ONLINE DIALYZER CLEARANCE USING CONDUCTIVITY

A method allowing non-invasive measurement of dialyser clearance in vi vo is described. Electrolyte concentration difference is measured by t wo conductivity sensors positioned up- and downstream of the dialyser in the dialysate path. From the conductivity differences measured at t wo different dialysate input concentrations and dialysate flow, electr olyte dialysance is calculated. The method takes recirculation effects into account and measures effective clearance rather than dialyser cl earance. Test results comparing on-line electrolyte clearance with blo od side clearance corrected for recirculation are consistent with this calculation. From clearance measured several times during dialysis an d time on dialysis, K.t can be calculated with an estimated accuracy o f +/- 10%. This method can be used to control the efficacy of each ind ividual treatment. The K.t goal can be derived from monthly two-pool k inetic modelling.