High-volume Hemofiltration

The science behind achieving high-volume hemofiltration, along with further reading.

Achieving High-volume Hemofiltration

As blood passes through the haemofilter. plasma water is removed by hydrostatic pressure, and the ratio of plasma water that is removed to blood flow is termed the filtration fraction.

As the filtration fraction increases, this leads to an increase in haematocrit and plasma proteins as blood flows through the dialyser, which increases the risk of clotting.

To reduce these changes, EuDial recommended a filtration fraction of 20-25%. Although in clinical practice the filtration fraction (FF) is expressed as the ultrafiltration flow to blood flow, in reality the filtration fraction should also take into account haematocrit and plasma total proteins.

To increase the amount of convective clearance, but maintain the filtration fraction, several parameters need to be considered:

1. Haemofilter choice

  • a) designed for convection with
  • b) high hydraulic permeability

2. Increase blood flow

  • a) may need to increase fistula needle size

3. Increase the session time

4. Avoid high haematocrit.

Filtration fraction ratio of convective to blood flow
Filtration fraction ratio of convective to blood flow

Haemoglobin and plasma proteins affect filtration fraction
Haemoglobin and plasma proteins affect filtration fraction

Further reading

  1. Tattersall JE, Ward RA; EUDIAL group. Online haemodiafiltration: definition, dose quantification and safety revisited. Nephrol Dial Transplant. 2013 Mar;28(3): 542-50.
  2. de Roij van Zuijdewijn CLM, Chapdelaine I, Nubé MJ, et al. Achieving high convection volumes in postdilution online hemodiafiltration: a prospective multicenter study. Clin Kidney J. 2017 Dec;10(6): 804-812.
  3. Chapdelaine I, de Roij van Zuijdewijn CL, Mostovaya IM, et al. Optimization of the convection volume in online post-dilution haemodiafiltration: practical and technical issues. Clin Kidney J. 2015 Apr;8(2): 191-8.
  4. Mostovaya IM, Grooteman MP, Basile C, Davenport A, et al. High convection volume in online post-dilution haemodiafiltration: relevance, safety and costs. Clin Kidney J. 2015 Aug;8(4): 368-73.
  5. Marcelli D, Scholz C, Ponce P, Sousa T, et al. High-volume postdilution hemodiafiltration is a feasible option in routine clinical practice. Artif Organs. 2015 Feb;39(2): 142-9.
  6. Canaud B, Barbieri C, Marcelli D, et al. Optimal convection volume for improving patient outcomes in an international incident dialysis cohort treated with online hemodiafiltration. Kidney Int. 2015 Nov;88(5): 1108-16.

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