Sodium and body fluid homeostasis in profiling hemodialysis treatment

Acute adverse side-effects of hemodialysis such as hypotension, muscle cramps, osmotic imbalance and thirst are induced by the interference with fluid and electrolyte balance occurring during treatment. Changes in osmolarity due to alterations of plasma sodium concentration during hemodialysis strongly influence fluid distribution between extracellular and intracellular fluid volume. Increased sodium dialysate concentration induces fluid shift from the intracellular to the extracellular compartment. This shift leads to a more efficient ultrafiltration by increasing plasma refilling volume but also to an increased thirst. Treatment of hypotension, cramps and nausea with hypertonic saline solution leads also to a considerable retention of sodium. Profiling hemodialysis consists in deliberately changing ultrafiltration and dialysate sodium in order to combine an efficient ultrafiltration with a balanced sodium handling and to prevent side-effects during treatment. Continuous measurement and control of blood volume seems to be the best method to prevent hypotensive episodes. Profiling of sodium should not be the cause of a positive sodium balance. The clinical benefits of sodium profiling to the patients have still to be proven.