Purification of dialysis fluid: historical background and perspective.

When dialysis became a chronic therapy, certain clinical symptoms could be connected to the fluid quality and some form of water treatment had to be introduced. The required equipment was empirically developed and consisted of sedimentation filters, carbon filters and softeners. In the mid-1970s the toxic effect of aluminum accumulation was discovered and led to the introduction of reverse osmosis modules. When these components - prefilters, softeners and RO modules - are properly maintained, they produce water of a quality that should meet modern standards. However, the water quality could be ruined by bacterial contamination from the distribution pipes, unless the entire flow path is hygienically designed and frequently disinfected. The quality of the concentrate is also important, especially the bicarbonate component which is prone to bacterial growth. The extent of the microbiological burden in water and dialysis fluid has been brought to the attention of the dialysis community through new and sensitive detection and quantification methods for bacteria and endotoxin.

Clinical effect of purification of dialysis fluids, evidence and experience.

Microinflammation in renal failure has been the subject of numerous contributions to the literature. The bacterial contamination of dialysate and subsequent transfer of bacterial products onto the blood side is an important cause for microinflammation in hemodialysis patients. It has been suggested that the inflammatory process may not merely be an epiphenomenon but rather a pathogenetic factor in the genesis of atherosclerosis [1,2,3]. Thus, by promoting microinflammation, dialysate contamination may contribute directly to cardiovascular morbidity and mortality.

Standardization of water purification in the central dialysis fluid delivery system: validation and parametric method.

The central dialysis fluid delivery system (CDDS) has been mainly used for hemodialysis therapy in Japan. Validation and a parametric method are necessary for the quality control of dialysis fluid in CDDS. Validation is a concept for the assurance of system compatibility and product quality, and is defined as follows: the manufacturing and quality control methods including the system design and equipment of the manufacturing facility, manufacturing procedure and processes. Confirmed results must be kept within acceptable limits and they must be documented in a record. Important parameters for validating CDDS include: (1) setting the sterilized area; (2) decision of sterilization level; (3) confirmation of the maximum bio-burden; (4) performance of endotoxin retentive filter and reverse osmosis (RO) module, and (5) checkpoints of purity of dialysis water in the system. Taking the concept of validation and a parametric method in the management of CDDS into consideration enables the supply the purified dialysis fluid or the online prepared substitution fluid that meet the 2008 standards of the Japanese Society for Dialysis Therapy.

Guidance of technical management of dialysis water and dialysis fluid for the Japan Association for Clinical Engineering Technologists.

There has been remarkable medical and technological progress in Japanese dialysis therapy where more than 270 thousand patients had been treated with dialysis by the end of 2007. Clinical engineering technologists have played an important role not only in the safety treatment but also in the technological development of dialysis therapy. It is very important to supply pure dialysis fluid for both the efficacy and the safety of hemodialysis in which high permeable dialysis membranes are used. The Japanese Society for Dialysis Therapy recently issued the standard for bacterial management of fluids for hemodialysis and related therapies according to the International Organization for Standardization (ISO)/DIS 23500. In order to achieve the standard, the management of dialysis water treatment is important as well as the role of clinical engineering technologists in daily dialysis practice. Purification is defined as no contamination by chemical substances and/or microorganisms and its components. The purification consists of the design and the system structure of the water treatment equipment and dialysis fluid-supplying equipment, and the operation and management of the equipment. The guideline aims to show the minimum standard and the management method of the water treatment system and dialysis fluid-supplying equipment in order to perform hemodialysis safely. They should outline safer dialysis by the management of purification of dialysis fluid.

Silicon and aluminium interactions in haemodialysis patients.

BACKGROUND: Aluminium toxicity in dialysis patients is well described. Aluminium has a close chemical affinity with silicon. Silicon may have a role in protection against aluminium toxicity. METHODS: We measured serum aluminium and silicon levels from haemodialysis patients from four different centres. RESULTS: Though no relationship was seen across all centres combined, in one centre there was a reciprocal relationship in patients on home haemodialysis (who did not require reverse osmosis). Median (range) aluminium levels were higher, 2.2 (0.4-9.6) micromol/l when serum silicon was less than 150 micromol/l, and lower, 1.1 (0.2-2.8) micromol/l when serum silicon levels were greater than 150 micromol/l (P = 0.03). CONCLUSIONS: In patients treated by haemodialysis without reverse osmosis high serum silicon concentrations were associated with lower serum aluminium concentrations than those with low serum silicon. Further work needs to confirm a preventative role for silicon in the accumulation and subsequent toxicity of aluminium in dialysis patients.

[Experimental and clinical studies of methods for regenerating the dialysis solution]. / Eksperimental'noe i klinicheskoe izuchenie metodov regeneratsii dializiruiushchego rastvora.

The efficacy of artificial kidney apparatuses was assessed by using 5 different methods of regenerating the dialysis solution. In the series of model experiments the authors have studied the quality of the solution purification from urea, creatinine, uric acid, nonorganic phosphorus and potassium ions. Clinical trial of the regeneration systems was performed in patients with chronic renal failure on preparation for renal transplantation. The efficacy of the regeneration systems by elimination from the blood of metabolic products was not inferior to the standard hemodialysis system working in the discharge mode. The most promising method was that of electrochemical regeneration of the dialysis solution.

The effect of ultrafiltered dialysate on the cellular content of interleukin-1 receptor antagonist in patients on chronic hemodialysis.

We investigated the effect of dialysate ultrafiltration on the content of IL-1 receptor antagonist (IL-1Ra) in mononuclear cells (PBMC) as a marker of the inflammatory response. 11 patients on Cuprophan dialyzers were randomly assigned to treatment with standard bicarbonate dialysate first and then to ultrafiltered dialysate or the reverse order in a crossover design. In each treatment period (at least 4 weeks) weekly separations of PBMC were performed before the start of dialysis. Cellular content of IL-1Ra was determined in PBMC that were frozen immediately after separation; all values of IL-1Ra in each treatment period were averaged. The dialysate contained a median of 148 (range, 61-400) colony-forming units without dialysate filter; no bacterial growth was detected in ultrafiltered dialysate. The median endotoxin content was 80 pg/ml in nonfiltered dialysate; endotoxin was below 5 pg/ml in all ultrafiltered dialysate samples. Cellular content of IL-1Ra decreased in all but 1 patient with the use of ultrafiltered dialysate (mean +/- SEM: 1,467 +/- 113 pg/ml without dialysate filter vs. 1,166 +/- 104 pg/ml with filter, p = 0.016). The present study demonstrates that the bacterial contamination of the dialysate induces a systemic inflammatory response in hemodialysis patients.