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.