Kidney Week

Abstract: TH-PO1213

How to Optimise Dialysis Adequacy in Paediatric Patients While Limiting Water Consumption

Session Information

• Pediatric Nephrology: CV Health, CKD, AKI, Dialysis, Transplantation, and Health Services Research
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Pediatric Nephrology

• 1800 Pediatric Nephrology

Authors

• Snauwaert, Evelien, Universiteit Gent, Ghent, Flanders, Belgium

Evelien Snauwaert, MD, PhD

• Van Wesemael, Pauline, Universiteit Gent, Ghent, Flanders, Belgium

Pauline Van Wesemael, MD

• Glorieux, Griet Lrl, Universiteit Gent, Ghent, Flanders, Belgium

Griet Lrl Glorieux, PhD

• Shroff, Rukshana, Great Ormond Street Hospital for Children NHS Foundation Trust, London, England, United Kingdom

Rukshana Shroff, MD, PhD

• Eloot, Sunny, Universiteit Gent, Ghent, Flanders, Belgium

Sunny Eloot, PhD

Background

In children undergoing chronic hemodialysis, there is insufficient evidence regarding the ideal dialysate to blood flow ratio (Q_D/Q_B) needed to achieve maximal solute clearance while simultaneously minimising water consumption. We aimed to determine the ideal Q_D/Q_B in different dialysis modalities by calculating dialyser extraction ratios (ER) for different uremic toxins. ER were also linked with dialysate consumption in order to find the most effective and eco-friendly dialysis setup.

Methods

At the start of a midweek dialysis session in five children, different dialysis modalities were sequentially applied for short intervals, i.e. hemodialysis (HD), predilution hemodiafiltration (preHDF), and postdilution haemodiafiltration (postHDF). With each modality, Q_D/Q_B was set to different values in the range 0.7-2.2. Substitution was kept constant in all settings at 0.33 times Q_B (postHDF) and 0.5 times Q_B (preHDF). Blood samples were collected from the dialyser inlet and outlet blood lines, centrifuged, and serum concentrations were determined for urea, beta-2-microglobulin, and myoglobin. ER was calculated from the relative change in concentration from dialyser inlet to outlet, and water consumption was estimated. ANOVA was used to check differences in ER for tertiles in either Q_D/Q_B or water consumption, and for different dialysis modalities.

Results

Two older children (age 14-15 years and body weight 31-44kg) were dialysed with Q_B 150mL/min, while three younger children (6-9 years and 21-25kg) were dialysed with Q_B 90-100mL/min. For each dialysis modality and each investigated toxin, ER was largest with postHDF, i.e. 0.91±0.05 (urea), 0.55±0.09 (β2M), and 0.31±0.09 (myoglobin) versus HD and preHDF (all P<0.01). For larger Q_D/Q_B, ER was only higher for urea (P=0.008), while no influence was observed for β2M and myoglobin. ER was also found higher for urea for larger water usage (P=0.005), while no influence was found for β2M and myoglobin.

Conclusion

We found overall higher ER in postHDF in comparison to HD and preHDF, and that higher dialysate flow rates (and thus higher water consumption) increase urea ER, while they do not enhance middle molecule clearance.