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Theoretical Basis and Experimental Verification of the Impact of Ultrafiltration on Dialyzer Clearance
Author(s) -
Waniewski Jacek,
Werynski Andrzej,
Ahrenholz Peter,
Lucjanek Piotr,
Judycki Wladyslaw,
Esther Gisela
Publication year - 1991
Publication title -
artificial organs
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.684
H-Index - 76
eISSN - 1525-1594
pISSN - 0160-564X
DOI - 10.1111/j.1525-1594.1991.tb00763.x
Subject(s) - ultrafiltration (renal) , chemistry , thermodynamics , chromatography , physics
Dialyzer clearance K is usually presented as K = K O + Tr Q u , where Q u is ultrafiltration rate, K 0 is clearance for Q u – 0, and T r is transmittance coefficient. Although a simple and accurate mathematical description of K o is widely used, only a somewhat inaccurate formula for T r that predicts a linear relationship between T r and K o has been proposed before. In this study the detailed investigation of T r using a one–dimensional theory of a dialyzer is presented. In general, the application of a one–dimensional theory requires sophisticated numerical methods, but for small and middle molecular weight solutes an analytical formula for K can be derived. T r predicted by the developed theory in comparison to T r predicted by the previous linear formula is higher for small molecular weight solutes and lower for middle and large molecular weight solutes. These theoretical results were confirmed in experiments carried out in vitro for hollow–fiber dialyzers and small molecular weight solutes (urea, creatinine, sodium, TcO 4 ) as well as middle molecular weight solutes (vitamin B 12 ).