Abstract
Hemodialysis membranes act to remove accumulated uremic toxins, excess ions and water from the patient via the dialysate, and to supply from the dialysate those ions that are insufficient. In evaluating dialysis membranes, the most important factors are diffusive and hydraulic permeability. It is primarily through diffusion, resulting from the difference in concentration between the blood and the dialysate, that the toxins and ions pass through the dialysis membrane. Thus if diffusive and hydraulic permeability can be measured, it becomes possible to evaluate dialysis membranes.
Basically, the diffusive permeability can be found from data on differences in concentration and on the solute flux obtained when filtration flux is set to zero. Techniques for the measurement of the diffusive and hydraulic permeability of flat dialysis membranes are already well established and measurement is comparatively simple, but this is not the case for hollow-fiber dialysis membranes.
To find the hydraulic permeability of a dialysis membrane, the filtrate volume obtained at a certain trnsmembrane pressure is measured over a given period of time. If a dialyzer is used, the (static) pressure of the fluid along the length of the flow channel changes, so that it is technically difficult to determine transmembrane pressure accurately while the blood and dialyste are flowing. Thus in measuring the filtration coefficient available method include the dead-end or complete filtration method.
This paper describes dialysis membrane and dialyzer for blood purification, solute transport mechanism of membrane and technical evaluation of dialysis membrane. The next generation of artificial kidney is lastly viewed.
