Simply put, the machine draws blood from an artery, passes it through a filter then returns it to a vein. While times may vary, the majority of those on dialysis dialyze for four hours a day, three days a week. Some dialysis units utilize high-flux machines that operate faster, but don't do as thorough a job. The blood circulates at a rate of 400 milliliters per minute -- so it actually gets cleaned hundreds of times per session. At any given time, only about two cups of blood are outside my veins.

There are two main types of dialysis -- hemodialysis and peritoneal dialysis.

Peritoneal dialysis is performed by the patient at home and uses the body's peritoneal membrane to filter out toxins. It must be done continuously, seven days a week. For more information on peritoneal dialysis, see links in the Resources chapter.

In hemodialysis, a machine is used to take the blood from an artery, filter it, then return it into a vein. It is usually done three times a week, and takes between two and four hours to do.

In order to get the blood from the body and return it, an access must be surgically implanted. The access joins an artery to a vein and is called a fistula or graft. If a patient needs dialysis immediately, and cannot wait for an arm access to heal, a temporary one can be placed in the neck or groin. This is called a permanent catheter or perm-cath. Since Dr. Pruchno wanted me start as soon as possible, this is what I had done.