What is dialysis?
To understand dialysis, you need to know about the kidneys and what
they do. The kidneys are organs located in the back of your body,
just below your ribs. They look like beans and are about the size
of a fist. Most people are born with two kidneys, one on each side,
but people can live normally with one.
The kidneys do many good things for the body. The main job of
the kidneys is to filter the body's blood supply to remove extra
water, salt and the waste products left over after the body uses
the energy it needs to live. The extra fluid and waste leave the
body when you urinate (pee).
Since the body is made up mostly of water, the kidneys make sure
there is the right balance of fluid for the body to stay healthy.
The kidneys also control blood pressure, maintain the levels of
certain chemicals in the blood and make substances necessary for
the body to function correctly.
Each kidney contains about one million tiny structures, called
nephrons, along with a series of collecting tubes. This is where
the filtering takes place. Sometimes the nephrons start to lose
their ability to filter blood. This is most often caused by
conditions such as diabetes, high blood pressure, and obesity.
These conditions make the kidneys work extra hard, and they start
to break down. Most often, damage to the kidneys happens slowly
over a period of time.
When the kidneys do not work, the blood must be filtered another
way. This is done using a treatment called dialysis. Dialysis does
what the kidneys are no longer able to do. There are different
types of dialysis. They differ in the way the filtering is done.
The main methods of dialysis are hemodialysis and peritoneal
dialysis. You and your doctor will discuss which type of dialysis
is best for you.
What is hemodialysis?
During hemodialysis, a machine with a special filter (called a
dialyzer) is used to clean the blood. The filter is sometimes
called an "artificial kidney." The blood flows from the body into
the dialyzer where the filtering takes place, and then the clean
blood returns to the body. The blood leaves and returns through a
small opening called an access. The access is made by your doctor
during a minor procedure and stays in place between treatments.
During treatment, needles are placed into the access to allow the
blood to flow in and out.