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Kidney Week

Abstract: FR-PO492

Optimizing Serum Total Carbon Dioxide Concentration During More Frequent Hemodialysis Using Low Dialysate Flow and Lactate Dialysate

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis


  • Leypoldt, J. Ken, Nalecz Institute of Biocybernetics and Biomedical Engineering Polish Academy of Sciences, Warsaw, Poland
  • Kraus, Michael A., NxStage Medical, Inc, Fishers, Indiana, United States
  • Collins, Allan J., NxStage Medical, Inc., Lawrence, Massachusetts, United States

There have been few studies to determine the optimal dialysate lactate concentration ([lactate]) during more frequent hemodialysis (MFHD) at low dialysate flow rates using the NxStage System One dialysis delivery system to achieve a predialysis serum total carbon dioxide concentration ([TCO2]) of 22-26 mEq/L. We used clinical data in patients who transferred from in-center, thrice weekly hemodialysis (ICHD) using bicarbonate dialysate to 6 times per week hemodialysis using lactate dialysate during the FREEDOM Study and the H+ mobilization model (Sargent et al, Semin Dial 31:468-78, 2018) to calculate the effect of dialysate [lactate] during MFHD on [TCO2] after transfer from ICHD.


The H+ mobilization model was first used to simulate ICHD treatments using dialysate bicarbonate concentration ([bicarbonate]) of 34, 37 & 40 mEq/L at [TCO2] of 20, 22 & 24 mEq/L to determine a weekly acid generation rate. Assuming a constant weekly acid generation rate, patients were assumed transferred to MFHD with treatment (Tx) frequencies of 4, 5 & 6 times per week with dialysate volume per Tx &Tx times of 40 L & 210 min, 30 L & 180 min, and 25 L & 170 min, respectively. Blood flow rate was assumed as 450 mL/min and dialysate [lactate] as either 40 or 45 mEq/L during MFHD.


Summary results are tabulated. After transfer from ICHD, [TCO2] during MFHD increased when using a dialysate [lactate] of 45 mEq/L but not when using a dialysate [lactate] of 40 mEq/L. [TCO2] during MFHD was higher at higher [TCO2] during ICHD. Calculated results were predominantly dependent on the weekly dialysate volume (150-160 L/wk) and relatively independent of Tx frequency.


KDOQI guidelines suggest that [TCO2] should be ≥22 mEq/L; therefore, these results suggest that patients transferring from ICHD with [TCO2] ≤24 mEq/L should initially be prescribed a dialysate [lactate] of 45 mEq/L when using 150-160 L/wk of dialysate volume during MFHD .

[TCO2] During MFHD (mEq/L)
 Dialysate [Lactate] of 40 mEq/LDialysate [Lactate] of 45 mEq/L
[TCO2] During ICHD4 Tx/wk5 Tx/wk6 Tx/wk4 Tx/wk5 Tx/wk6 Tx/wk
20 mEq/L181920222324
22 mEq/L202122242425
24 mEq/L222223252627

All values averaged for dialysate [bicarbonate] during ICHD of 34, 37 and 40 mEq/L; the standard deviation of all values was 1 mEq/L.


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