Abstract
A thinner regenerated cellulose membrane is used in new hemodialyzers with longer outer shells. One of them was compared with the old type model, which has approximately the same surface area, from the aspect of solute and water removal capacity.
No significant differences were found in urea and creatinine clearances between the two models; however, the new model has a little higher clearance tendency depending on the dialysate flow rate in both solutes.
In uric acid and inorganic phosphate, the new model has not only a higher clearance but also a higher dependency of the clearance on the dialysate flow rate.
According to the relationship between clearance and the molecular weights of the small solutes, a thinner dialysis membrane seemed to be advantageous for removing larger solutes.
A thinner membrane also makes it possible to remove a larger amount of water. In clinical therapy, the transmembrane pressure (IMP) is set in accordance with the pseudo ultrafiltration coefficient (UFR/Pps) of the dialyzer. The real TMP decreases as the pressure drop increases with the dialysate flow rate. UFR/Pps must be controlled by such a means for clinical use of dialyzers.
