comparison of two dialyzers
Research type
Research Study
Full title
Pilot study to determine the effect of different dialyzer membranes on clotting during haemodiafiltration treatments in patients with chronic kidney disease
IRAS ID
147383
Contact name
Andrew Davenport
Contact email
Sponsor organisation
University College London
Duration of Study in the UK
0 years, 11 months, 22 days
Research summary
The Royal Free Hospital has more than 750 kidney dialysis patients. A dialyzer is used to remove waste products that build up between dialysis sessions. Our dialyzer contract exceeds £1,000,000. We need to compare different dialyzers to determine whether one is better than another, so that we can then make an informed decision about which dialyzer to buy for the next 3 year contract.
Haemodiafiltration is used at the Royal Free Hospital. Whereas traditional haemodialysis removes molecule by diffusion, haemodiafiltration removes molecules by convection. During convection there is a bulk movement of water across the dialyzer capillary wall, and any solute in the water passes out from the blood with this convective water movement, provided the molecule is small enough to pass through the holes (pores) in the capillary dialyzer membrane. Whereas diffusion is very effective at removing small water soluble molecules, diffusion is much slower for larger molecules, and as such these are not well cleared by diffusion and so accumulate over time in haemodialysis patients. On the other hand convection is much more effective at removing larger molecular weight molecules, as so prevents accumulation of these larger molecules in patients treated by haemodiafiltration.As such a different dialyzer design is required for haemodiafiltration compared to haemodialysis.
Convective leads to concentration of the remaining blood, red blood cells (haemoglobin), and other elements of the blood, including platelets and leukocytes. Platelets are important in clotting, and activated platelets can initiate clotting by releasing microparticles. Clotting of the small fibres in the haemodiafilter, reduces the amount of convection which can be achieved. As such clotting in the haemodiafilter is more likely to occur with haemodiafiltration, and clotting then reduces the effectiveness of the treatment.
We wish to compare 2 dialyzers designed for haemodiafiltration in terms of convective clearance and clot formation.
REC name
London - Westminster Research Ethics Committee
REC reference
15/LO/0102
Date of REC Opinion
27 Feb 2015
REC opinion
Further Information Favourable Opinion