Short-time hemodiafiltration using polymethylmethacrylate hemodiafilter

Three times 3 hr/wk hemodiafiltration (simultaneous hemofiltration and dialysis: HDF) using Toray HDF system has been carried out on 4 patients. Filters used were Toray Filtryzers (membrane: polymethylmethacrylate, surface area 1.15 M2) with a dialysate flow of 500 ml/min. Nine to 10 L of body fluid was removed and 7-8 L of substitution fluid was reinfused distal to the filter (postdilution). Short-time HDF was favorable accepted by the patients. Blood pressure was stable, and disequilibrium syndrome negligible. Clinical courses as well as laboratory findings of the patients were satisfactory. The reduction rate of middle to larger molecules was 20 to 100% higher compared to conventional HD as measured by chromatogram. Loss of amino acids was about 3 gm/treatment. Reduction of hormones was negligible and no depletion syndrome was observed throughout the observation period up to 10 mos. Acidosis was corrected within 3-4 hrs. Elevated blood concentration of lactate and acetate gradually decreased to a pretreatment level within 2-3 hrs after termination of the procedure. Removal of middle molecules by HDF, in addition to removal of small molecules by conventional hemodialysis, is considered to be the treatment of choice for uremic patients.