A quick reference guide to haemofiltration and renal failure March ...

MANIPULATION OF THESE H PRINCIPLES
Diffusion is increased by;
• Increasing the rate of the dialysate flow
• Increasing the rate of blood flow
• Using countercurrent flow
• Composition of dialysate fluid to increase the concentration
gradient
• Increasing the surface area of the membrane
Diffusion is decreased by;
• Decreasing the rate of the dialysis flow
• Decreasing the rate of blood flow
• Dilution of the blood before the filter (pre-dilution
replacement fluid)
• Decreasing the area of the membrane
Ultrafiltration and Convection are increased by;
• An increase in positive pressure on the blood side of the
circuit. This can be caused by either an increase in blood
flow or an increase in the flow of pre-dilution replacement
fluid.
• An increase in negative pressure on the ultrafiltrate side of
the membrane.
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