Paired Filtration-Dialysis (PFD): A Separate Convective-Diffusive System for Extracorporeal Blood Purification in Uraemic Patients
In haemodiafiltration (HDF) mass transfer of solutes through a membrane depends on both convection and diffusion. Diffusion has major importance in removing low-molecular weight solutes which would require a greater filtration flow if only convection were employed. Convection is essential for mass transfer of high-molecular weight solutes, since diffusive membrane permeability markedly decreases as molecular weight increases. The total clearance efficacy of HDF is less than the sum of the two single procedures since diffusion and convection do not take place subsequently but simultaneously and are mutually affected (1). In fact, simultaneous diffusion and convection with the same membrane determine convective clearance as low as contemporary diffusive clearance is high (2–4). The following equation, allowing calculation of convective clearance (Kconv), explains this fact.
KeywordsUric Acid Hollow Fibre Session Duration Uraemic Patient Blood Uric Acid
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- 1.Sprenger K.G.B., Stephan H., Kratz W., Huber K., Franz H.E., 1985, Optimizing of hemodiafiltration with modern membranes? Contr. Nephrol., 46: 43 Karger, Basel.Google Scholar
- 2.Ghezzi P.M., Frigato G.,. Fantini G.F., Dutto A., Meinero S., Cento G., Marazzi F., d’Andria V., Grivet V., 1983, Theoretical model and first clinical results of the paired filtration-dialysis (PFD). Life Support System, Proceedings of Xth annual Meeting ESAO, Bologna, 15–17 September, 1983, W.B. Saunders Publ., London, p. 271.Google Scholar
- 3.Ghezzi P.M., Grivet V., Nigrelli S., Meinero S., Marazzi F., Canepari G., Cento G., Gervasio R., Botella J., 1985, A new dialytic strategy (paired filtration-dialysis) using a polysulphone membrane. Malta Meeting on Clinical Aspects of Polysulphone Membranes, Malta, October 24–27 in press.Google Scholar
- 4.Gupta B.B., Jaffrin M.Y., 1984, In vitro study of combined convection- diffusion mass transfer in hemodialysers. Int.J.Art.Org., 5: 263.Google Scholar
- 7.Floege J., Granolleras C., Deschodt G., Branger B., Oules R., Shaldon S., Koch K.M., 1986, Beta2-microglobulin kinetics during hemodialysis and hemofiltration. XXIIIrd Congress of EDTA-European Renal Association, June 29-July 3, Budapest, Abstracts, p.122.Google Scholar
- 8.Zingraff J., Beyne P., Bardin T., Touam M., Uzan M., Man N.K., Drueke T., 1986, Dialysis amyloidosis and plasma beta2-microqlobulin. XXIIIrd Congress of EDTA-European Renal Association, June 29-July 3, Budapest, Abstracts, p. 162.Google Scholar