#6780 EFFECTS OF ISONATREMIC DIALYSIS ON INTERDIALYTIC WEIGHT GAIN RELYING ON AN AUTOMATED SODIUM CONTROL ALGORITHM: INTERIM ANALYSIS OF DISON-IRC STUDY
Authors: Morena Marion , Chalabi Lotfi , Bachelet Thomas , Bosc Jean-Yves , Souweine Jean-Sébastien , Rodriguez Annie , Bargnoux Anne-Sophie , Cuny-Merle Mélodie , Saidani Farid , Hebibi El Hedia , Cornillac Laure , Attaf David , Canaud Bernard , Cristol Jean-Paul 
Published: June 2023

Abstract

Background and Aims
Sodium (Na) is a major determinant of extracellular fluid volume and osmolarity homeostasis. Chronic fluid overload (FO) is present in 30 to 50% of hemodialysis patients (HD). HD patients are mostly treated with fixed dialysate Na concentration irrespective of plasma Na concentration. This fixed approach tends to displace patient's osmolar set point and stimulates thirst and weight gain. An automated personalized dialysate Na alignment to patient's natremia to avoid unwanted diffusive Na gain and tonicity change induced by HD seems preferable. Several studies exploring individualized dialysate Na prescription have reported inconsistent results. In this prospective interventional multicenter study, we aimed to explore the impact of dialysate Na individualization through isonatremic HD on interdialytic weight gain (IDWG) (primary outcome) and dialytic HD-related symptoms (secondary outcome). For this purpose, we have used the automated “Na Control” option for adjusting dialysate Na to minimize dialysate-plasma sodium gradient and deliver an isonatremic dialysis.

Method
This is a longitudinal study comparing 2 periods: Period-1 = observational phase (2 months) → Period-2 = isonatremic phase by activation of “Na Control” in isonatremic mode (2 months) → comparison of IDWG between both periods. The embedded “sodium control” option in HD machine was used in all cases of Period-2 to actively align dialysate sodium concentration to natremia and quantify net sodium mass transfer. Results are expressed as mean±SD or median [25th-75th].

Results
We present preliminary results obtained through 6 dialysis facilities including 51 patients, 33 (64.7%) females, 75 [65-81] years old, dry weight 71.9 [60.5-78.0] kg. Main findings are as follows: Firstly, an excellent agreement was observed between plasma Na concentrations, measured (laboratory) and estimated (machine) from HD monitor (mean difference before dialysis: 0.05, after dialysis: 0.62); Secondly, plasma Na estimated was as follows: before dialysis plasma Na (137.6 [136.2-139.0] vs 137.2 [136.0-139.3] and after dialysis plasma Na (139.0 [137.6-139.7] vs 137.1 [135.7-138.9]) in Period-1 and Period-2 respectively; Thirdly, the primary outcome (IDWG) as well as the diffusive Na balance were significantly reduced by isonatremic dialysis condition (IDWG: 2.17±0.92 versus 1.95±0.86 kg, p&lt;0,0001; diffusive Na balance (3.9 [1.9-5.1] versus 0.7 [0.0-2.7] g of Na, p&lt;0.0001).

Conclusion
Isonatremic dialysis condition automatically driven by “Na control” embedded In HD monitor was confirmed safe and easily implemented in clinical workflow. In addition, these preliminary results show that isonatremic dialysis improved dialysis patient perception and significantly reduced IDWG.