| Autor: |
Jaffrin, M., Jaffrin, M Y |
| Zdroj: |
Medical & Biological Engineering & Computing; 1981, Vol. 19 Issue 3, p321-327, 7p |
| Abstrakt: |
A theoretical model of mass transfer by ultrafiltration (u.f.) at large transmembranes pressures in parallel plate and hollow fibres haemofilters is presented. The analysis assumes that the maximum u.f. flow Q is limited by protein concentration polarisation and that the concentration boundary layer is thin. It takes into account the decrease of local blood flow along the membrane and therefore remains valid when the u.f. flow rate is a large fraction of the incoming blood flow Q. It is found that the ratio Q/Q increases nonlinearly with S/(Qd) where S is the membrane area and d the hydraulic diameter of the blood film. A parallel-plate haemofilter will have 20% more ultrafiltration than one of hollow fibre of the same membrane area and blood volume. However, if the two units have the same u.f. flow rate, the hollow fibre one will have the smaller blood volume. For a fibre type haemofilter at a given blood flow, Q is a function of the total fibre length and is independent of fibre diameter. By using a blood film thickness in the vicinity of 150 μ, adequate clearances (0·4Q) can be obtained with membranes areas of 0·6 to 0·7 m, significantly less than with present haemodialysers. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
Full text from SpringerLink