Hemodialysis and the Kidneys

During hemodialysis, you will be hooked up to a machine that takes over the kidneys’ job of filtering blood. Before the first session, the doctor will need to create an entrance into one of your blood vessels so your body can be connected to the filtering machine during each visit. This is called a vascular access. It is a place on your body where blood can be removed and then returned. This can be done by:

  • Connecting an artery to a vein to create a larger blood vessel area, called a fistula
  • Joining (grafting) an artery and vein together using a soft plastic tube
  • Inserting a thin plastic tube into a large vein in the neck or groin area of the leg; this type of access is temporary.

You may need temporary or permanent access. The type of access and how long you need it depends on your individual condition. Experts recommend creating an access weeks or months before your first dialysis session so it has a chance to heal properly before using it.

During a hemodialysis session, your blood flows a little bit at a time through a special filter inside the machine. The filter removes wastes and extra fluids from your blood, but retains the proper balance of minerals such as potassium and sodium. Once the blood is cleaned, it is returned to the body.