Increasing the Dialysate Sodium Concentration Based on Serum Sodium Concentrations Exacerbates Weight Gain and Thirst in Hemodialysis Patients

Abstract

Most dialysis centers adopt a standard dialysate sodium prescription. While pre-hemodialysis (HD) serum sodium levels remain relatively constant in each individual patient on chronic HD, these levels can vary between different patients. Therefore, a single dialysate sodium prescription may not be appropriate for all patients. Nineteen stable patients on maintenance HD were dialyzed for 9 HD sessions with their current dialysis solutions, followed by another 9 sessions using individualized prescriptions created by aligning dialysate sodium levels to each patient's serum sodium concentration. Patients were divided into 2 groups according to whether the average pre-HD serum sodium concentration was higher than (higher serum sodium group, n = 13) or equal to (equal sodium group, n = 5) the standard dialysate sodium concentration. Pre-HD serum sodium levels remained constant during entire study period in both groups. In higher serum sodium group, interdialytic weight gain increased after implementation of the sodium alignment (2.0 ± 0.3 kg vs. 2.3 ± 0.4 kg; P = 0.008). Thirst scores also increased in patients whose dialysate sodium was increased by 4 mmol/L (n = 7) (6.4 ± 1.5 vs. 7.6 ± 1.5, P = 0.015). There were no significant changes in blood pressure and intradialytic complications. In equal sodium group, significant differences were not observed in any parameters. Our results suggest that alignment of dialysate sodium levels to each patient's serum sodium concentration is of little benefit in hemodynamically stable patients who have pre-HD serum sodium concentrations higher than dialysate sodium concentration.

Is increased subjective thirst associated with greater interdialytic weight gains, extracellular fluid and dietary sodium intake?

“…Previous studies have demonstrated an effect of using higher dialysate sodium concentrations and a positive dialysate to sodium gradient on increasing IDWGs 25,26 . Although we found no association between dialysate sodium concentration or the dialysate to sodium gradient and either thirst scores or IDWGs, but this may reflect our choice of lower dialysate sodium concentrations and much smaller gradients used compared to these earlier studies.…”

Prevalence and associated variables of post‐dialysis fatigue: Results of a prospective multicentre study

“…Indeed, Dreisbach et al did not find significant differences in intradialytic osmolarity reduction between patients with and without PDF. In addition, studies that have compared high‐ and low‐sodium baths have led to conflicting results . Rayner et al found that longer recovery time after dialysis was associated with greater intradialytic weight loss, longer dialysis session duration, and dialysate sodium concentration < 140 mEq/L.…”

“…In addition, studies that have compared high-and low-sodium baths have led to conflicting results. [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] Rayner et al 19 found that longer recovery time after dialysis was associated with greater intradialytic weight loss, longer dialysis session duration, and dialysate sodium concentration < 140 mEq/L. They also showed that both slow and fast ultrafiltration rates (<5 and >15 mL/min, respectively) were associated with a shorter recovery time compared with an ultrafiltration rate of 5-15 mL/min.…”

It is Time to Individualize the Dialysate Sodium Prescription

“…studied 19 patients treated with a Na + D matching their serum sodium level. Unlike patients in most of these studies, 13 of these patients had serum sodium higher than the standard Na + D. On implementation of sodium alignment, their thirst scores and IDWG increased, with no effect on blood pressure or intradialytic complications .…”