Relevance of the conductivity kinetic model in the control of sodium pool

Changes in the body sodium poor caused by dialytic treatment have very impo rtant clinical implications, mainly in terms of intradialytic cardiovascula r instability and interdialytic hyperhydration and hypertension with long-t erm cardiac hypertrophy and dilation. A kinetic model could be helpful in o rder to define the dialysate sodium concentration needed to match intradial ytic hydrosodium removal with interdialytic sodium and water intake, but un fortunately, none of the sodium kinetic models are suitable for routine cli nical application. Two conductivity kinetic models (one for hemodialysis an d one for paired filtration dialysis) have been developed on the basis of t he linear relationship between the sodium content and conductivity of every saline solution and plasma water and according to basic theory for ionic d ialysance determination. These models make it possible to know at the start of each session the dialysate conductivity needed to obtain the desired fi nal plasma water conductivity or to know the latter when the former is know n. Clinical evaluations showed that conductivity kinetic models are very pr ecise and accurate and may be used instead of sodium kinetic models. Furthe rmore, they are suitable for routine use because they do not require brood sampling or laboratory determinations. Clinical application of the conducti vity kinetic model has shown that the reduced variability of end-dialysis p lasma water conductivity obtained when using the model to identify dialysat e conductivity significantly reduces cardiovascular instability, even witho ut any changes in average sodium removal. Given that ionic dialysance can b e easily, inexpensively, and repeatedly measured at each dialysis session, it seems realistic to expect that conductivity kinetic modeling will soon b ecome a part of everyday clinical practice.