The two main types of dialysis, hemodialysis and peritoneal dialysis. Hemodialysis removes wastes and water by circulating blood outside the body through an external filter, called a dialyzer, that contains a semipermeable membrane. Hemodialyis is usually conducted in an outpatient dialysis treatment center three times per week, with treatment times between 3 to 6 hours.
Hemodialysis may also be conducted at home. A small but growing number of clinics offer home HD in addition to standard HD treatments. The patient starts learning to do treatments at the clinic, working with a dialysis nurse. Most people who do home HD have helpers who train with them at the clinic. The helper can be a family member, neighbor, or close friend. Some programs do not require a helper if the patient can do all the tasks alone.
In peritoneal dialysis, wastes and water are removed from the blood inside the body using the peritoneal membrane as a natural semi-permeable membrane. Wastes and excess water move from the blood, across the peritoneal membrane, and into a special dialysis solution, called dialysate, in the abdominal cavity which has a composition similar to the fluid portion of blood.
The peritoneal membrane is a layer of tissue containing blood vessels that lines and surrounds the peritoneal, or abdominal, cavity. The dialysate is left there for a period of time to absorb waste products, and then it is drained out through the tube and discarded. This cycle or “exchange” is normally repeated 4-5 times during the day. Peritoneal dialysis is carried out at home by the patient.
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