[The different modalities of isonatric hemodialysis]

Setting dialysate sodium allows to adequately adjust sodium balance and plasma sodium at the end of dialysis session. In accordance with the set-point theory based on the concept of restoring cellular hydration, an adequate target for plasma sodium at the end of the session could be the value of predialysis plasma sodium concentration (isonatric hemodialysis). Some recently available dialysis monitors provide an on-line value of plasma-water conductivity usually converted in on-line natremia. There are different modalities of isonatric hemodialysis depending on whether the online value of natremia is used or not. By reviewing the few studies concerning the isonatric hemodialysis, it seems logical to set a target of postdialysis on-line natremia (or plasma-water conductivity) slightly lower than its predialysis value. However this strategy requires specifically designed software not yet available in clinical routine.