Abstract
As a trial to clean dialystes thoroughly, an EF-01 filter (PEPA membrane) installed at the dialysate inlet of the bedside console was used, in addition t the usual procedure for cleaning hemialysis (HD) equipment and supply channels. As a result, the endotoxin (ET) concentration at the outlet of the filter was reduced to below detection level. In the joint of the O-ring coupler connected to the dialyzer, however, an abnormally high ET concentration was observed. When this coupler was used the dialysate in the dialyzer was found to be contaminated with bacteria such as Pseudomonas sp even immediately after the apparatus was automatically washed. Culture of the O-ring bacteria found in the coupler, which was carried out after the coupler was sterilized by soaking it in NaOCl, suggested that this contamination was caused by incomplete sterilization of the inside of the O-ring. Therefore, we investigated the contamination of the dialysate in the dialyzer by using a silicone coupler, which has no O-ring. In the first HD, contamination by bacteria and ET was not observed. However, in the second and third HD carried out on the same day, bacterial contamination was observed. This was believed to be caused by a bypass connector for linking dialysate tubings, not in treatment. In the future, it will be necessary to clean and disinfect coupler joints in a simpler way.
