Examples of Urea Modeling

Abstract

The following examples illustrate typical applications of urea modeling. Clinical “cases” represented by all data pertinent to urea modeling, such as dialyzer clearance and BUN, are presented with variables calculated from different models. Sometimes the technical conditions are exaggerated to emphasize a point, such as the effect of fluid gain. The cases illustrate practical clinical problems and how urea modeling is used to solve them. An “ideal” patient is presented first, followed by selected modifications to demonstrate the effect of residual clearance, schedule variations, large weight changes, dietary noncompliance, high-flux dialysis, errors in measurement of dialyzer clearance, and variations in patient size. All data are displayed in tables, so no calculator or computer is required to examine the cases in this chapter. In the tables, significant changes due to manipulation of patient or dialysis variables are underlined. Explanations for the underlined changes are found in the text.