renal disease, as well as those associated with the treatment itself. The avoidance of complications arising from water contaminants requires a constant and vigorous attention to water quality, whilst with the composition of electrolytes and buffer there is a trend towards greater individualization to provide a high degree of treatment tolerance.

Forthcoming Papers

“…Water for haemodialysis requires additional treatment to remove contaminants that may be present in drinking water (Hoenich and Levin 2003). The typical water treatment system for dialysis will depend upon the quality of the incoming supply.…”

“…The use of highly permeable membranes and ultrafiltration control systems may result in transfer of dissociated endotoxins and endotoxin fragments from dialysate to blood (Hoenich and Levin 2003). Therefore the water used to prepare dialysate for high-efficiency haemodialysis, needs to have a lower level of microbiological contamination than is suggested for general use as high flux membranes may have a higher absorption capacity for endotoxins than a low flux cellulosic membrane.…”

“…Nurses may be unaware that the level of microbiological contamination can increase due to biofilm being present in the water system. Bacterial fragments from the biofilm can cross the dialysis membrane and simulate an inflammatory patient response, which has been implicated in the mortality and morbidity of haemodialysis patients (Hoenich and Levin 2003).…”

“…If the standards are not achieved, then microbiological contamination can occur in the dialysate due to biofilm being present in the water distribution network or dialysis machine. Bacterial fragments that are produced due to this can cross the dialysis membrane and stimulate an inflammatory patient response (Hoenich and Levin, 2003). Biofilm is the cause of chronic, sub clinical inflammation due to repeated macrophage stimulation (Cappelli, Tetta and Canaud, 2005).…”

“…Dialysis fluid is generally made up of three components -water, 'A' concentrate and 'B' concentrate. The water originates as drinking water but via several processes becomes usable for haemodialysis (Hoenich, Ronco and Levin, 2006). The 'A' concentrate contains some acid in the form of acetate, which is why it is sometimes referred to as the 'acid bath'.…”