Theoretical description of mass transport in medical membrane devices.

The application of the one-dimensional theory of mass transport to the derivation of mathematical formulas for clearances of a variety of membrane mass exchangers, namely hemodialyzers, hemofilters, plasma separators, and the cascade filtration procedure, has been reviewed. The applied theory predicts that clearances depend approximately on fluid inlet flow rates but not on concentrations, and with constant fluid flow rates, clearances are constant. Also, the application of device clearance in kinetic modeling has been discussed.