What Is Hemodialysis?

Hemodialysis is a medical treatment that uses a machine with a special filter to take waste and extra water out of the blood. It can take over this job when the kidneys can't do it.

Why Do People Need Hemodialysis?

The main job of the kidneys is to clean the blood. They take out extra water and waste (things the body doesn't need). These leave the body as pee (urine).

If the kidneys don't work as they should, waste quickly builds up in the body and makes a person sick. When the kidneys stop removing enough waste and extra water from the blood, the person has kidney failure. Then, the person needs dialysis to clean the blood because the kidneys can't.

There are two types of dialysis: hemodialysis (hee-moh-dye-AL-ih-sis) and peritoneal dialysis (pair-eh-tih-NEEL dye-AL-ih-sis).

How Does Hemodialysis Work?

During hemodialysis, a machine removes blood from the bloodstream, cleans it, and returns it to the bloodstream. Only a safe amount of blood leaves the body at one time.

Before they get hemodialysis, children need a soft, flexible tube (a catheter) placed into a large vein, usually in the chest. This tube is a temporary pathway to get blood out of the bloodstream and back in again.

The catheter stays in place until doctors do another procedure to make a more permanent pathway. This permanent pathway is stronger than normal blood vessels and can handle the faster blood flow and repeated needle sticks needed for hemodialysis.

Doctors have two options for the pathway, which both happen in an arm. They can make:

  • a fistula (FISS-chuh-luh) by joining an artery to a nearby vein under the skin to make a bigger blood vessel
    or
  • a graft by using a flexible tube to join the artery to the vein

What Happens During Hemodialysis?

Hemodialysis usually takes place in a special clinic called a dialysis center. Some kids get treatments at a hospital.

A nurse connects the catheter, fistula, or graft to a needle and tubing that takes blood from the bloodstream. The blood goes into a special filter called a dialyzer (DYE-uh-lye-zer) or "artificial kidney."

The dialyzer has two parts: one for blood and one for a cleaning fluid called dialysate (dye-AL-uh-zate). A thin wall called a membrane separates these two parts. The membrane keeps important things inside the blood, like blood cells and proteins, which are too large to pass through it. Small waste and extra water pass through the membrane and are washed away. When the blood is clean, the machine sends it back to the child through another tube.

How Long Does Hemodialysis Take?

Most kids get dialysis three times a week. It takes about 4 hours each time.

During treatment, kids can lie down or sit in a chair. They can read, watch TV, play video games, or nap.

Is Hemodialysis Uncomfortable?

Each time a child has a hemodialysis treatment, a needle goes into the fistula or graft. After repeated treatments, most kids get used to the feeling. After treatment, kids sometimes feel tired. Some may have muscle cramps, headaches, nausea, or dizziness, but this is rare.

Are There Any Risks to Hemodialysis?

Hemodialysis does have some risks, including:

  • Problems with the catheter, fistula, or graft. Germs can get into the catheter, fistula, or graft and cause an infection. Blood clots can block the catheter, fistula, or graft. The treatment team will teach you how to recognize these problems so they can be handled right away.
  • Low blood pressure. Rarely, a person's blood pressure can go down during treatment. If this happens, they might be dizzy, have a headache, or feel sick (or throw up). The medical team can change the treatment plan to avoid this.
  • Itching. Hemodialysis can make the skin feel itchy, especially during or right after a treatment.
  • Sleep problems. Some people can have trouble sleeping due to aching or restless legs or brief pauses in breathing.

How Can Parents Help?

When kids need dialysis, staying healthy helps them avoid problems and feel their best. Here are a few tips:

  • Help kids eat the right foods. Kids on dialysis need to get the right amount — not too much or too little — of fluids, salt, vitamins, and minerals each day. Too much potassium or phosphorus, for example, can affect the heartbeat or weaken bones. A doctor or a dietitian at the dialysis clinic can give advice on the right meal plan.
  • Help kids remember to take medicine if needed. Kids often need medicines to control their blood pressure, help produce red blood cells, and control nutrient levels in the blood. Follow the doctor's instructions, and ask before your child takes any nonprescription medicines, vitamins, or other supplements.
  • Plan ahead. Make sure your child can continue treatments during travel. If you go to a dialysis clinic in a different town, call ahead and make sure they can fit your child into their schedule.

What Else Should I Know?

Kids and teens who get hemodialysis can go to school or work. They can still do most of their usual activities, planned around the dialysis schedule. Jobs and sports with lots of heavy lifting or contact, though, may not be OK to do. But even with some limits, kids still can do many things they enjoy.

Some people need dialysis treatments for the rest of their lives. If so, they might switch back and forth between hemodialysis and peritoneal dialysis, which usually can be done at home.

Back to Articles

Related Articles

Dialysis

Dialysis is a medical treatment that can take over the job of cleaning the blood when the kidneys can't.

Read More

Peritoneal Dialysis

This medical treatment helps people with kidney failure. It can be done at home, often overnight, to take over the kidneys' job of filtering blood.

Read More

Kidney Diseases in Childhood

The kidneys play a critical role in health. When something goes wrong, it could indicate a kidney disease. What are kidney diseases, and how can they be treated?

Read More

When Your Child Has a Chronic Kidney Disease

Parents of kids who have a chronic kidney disease often worry about what might happen next, how their child feels, and what treatments are likely to be involved. Find answers here.

Read More

When Your Child Needs a Kidney Transplant

If your child needs a kidney transplant, you're probably feeling lots of emotions. Fortunately, many kids who undergo kidney transplants go on to live normal, healthy lives.

Read More

Kidney Disease

Sometimes, the kidneys can't do their job properly. In teens, kidney disease is usually due to infections, structural issues, glomerulonephritis, or nephrotic syndrome.

Read More

Kidney Transplant

If the kidneys stop working, a person will need either dialysis or a transplant. Get the facts on kidney transplant in this article for teens.

Read More

Kidneys and Urinary Tract

The bean-shaped kidneys, each about the size of a child's fist, are essential to our health. Their most important role is to filter blood and produce urine.

Read More

Kidneys and Urinary Tract

The kidneys perform several functions that are essential to health, the most important of which are to filter blood and produce urine.

Read More

Ultrasound: Renal (Kidneys, Ureters, Bladder)

A renal ultrasound makes images of your child's kidneys, ureters, and bladder. Doctors may order this test if they suspect kidney damage, cysts, tumors, kidney stones, or complications from urinary tract infections.

Read More

Your Kidneys

You need at least one kidney to live. Find out why in this article for kids.

Read More

Dialysis

Dialysis is a medical treatment that can take over the job of filtering the blood until a person's failing kidneys heal or are replaced with a kidney transplant. Find out more in this article for teens.

Read More

Hemodialysis

Hemodialysis is the type of kidney dialysis that doctors use most to take over the kidneys' job of filtering the blood. Find out more in this article for teens.

Read More

Peritoneal Dialysis

This medical treatment helps people with kidney failure. It can be done at home, often overnight, to take over the kidneys' job of filtering blood. Find out more in this article for teens.

Read More

Glomerulonephritis

Glomerulonephritis happens when tiny filtering units in the kidneys stop working properly. Most cases get better on their own or with treatment.

Read More

Glomerulonephritis

With glomerulonephritis, tiny filtering units in the kidneys stop working properly, causing problems like too much fluid in the body and swelling. Most of the time it can be treated. Find out more.

Read More

Hepatitis C

The hepatitis C virus (HCV) spreads through blood or other body fluids, and can lead to cirrhosis or liver cancer. The most common way people become infected is by sharing drug paraphernalia.

Read More

Hepatitis C

The hepatitis C virus (HCV) spreads through blood or other body fluids, and can lead to cirrhosis or liver cancer. The most common way people become infected is by sharing drug paraphernalia.

Read More

Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.