Renal Services

Frequently Asked Questions

What is hemodialysis?
Hemodialysis, also known as dialysis, is a treatment for people in the later stage of kidney failure. This treatment cleans the blood and removes wastes and excess water from the body. Blood is circulated through a machine, which contains a dialyzer (also called an artificial kidney). The dialyzer has two spaces separated by a thin membrane. Blood passes on one side of the membrane and dialysis fluid passes on the other. The wastes and excess water pass from the blood through the membrane into the dialysis fluid, which is then discarded. The cleansed blood is returned to the bloodstream.

What to expect during dialysis:
To be connected to the dialysis machine, the patient will need to have an access or entrance to the bloodstream. There are three ways a patient can be attached to a dialysis machine.

The most common method of providing permanent access to the bloodstream for dialysis is an internal fistula, a surgical connection between an artery and vein in the arm. When they are joined, the stronger bloodflow from the artery causes the vein to become larger. Needles can be inserted in the enlarged vein to connect the patient to the dialysis machine.

Another way to provide access to the bloodstream is to insert an internal graft. In this procedure, an artery is surgically connected to a vein with a short piece of special tubing placed under the skin. Needles can be inserted in this graft.

A third type of access is a catheter, which is made by inserting a soft tube into a blood vessel usually in the neck. This type of access is used when it is necessary to gain access to the bloodstream quickly, or when the veins in the arms are too small to provide enough blood for dialysis. This method usually is temporary until a permanent access site is ready.

Does dialysis hurt?
Insertion of the needles causes pain but only for a brief time. This can be difficult for some people. Occasionally nausea, muscle cramps or dizziness can occur because of the fast removal of extra water from the body, which may cause the blood pressure to drop.

How long does dialysis take?
Each dialysis treatment normally takes three to five hours, and usually three treatments a week are needed. Only a small amount of blood is out of the body at one time. Therefore your blood must circulate through the machine many times before it is cleansed.