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Abstract: TH-PO332

Dialysate Potassium (K) Concentration and Total Dialysate Volume per Week During More Frequent Hemodialysis (MFHD) Determine Serum K After Transfer from In-Center Hemodialysis (ICHD): Model Predictions

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis

Authors

  • Leypoldt, J. Ken, Unaffiliated, San Clemente, California, United States
  • Weinhandl, Eric D., NxStage Medical, Inc., Victoria, Minnesota, United States
  • Kraus, Michael A., NxStage Medical, Inc, FISHERS, Indiana, United States
  • Collins, Allan J., NxStage Medical, Inc., Victoria, Minnesota, United States
Background

Low dialysate K concentrations during ICHD induce rapid intradialytic K removal and low postdialysis serum K concentrations; low dialysate K concentrations are also associated with a higher risk of sudden cardiac arrest. Using a mathematical model, we evaluated the effect of the MFHD prescription on predialysis serum K concentration (Kpre), postdialysis serum K concentration (Kpost) and intradialytic decrease in serum K concentration (ΔKintra) after transfer from ICHD.

Methods

The mathematical model was modified from one previously published (Agar et al, Hemodial Int 2015) by accounting for colonic K clearance. MFHD prescriptions included treatment frequencies of 3.5, 4, 5 and 6 treatments per week, dialysate volumes of 20-60 L/treatment and treatment durations of 120-240 min. Predialysis serum K concentration during ICHD was assumed between 4.0 and 5.5 mEq/L with a dialysate K concentration of 2 mEq/L.

Results

Model-predicted Kpre, Kpost, and ΔKintra during MFHD were primarily dependent on total dialysate volume per week (TDV) and dialysate K concentration. A schematic weekly profile of serum K during ICHD and MFHD is illustrated in the figure. The range of TDV on MFHD with dialysate K concentrations of 1 and 2 mEq/L required to decrease Kpre, Kpost and ΔKintra below that during ICHD are tabulated.

Conclusion

We conclude that transfer from ICHD to MFHD with low TDV can result in a lower Kpre without reducing Kpost or ΔKintra for dialysate K and MFHD prescriptions typically seen in clinical practice. As with any hemodialysis therapy, additional vigilance is required for patients persistently presenting with hypokalemia or those prescribed high TDV.

 TDV required to decrease K value below that during ICHD
MFHD Dialysate KKpreKpostΔKintra
1 mEq/L80-120 L120-200 L>360 L
2 mEq/L120-175 L300 L>360 L

Funding

  • Commercial Support