n.
a technique of removing waste materials or poisons from the blood using the principle of dialysis. Haemodialysis is performed on patients whose kidneys have ceased to function; the process takes place in an artificial kidney, or dialyser. The stream of blood taken from an artery is circulated through the dialyser on one side of a semipermeable membrane, while a solution of similar electrolytic composition to the patient's blood circulates on the other side. Water and waste products from the patient's blood filter through the membrane, whose pores are too small to allow passage of blood cells and proteins. The purified blood is then returned to the patient's body through a vein.
Medical dictionary. 2011.