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Abstract: TH-PO336

The Effect of Dialysate Sodium Concentration on Intradialytic Hemodynamic Outcomes

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis


  • Skrtic, Marko, McMaster University, Hamilton, Ontario, Canada
  • Rabbat, Christian G., McMaster University, Hamilton, Ontario, Canada
  • Molnar, Amber O., McMaster University, Hamilton, Ontario, Canada
  • Brimble, K. Scott, McMaster University, Hamilton, Ontario, Canada
  • Walsh, Michael, McMaster University, Hamilton, Ontario, Canada

The effects of modest changes in dialysate sodium concentrations on inter-dialytic weight gain (IDWG), blood pressure and intra-dialytic hypotension (IDH) are uncertain. We studied the association between a change in sodium dialysate from 142 to 140 mmol/L and IDWG, blood pressure and IDH in in-centre hemodialysis patients.


The dialysate sodium concentration was changed from 142 mmol/L to 140 mmol/L in four dialysis units in Hamilton, Canada as part of a policy change. We assessed changes in IDWG, pre- and post- treatment systolic blood pressures, intra-dialytic change in systolic blood pressure, ultrafiltration volume, and frequency of intra-dialytic hypotension (intra-dialytic SBP < 90 mmHg) 8 weeks before and in two 8 week blocks after switching dialysate sodium from 142 to 140 mmol/L. All analyses were done using mixed-effects models in which patients were considered random intercepts and dialysate sodium was considered a fixed effect. All models were adjusted for age and sex.


Analyses included a total of 559 patients. Compared to the 8 weeks before changing the dialysate sodium, 8 to 16 weeks after the change to 140 mmol/L the mean ultrafiltration volume decreased by 0.11 L (95% confidence interval [CI] 0.07 to 0.12, p<0.001), the mean IDWG decreased by 0.10 kg (95% CI 0.02 to 0.18, p=0.01) and the mean pre-dialysis systolic blood pressure fell by 2.8 mmHg (95% CI 2.3 to 2.3, p<0.001). The odds of intra-dialytic hypotension were not significantly different (odds ratio 1.07, 95% CI 0.97 to 1.18, p=0.17).


Decreasing dialysate sodium from 142 to 140 mmol/L was associated with a reduced pre-dialysis SBP and IDWG without increasing the risk of IDH. Large randomized trials to understand the effects of modest changes in dialysate sodium on patient-important outcomes are needed to inform this fundamental component of dialysis care.