Editing Kidney dialysis (section)

===Hemofiltration===
{{main|Hemofiltration}}
[[File:Continuous Venon Venous Haemofiltration with pre and post dilution (CVVH).svg|thumb|Continuous veno-venous haemofiltration with pre- and post-dilution (CVVH)]]
Hemofiltration is a similar treatment to hemodialysis, but it makes use of a different principle. The blood is pumped through a dialyzer or "hemofilter" as in dialysis, but no dialysate is used. A pressure gradient is applied; as a result, water moves across the very permeable membrane rapidly, "dragging" along with it many dissolved substances, including ones with large molecular weights, which are not cleared as well by hemodialysis. Salts and water lost from the blood during this process are replaced with a "substitution fluid" that is infused into the [[extracorporeal]] circuit during the treatment.