• In peritoneal dialysis, the semi permeable membrane is the peritoneal membrane
• Water is removed by an osmotic gradient between the dialysis fluid and the plasma
• Other substances are removed by dialysis and also by bulk movement with the water
• The major complication is infection with skin or gut derived organisms
• In hemofiltration blood is forced through a semi permeable membrane and water and small molecules are filtered out of the blood
• Hemofiltration is slower and less physiologically disturbing than hemodialysis and is used in intensive care units on very sick patients
• Plasma exchange works in the same way, but the pores in the membrane are larger and larger molecules including antibodies and clotting factors are removed
• Plasma exchange is used to remove unwanted proteins such as anti-glomerular basement membrane antibodies
• Hemoperfusion involves passing blood over a substance such as charcoal which can bind toxins or drugs. The blood is then returned to the body.

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C. A. O'Callaghan 2004