Conservation of Mass: An Important Tool in Renal Research

Abstract

The dialytic treatment of end-stage renal disease (ESRD) patients is based on control of solute concentrations and management of fluid volume. The application of the principal of conservation of mass, or mass balance, is fundamental to the study of such treatment and can be extended to chronic kidney disease (CKD) in general. This review discusses the development and use of mass conservation and transport concepts, incorporated into mathematical models. These concepts, which can be applied to a wide range of solutes of interest, represent a powerful tool for quantitatively guided studies of dialysis issues currently and into the future. Incorporating these quantitative concepts in future investigations is key to achieving positive control of known solutes, and in the analysis of such studies; to relate future research to known results of prior studies; and to help in the understanding of the obligatory physiological perturbations that result from dialysis therapy.

Effect of Treatment Duration and Frequency on Uremic Solute Kinetics, Clearances and Concentrations

“…The current discussion is based on the assumption that alterations in dialysis therapies to improve patient outcomes can be individualized and do so because they lower the concentration of uremic solutes in patient body fluids, i.e., that the effects of uremia are concentration‐dependent . This concept has been termed “axiomatic” in considerations of uremia and is based on an analogy to the toxicological principles of drug therapy, where the safety and efficacy of drugs are based on their concentration at target organs . The knowledge gap in the case of uremia, however, is that neither the most important toxins nor the target organs are precisely known.…”