If your kidneys cannot keep your blood filtered and purified, dialysis performs the function of your kidneys using a machine.

The kidneys filter your blood by removing waste and excess fluid from your body. This waste is sent to the bladder to be eliminated when you urinate.

When your kidneys can’t perform well due to disease or injury, dialysis can help keep the body running. Kidney failure occurs when the kidneys perform only 10% to 15% of their typical function. Without dialysis, salts and other waste products accumulate in the blood and can damage other organs.

Learn more about dialysis, including the different types and possible risks.

Types of dialysis can include hemodialysis, peritoneal dialysis, and continuous renal replacement therapy (CRRT).

What is hemodialysis?

Hemodialysis is a form of dialysis that uses a filter called a hemodialyzer to remove waste and extra fluid from the blood.

Before hemodialysis

A doctor performs minor surgery to create an entry point into your blood vessels. This is done in advance, as it may take several months to heal.

The three types of entrance points include:

  • Arteriovenous (AV) fistula
  • AV graft
  • Vascular access catheter

Both the AV fistula and AV graft are designed for long-term dialysis treatments. Catheters are designed for short-term or temporary use.

During hemodialysis

During treatment, your blood is removed from the body and filtered through the hemodialyzer. The filtered blood is then returned to the body with the help of a dialysis machine.

Hemodialysis treatments last about 4 hours each, up to 3 times per week. You may also have hemodialysis treatment in shorter, more frequent sessions.

At first, most hemodialysis treatments are performed at a hospital, doctor’s office, or dialysis center. The length of treatment depends on your body size, the amount of waste in your body, and your current health.

After hemodialysis

After you’ve been on hemodialysis for an extended period, you may be ready to give yourself dialysis treatments at home. This option is common for people who need long-term treatment.

What is peritoneal dialysis?

Peritoneal dialysis uses a peritoneal dialysis (PD) catheter in your abdomen to filter your blood. The catheter filters blood through the peritoneum, a membrane in your abdomen.

Before peritoneal dialysis

A doctor performs surgery to implant the catheter. This typically happens about 3 weeks in advance.

You typically receive training from a dialysis nurse for a couple of weeks before dialysis to learn to care for the catheter site and perform the exchanges.

During peritoneal dialysis

During treatment, a special fluid called dialysate flows into the peritoneum. The dialysate absorbs waste. Once the dialysate draws waste out of the bloodstream, it’s drained from your abdomen.

This process can take a few hours and needs to be repeated 3 to 5 times daily. But this fluid exchange can happen while you’re sleeping or awake—and even during daily activities.

Types of peritoneal dialysis include:

  • Continuous ambulatory peritoneal dialysis (CAPD): Your abdomen is filled and drained multiple times daily. This method doesn’t require a machine and must be performed while awake.
  • Continuous cycling peritoneal dialysis (CCPD): CCPD uses a machine to cycle the fluid in and out of your abdomen. It’s usually done at night while you sleep.
  • Intermittent peritoneal dialysis (IPD): This treatment is usually performed in the hospital, though you may perform it at home. It uses the same machine as CCPD, but the process takes longer.

After peritoneal dialysis

After treatment, you’ll need to take care of your exit site, catheter, and other supplies to prevent infection.

What is CRRT (continuous renal replacement therapy)?

CRRT is used primarily in the intensive care unit for people with acute kidney failure. It’s also known as hemofiltration.

A machine passes the blood through the tubing. A filter then removes waste products and water. A machine returns the blood to the body, along with replacement fluid. This procedure is performed 24 hours or more at a time.

All three forms of dialysis can carry certain risks.

Risks associated with hemodialysis

Hemodialysis risks include:

Risks associated with peritoneal dialysis

Peritoneal dialysis may increase your risk of infections in or around the catheter site, such as peritonitis.

Other risks include:

Risks associated with CRRT

The risks associated with CRRT include:

Those who undergo long-term dialysis are also at risk of developing other medical conditions, including amyloidosis.

Some people develop depression or anxiety after receiving a diagnosis of long-term kidney failure. If you’re having thoughts associated with depression, talk with a member of your care team or a mental health professional. The National Alliance on Mental Illness also has resources for dealing with depression and chronic conditions.

Other treatment options may help manage your symptoms if you decide not to pursue dialysis.

One option is anemia management. When the kidneys work correctly, the hormone erythropoietin (EPO) is produced naturally. To help with an under-functioning kidney, you can get an injection of EPO every week.

Maintaining healthy blood pressure can help slow the deterioration of your kidney. Drink fluids to avoid dehydration. Talk with a doctor before using any anti-inflammatory drugs, including ibuprofen (Advil) and diclofenac (Solaraze, Voltaren).

A kidney transplant may be an option. Talk with a doctor to see if a transplant is right for you. You may not be a good candidate for a kidney transplant if you:

  • smoke
  • heavily use alcohol
  • have obesity
  • have an untreated mental health condition

A medical professional may provide specific directions. You may need to fast for a certain amount of time before treatment.

You may want to wear comfortable clothing during treatment.

You can perform both hemodialysis and peritoneal dialysis at home. Peritoneal dialysis can be performed alone, while hemodialysis often requires a partner. This can be a friend, family member, or dialysis nurse.

With either type, you’ll receive thorough training from a medical professional beforehand.

Dialysis can temporarily serve the same function as kidneys until your kidneys repair themselves and begin to work on their own again.

But if you have chronic kidney disease, you typically go on dialysis permanently or until a kidney transplant becomes an option.

While on hemodialysis, you’ll need to limit your potassium, phosphorus, and sodium intake. You may need to keep a record of how much liquid you consume. Having too much fluid in the body can cause problems.

A nephrologist (kidney doctor) typically has a dietician on the team to help guide dietary choices.

Being consistent with your dialysis will also decrease your chances of needing a kidney transplant.

Stopping dialysis

If you’re considering stopping dialysis, mention any concerns to a doctor.

While it’s in your right to stop any treatment at any time, they may suggest you talk with a mental health professional before ending this life-saving treatment. If the condition causing kidney failure hasn’t been corrected, stopping dialysis will eventually lead to death.

Dialysis is a life-saving therapy that can replace the work of non-functioning kidneys. This may be due to acute kidney failure, chronic kidney disease, or other kidney issues. It works by filtering your blood to help restore both fluid and electrolyte balances.

There are also risks and complications to consider, as well as problems with treatment access. Talk with a doctor about the pros and cons of dialysis, and ask them which type may be best for your situation.