The Donnan equilibrium is still valid in high-volume HDF.

Clinical studies have shown that hemodiafiltration reduces morbidity and mortality of dialysis patients compared to hemodialysis alone. This is attributed to its superior middle molecule clearance compared to standard hemodialysis. However, doubts arose as to whether a high convective flux through the dialyzer membrane has an influence on the equilibrium concentration of small ions, especially that of sodium.

Automated individualization of dialysate sodium concentration reduces intradialytic plasma sodium changes in hemodialysis.

In standard care, hemodialysis patients are often treated with a center-specific fixed dialysate sodium concentration, potentially resulting in diffusive sodium changes for patients with plasma sodium concentrations below or above this level. While diffusive sodium load may be associated with thirst and higher interdialytic weight gain, excessive diffusive sodium removal may cause intradialytic symptoms. In contrast, the new hemodialysis machine option "Na control" provides automated individualization of dialysate sodium during treatment with the aim to reduce such intradialytic sodium changes without the need to determine the plasma sodium concentration.

Zero Diffusive Sodium Balance in Hemodialysis Provided by an Algorithm-Based Electrolyte Balancing Controller: A Proof of Principle Clinical Study.

Restoring and controlling fluid volume homeostasis is still a challenge in contemporary end-stage kidney disease patients treated by intermittent hemodialysis (HD) or hemodiafiltration (HDF). This primary target is achieved by ultrafiltration (dry weight probing) and control of intradialytic sodium transfer (dialysate-plasma Na gradient). The latter task is mostly ignored in clinical practice by applying a dialysate sodium prescription uniform for all patients of the dialysis center but unaligned to individual plasma sodium levels.

Ionic dialysance measurement is urea distribution volume dependent: a new approach to better results.

Conductivity (CD)-based dialysance measurements precisely match urea dialysance with <5% difference. For measurement, a CD step-profile is applied by increasing dialysate inlet CD at time t0 for 10% above baseline and lasting for 2-5 min until t1, followed by a decrease to -4% until t2 and a final return to baseline, meanwhile recording dialysate CD at filter inlet (cdi) and outlet (cdo), dialysate flow (Qd), and ultrafiltration (UF)-rate (Qf). Electrolytic dialysance (KeCn) is calculated by KeCnI,J = (1 -[cdoI-cdoJ]/[cdiI-cdiJ])(Qd+Qf) with time index I not = J.