Kashiwagi Tetsuya, Sato Kazuto, Kawakami Seiko, Kiyomoto Masayoshi, Takei Hiroyuki, Suzuki Tatsuya, Genei Hirokazu, Nakata Hiroaki, Iino Yasuhiko, Katayama Yasuo
Department of Neurological, Nephrological and Rheumatological Science, Graduate School of Medicine, Nippon Medical School, Japan.
J Nippon Med Sch. 2011;78(4):214-23. doi: 10.1272/jnms.78.214.
Hemodialysis is a method for removing uremic toxins and water directly from the blood into a dialysis fluid through an artificial semipermeable membrane called a dialyzer. The ability of the dialyzer to remove uremic toxins has steadily improved, but the likelihood has also increased that bioactive substances, such as bacterial endotoxin (ET) fragments, can be transferred from the dialysis fluid into the patient's blood through the phenomena of back-diffusion and back-filtration in the dialyzer. Therefore, further efforts to improve the quality of water are required. In 2008, the Committee of Scientific Academy of the Japanese Society for Dialysis Therapy presented its new recommendations for the quality standards of dialysis fluid, but achieving and maintaining these standard values would seem difficult without installing an ET-retentive filter (ETRF). In the present study, we evaluated whether the standards for ultrapure dialysis fluid of the Japanese Society for Dialysis Therapy can be achieved and maintained by installing 3 types of ETRF for a period of 12 months.
To evaluate the quality of dialysis fluid, ET values were measured with nephelometry, and viable cell counts were determined with the membrane filter method. Changes in the basic performance of the ETRFs were evaluated by measuring their water permeability, ET-retentive capacity, and hollow-fiber membrane intensity. Moreover, the hollow-fiber membrane surfaces of the ETRFs were observed with scanning electron microscopy, and the elements of the adherent substances were identified by means of energy dispersive X-ray spectrometry.
The ET concentrations were less than the limit of detection during the evaluation period for samples obtained at post-ETRF sites. The viable cell counts for pre-ETRF sites were approximately 10 colony-forming units/mL. However, colonies had not formed in samples obtained from the post-ETRF sites. The substances adhering to hollow fibers included the silicon from the dialysate powder, the iron from the fluid path, and the elements derived from stainless steel. Scanning electron microscopy of the ETRF hollow fibers showed no substances except the hollow fibers and the elements derived from the dialysis fluid.
Installation of an ETRF is useful for achieving and maintaining the quality standards for ultrapure dialysis fluid and for preventing the entry into the blood of ETs, viable cells, and such substances as silicon and metals.
血液透析是一种通过名为透析器的人工半透膜，将尿毒症毒素和水分直接从血液中清除到透析液中的方法。透析器清除尿毒症毒素的能力在不断提高，但生物活性物质（如细菌内毒素（ET）片段）通过透析器中的反向扩散和反向过滤现象从透析液转移到患者血液中的可能性也增加了。因此，需要进一步努力提高水的质量。2008年，日本透析治疗学会科学委员会提出了透析液质量标准的新建议，但如果不安装ET保留过滤器（ETRF），似乎很难达到并维持这些标准值。在本研究中，我们评估了安装3种类型的ETRF 12个月能否达到并维持日本透析治疗学会的超纯透析液标准。
为评估透析液质量，采用比浊法测量ET值，采用膜过滤法测定活菌数。通过测量ETRF的水渗透性、ET保留能力和中空纤维膜强度，评估ETRF基本性能的变化。此外，用扫描电子显微镜观察ETRF的中空纤维膜表面，并用能量色散X射线光谱法鉴定附着物质的元素。
在评估期间，从ETRF后位点获得的样品中ET浓度低于检测限。ETRF前位点的活菌数约为10个菌落形成单位/毫升。然而，从ETRF后位点获得的样品中未形成菌落。附着在中空纤维上的物质包括透析液粉末中的硅、流体路径中的铁以及不锈钢中的元素。ETRF中空纤维的扫描电子显微镜显示，除中空纤维和透析液中的元素外，没有其他物质。
安装ETRF有助于达到并维持超纯透析液的质量标准，并防止ET、活菌以及硅和金属等物质进入血液。
