What is Dialysis?


Oct 27, 2022

What is Dialysis?

What is Dialysis?

Dialysis is a treatment for people with kidney disease whose kidneys are failing. Dialysis is like an artificial kidney, performing some of the important functions that damaged kidneys are no longer able to do.

What Do Kidneys Do?

One of your kidneys' important jobs is to clean your blood.  Kidneys filter the waste products, and extra fluid from your blood, and return nutrient rich blood into your bloodstream. The waste and extra fluid is passed from the body in your urine.  

Who Needs Dialysis? 

People who are experiencing kidney failure, or End Stage Renal Disease (ESRD) usually need dialysis treatments in order to stay alive. If you are a candidate for kidney transplant, dialysis can be used until there is a suitable kidney found for you.  

Medical conditions such as Diabetes, Lupus, and High Blood Pressure can damage the kidneys, especially if these conditions are not managed well. (For example, if you are not following dietary guidelines and not managing your blood glucose levels if diabetic). These conditions are the leading cause of developing Chronic Kidney Disease (CKD)

In CKD, the damage to your kidneys usually happens slowly, over time, progressing to End Stage Kidney Failure, and requiring dialysis or kidney transplant.  

A person can also experience acute kidney failure. This type of kidney failure happens suddenly and is often due to illness or injury.  In these circumstances, once the person has returned to health from the illness or injury, their kidney function returns to normal. These patients sometimes need just short term treatments of dialysis to help them while recovering.  

There are five stages in Chronic Kidney Disease.  Healthcare providers consider you to be in end stage kidney failure when you have lost 85 to 90 percent of your kidney function. At this point your kidneys have become too damaged to sustain life and dialysis and/or a kidney transplant are needed to continue life.

Is Kidney Failure Permanent?

Kidney failure is usually permanent, but not always. Some types of acute kidney failure do get better after treatments, However people suffering from chronic kidney disease that has progressed to end stage kidney failure, will not get better.  Their kidney failure is permanent. They will need Dialysis treatments the rest of their life, or perhaps up until they receive a kidney transplant.

What Does Dialysis Do?

Dialysis takes over some of the important work your kidneys can no longer do. Dialysis helps keep your body in balance by:  

  • Removing waste, salt, and extra fluids to prevent them from building up in your body and making you very ill. 
  • Keeping a safe level of chemicals in the blood. 
  • Helps to control blood pressure.

Are There Different Types Of Dialysis? 

There are two main types of Dialysis, Hemodialysis and Peritoneal Dialysis. 


Hemodialysis is done with a machine called a dialyzer Blood removed from your body is filtered through the dialyzer machine where waste products and extra fluids are removed and then returns the cleaned blood back into your body.  The process takes approximately three to five hours and normally is done three times per week.  

Hemodialysis is usually done in a dialysis center, clinic or hospital, though you may also choose to have hemodialysis done in your own home.  You must have a place to store equipment and supplies needed, and someone to help you, such as a family member, a friend, or if you choose you may have a home healthcare professional.  Having your hemodialysis treatments in the home has some benefits including shorter treatment times done four to seven times per week, and the option of having the treatment done at night while you are sleeping.  

Before you begin hemodialysis treatments, you will need to have a minor surgical procedure that will make it easier to access your bloodstream.  A surgeon will do an Arteriovenous Fistula, (AV Fistula)This is when an artery and a vein are connected in your arm. If your artery and vein are too short to connect, the surgeon can do an Arteriovenous Graft.  In this case the surgeon will use a graft, (a soft, hollow tube) to connect your artery and vein.  AV Fistulas and grafts enlarge the connected artery and vein which makes access for your dialysis treatments easier, and allows blood to flow in and out of your body faster.  

In situations where dialysis must be started immediately, a thin tube called a catheter can be inserted into a vein in your neck, chest, or leg for a more temporary type of access.  

During your hemodialysis treatments a needle is inserted into your arm where you have had the access point enlarged by a surgeon.  Your blood is removed and circulated through the dialyzer machine, which filters, then returns the cleaned blood back into your bloodstream.  

The time needed for your dialysis depends upon a number of things:

  • Your size
  • Type of “artificial kidney” you are using
  • How well your kidneys work
  • How much fluid weight you gain in between treatments
  • How much waste in your body

Understanding Hemodialysis Video

This video developed by Fresenius Medical Care explains the hemodialysis process.

Peritoneal Dialysis

Peritoneal Dialysis does not use a machine to filter, or clean your blood. Instead, your blood is cleaned inside your own body.  You will have surgery to implant a Peritoneal Dialysis (PD) Catheter. Into your abdomen.  The catheter helps to filter the blood through a membrane in your abdomen called the peritoneum.  During this type of dialysis treatment, a special fluid called dialysate flows into the peritoneum.  The dialysate absorbs the waste products.  Once the dialysate draws waste out of the bloodstream, it is then drained from your abdomen.  The process takes a few hours and needs to be repeated four to six times each day.  The exchange of fluids can be done as you are sleeping or awake. 

There are different types of peritoneal dialysis; Continuous Ambulatory Peritoneal Dialysis (CAPD) where the abdomen is filled and drained multiple times each day.  It does not require a machine, and is done while you are awake.  Continuous Cycling Peritoneal Dialysis (CCPD) uses a machine to cycle the fluid in and out of the abdomen and is usually done at night while you are asleep.  Intermittent Peritoneal Dialysis (IPD) is usually done in the hospital, and uses the same machine as CCPD, but the process is longer.  

Both hemodialysis and peritoneal dialysis can be done in your own home.

Understanding Peritoneal Dialysis Video

This video developed by Fresenius Medical Care explains the hemodialysis process.

How Long Can I Live Without Dialysis With End Stage Renal Disease (ESRD)?

Managing kidney failure without dialysis is called medical management.  How long a person survives depends on your overall health, and any other medical conditions you may have.  People who decide to not be treated with dialysis or to stop their dialysis treatments can live for a few weeks to a few months. Dialysis can not reverse the damage done to your kidneys, this is something you must continue for your lifetime unless you are a candidate for transplant and are waiting for an available kidney for transplant.  

Each option you have if you are facing end stage renal failure, is serious and life altering.  You will have a healthcare team of professional providers to help and educate you in this journey, remember though, you are the captain of your team,  the people around you have the skills and knowledge to make whatever treatment you decide on, a positive journey, but the decisions are yours and what feels best for you.


National Kidney Foundation

Cleveland Clinic

Fresenius Medical Care

About the Author

Monica Thomas

Monica McCarthy has bachelors in Political Science and Criminal Justice from Central Washington University.  A majority of her career was spent as a political consultant.   She currently works at KidneyLuv as a staff writer.

Patient Education Disclaimer

This material is for informational purposes only. It does not replace the advice or counsel of a doctor or health care professional. KidneyLuv makes every effort to provide information that is accurate and timely, but makes no guarantee in this regard. You should consult with, and rely only on the advice of, your physician or health care professional.

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