Prescribing Dialysate Sodium in Maintenance Hemodialysis Patients: What Can Conductivity Monitoring Contribute?

BACKGROUND: Sodium management during hemodialysis session is based on the dialysate sodium (NaD) prescription by the physician. However, the conflicting results of studies concerning the relationship between NaD and mortality, and the sometimes significant difference between the NaD prescribed and its actual value, are barriers to issuing on the optimal NaD value. In the absence of any rational justification for preferring high or low dialysate sodium, prescribing NaD remains empirical and quite intuitive.

SUMMARY: From a clinical perspective, several arguments suggest prescribing the change in natremia (ΔNa) to be achieved at the end of the dialysis session rather than the NaD value. Conductivity monitoring allows to calculate an online estimate (NaCond) of natremia and makes the hemodialysis monitor able to automatically adjust NaD to achieve a NaCond target. From a technical standpoint, prescribing a NaCond-change target (ΔNaCond) rather than a NaCond target has the major advantage that the ΔNaCond value obtained at the end of the session may be unaffected by any lack of accuracy in the NaD value. Key-Messages: Prescribing a target change (ΔNa) in natremia appears to be more rational and clinically relevant than prescribing a dialysate sodium. Conductivity monitoring makes it easier to implement this prescription in everyday clinical practice.