Choice of dialyzers for HDF

Commercial dialyzers were investigated both in vivo and in vitro for a better selection of dialyzers for hemodiafiltration (HDF) therapy. In in vivo online HDF, since a reduction rate of α(1)-microglobulin (α(1)-MG) was determined by the amount of albumin loss regardless of blood flow rate (Q(B)), ultrafiltration rate (Q(F)), and the performance of dialyzer, there is no preference for choice of dialyzers to remove α(1)-MG except for albumin sieving. It was clinically verified that albumin leakage mainly occurred in the first 60 min of treatment even in HD with a polysulfone dialyzer. Ultrafiltration may be more carefully started in order to reduce albumin loss. In an in vitro study, the sieving coefficient for albumin took a peak value at the beginning of the experiment in all polysulfone membrane dialyzers, which corresponded well with the clinical results stated above. Although polymethylmethacrylate membrane dialyzers allowed to penetrate only a limited amount of albumin, they could adsorb a bigger amount of albumin than that penetrated. If dialyzers are used under high Q(B), post-dilution may be preferred because pre-dilution should increase the apparent blood flow rate as well as blood pressure at the inlet. If dialyzers are used under relatively low Q(B), either one of two dilution methods can be applied; however, with pre-dilution it may be easier to control the loss of albumin than with the post-dilution technique. In other words, I would be recommended to employ less albumin-leakage dialyzers when a post-dilution HDF is performed with a large amount of fluid exchange.