FP527
AUTOMATED INDIVIDUALIZATION OF DIALYSATE SODIUM CONCENTRATION REDUCES INTRADIALYTIC PLASMA SODIUM CHANGES IN HEMODIALYSIS Free

INTRODUCTION: In hemodialysis practice a center-specific fixed dialysate sodium concentration is often applied. Differences between this concentration and plasma sodium concentration may result in diffusive sodium changes. Sodium load may be associated with thirst and higher interdialytic weight gain, whereas excessive diffusive sodium removal may cause intradialytic symptoms. The new option “sodium control” in the current generation of the hemodialysis machine by Fresenius Medical Care, Germany 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.

METHODS: This proof-of-principle study on sodium control was designed as a monocentric randomized controlled cross-over trial: 32 patients with residual diuresis of ≤ 1,000 mL/day were enrolled to be treated by high-volume post-dilution hemodiafiltration for two weeks each with “sodium control” (individually and automatically adjusted dialysate sodium concentration) versus “standard fixed sodium” (fixed dialysate sodium 138 mmol/L), in randomized order. Pre- and post-dialytic plasma sodium concentrations were determined at bedside by direct potentiometry. The study hypothesis consisted of two components: to confirm mean plasma sodium change between the start and end of the treatment being within ±1.0 mmol/L for sodium-controlled treatments, and to achieve a lower variability of the plasma sodium changes for “sodium control” than for “standard fixed sodium” treatments.

RESULTS: 358 treatments (“standard fixed sodium”: 181, “sodium control”: 177) were analyzed. The estimate for the mean plasma sodium change was -0.53 mmol/L (95% confidence interval: [-1.03; -0.04] mmol/L) for “sodium control” treatments and -0.98 mmol/L (95% confidence interval: [-1.77; -0.20] mmol/L) for “standard fixed sodium” treatments. The standard deviation of the plasma sodium changes was 1.35 mmol/L for “sodium control” vs. 2.14 mmol/L for “standard fixed sodium” treatments (p=0.0008).

Whereas the 95% confidence interval for the estimate for the mean plasma sodium change during “sodium control” treatments marginally overlapped the lower border of the predefined margin ±1.0 mmol/L, the variability of intradialytic plasma sodium changes was significantly lower during “sodium control” versus “standard fixed sodium” treatments.

CONCLUSIONS: Automated dialysate sodium individualization by “sodium control” approaches isonatremic dialysis in the clinical setting, and may provide the instrumental basis to an improved management of intradialytic sodium changes.