Your kidneys help filter waste, excess fluid, and toxins from your blood. They are also important for blood cell production and bone health. If kidneys don't work properly, harmful substances build up in the body, blood pressure can rise, and too much fluid can collect in the body's tissues, which leads to swelling, called edema.
Creatinine is a waste product from the normal breakdown of muscle tissue. As creatinine is produced, it's filtered through the kidneys and excreted in urine. Doctors measure the blood creatinine level as a test of kidney function. The kidneys' ability to handle creatinine is called the creatinine clearance rate, which helps to estimate the glomerular filtration rate (GFR) -- the rate of blood flow through the kidneys.
Kidney dialysis is a life-support treatment that uses a special machine to filter harmful wastes, salt, and excess fluid from your blood. This restores the blood to a normal, healthy balance. Dialysis replaces many of the kidney's important functions.
There are different types of kidney dialysis, including:
Hemodialysis. Blood is filtered using a dialyzer and dialysis machine.
Peritoneal dialysis. Blood is filtered inside the body after the abdomen is filled with a special cleaning solution.
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.
Patients often need dialysis treatments several times a week. How long each hemodialysis session lasts depends on:
How well your kidneys work
How much fluid you gained since your last dialysis session
How much waste has gathered in your blood since your last dialysis session