A note on the representation of the performance of hemodialyzers.

The performance of hemodialyzers was expressed schematically using three dimensionless quantities. Compared with the usual representation in which the dialysance is plotted against the blood flow rate for each of the solutes of interest, this expression is considered to have the following advantages: (1) the function of a dialyzer to remove different solutes can be expressed by a single curve, (2) the effect of changing the membrane area, its permeability, and the flow rates on the performance can easily be understood, and (3) the effect of changing the blood flow rate on the ratio of the transport efficiency of two or more kinds of solutes can be evaluated. An estimate of the overall mass transfer coefficient is the only procedure necessary to move from the usual to the present expression. These analyses were applied to the performance of a commercial hemodialyzer, and it was verified that this representation could denote its operation fairly well.