[Use of dialysate conductivity to obtain neutral sodium balance in chronic hemodialysis patients].
In order to assure a zero sodium balance in hemodialysis patients, attaining 'constant' values of total body water and plasma water sodium concentration at the end of each dialysis session is a basic pre-requisite. This is achieved by matching the ultrafiltration to the inter-dialytic weight gain and by individualizing dialysate sodium concentration at each dialysis session by making use of a kinetic model. Clinical results suggest that the single pool variable volume sodium kinetic model allows the targeted end-dialysis plasma water sodium concentration to be obtained. Nevertheless, this model is not suitable for routine clinical application, because of difficulties in the real-time determination of initial plasma water sodium concentration and 'effective' sodium dialysance. Measuring dialysate conductivity at the inlet and outlet ports of the dialyzer allows the estimation of sodium transfer during dialysis, if the function of concentration versus conductivity is known. If sodium transfer is measured at two different inlet dialysate conductivities, it is possible to determine ionic dialysance and systemic plasma water conductivity, which can be used routinely to apply the single pool sodium kinetic model. Given that ionic dialysance and plasma water conductivity can be measured easily repeatedly and inexpensively at each dialysis session without the need for blood sampling or laboratory determinations, it can be expected that conductivity kinetic models will soon become a part of everyday clinical practice.
Di Filippo
S
S
Divisione di Nefrologia e Dialisi, Ospedale A. Manzoni, Lecco. nefrologia@ospedale.lecco.it
Manzoni
C
C
Pozzoni
P
P
Locatelli
F
F
D004553:Electric Conductivity; D006801:Humans; D007676:Kidney Failure, Chronic / Q000378:metabolism / Q000628:therapy; D006435:Renal Dialysis / Q000379:methods*; D012964:Sodium / Q000378:metabolism*; D014882:Water-Electrolyte Balance
D012964:Sodium