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Surgeries and Procedures: Blood Transfusion

Reviewed by: Kate M. Cronan, MD
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What Is a Blood Transfusion?

A blood transfusion is when a donor's blood is transferred to a patient. The blood is transferred into the patient's body through a vein. A blood transfusion can make up for the loss of blood.

What Is Blood Made of?

Blood is a mixture of cells and liquid, and each part has a specific job:

  • Red blood cells carry oxygen to the body's tissues and remove carbon dioxide. These cells are the ones that are most commonly transfused.
  • White blood cells help the body fight infection by making antibodies, (proteins that help destroy germs in the body).
  • Platelets, the smallest blood cells, help to clot the blood and control bleeding.
  • Plasma, the pale yellow liquid part of whole blood, is a mixture of water, proteins, electrolytes, carbohydrates, cholesterol, hormones, and vitamins.

Why Does a Person Need a Transfusion?

The main reasons why a child may need a blood transfusion are:

  • Loss of blood during surgery or from an injury or an illness.
  • Too little blood is being made. Some illnesses and treatments can prevent the bone marrow from making blood (for example, chemotherapy decreases production of new blood cells).
  • To prevent complications from a blood or bleeding disorder, such as sickle cell disease, thalassemia, or anemia caused by kidney disease, hemophilia, or von Willebrand disease.

Where Does the Blood for a Transfusion Comes From?

Because there's no substitute for blood, the blood supply used for transfusion must be donated. The three types of blood donation are:

Autologous (ah-TOL-uh-gus) blood donation. This is when someone donates their own blood ahead of time for a planned surgery or other procedure. There is no age requirement, but in general, kids don't donate their blood for their own use until they're over age 12.

Directed donation. This is when a family member or friend with a compatible (good fit) blood type donates blood specifically for use by a patient in need of transfusion.

Volunteer donation. There's no medical proof that blood from directed donors is any safer than blood from volunteer donors. So most patients receive blood donated through blood drives. These are often run by agencies like the American Red Cross. The minimum age for donating blood is 16 or 17 years old, depending on where a person lives.

How Should We Prepare for a Blood Transfusion?

If your child needs a blood transfusion, the doctor will describe the procedure. Parents should ask questions if the explanation isn't clear. A parent or legal guardian will need to sign an informed consent form. This states that you understand the procedure and its risks, and give your permission for your child to have it.

If the situation is not a life-threatening emergency, two important tests will be done before the transfusion:

1. Blood typing. To confirm your child's blood type, a nurse or technician will draw a sample from a vein in your child's arm. (Except for the brief needle stick, this isn't painful and only takes a few minutes.) This blood is immediately labeled with your child's name, birth date, and medical record number, and an armband with matching information is made for your child to wear. The blood is then sent to the hospital's blood bank lab, where technicians test it for blood type.

The 4 types of blood are:

  • type A
  • type B
  • type O
  • type AB

Each blood type also can be positive (+) or negative.

2. Cross-matching. After blood typing is complete, a compatible donor blood is chosen. As a final check, a blood bank technologist will mix a small sample of your child's blood with a small sample of the donor blood to confirm they are compatible. Then the blood is labeled with your child's name, birth date, and medical record number and taken to where your child will get the transfusion.

What Happens During a Blood Transfusion?

When a child gets a transfusion:

  • Blood is given through a needle placed in a vein.
  • The needle is attached to thin plastic tubing that connects to a plastic bag containing the blood.
  • The vital signs (temperature, blood pressure, and heart rate) are checked before, during, and after the transfusion.
  • A nurse watches for any signs of an allergic or other type of reaction, including rash, fever, headache, or swelling.

Transfusions usually take 1 to 4 hours, depending on how much blood is given and your child's blood type. You can stay with your child, who will be awake. Your child can sit comfortably in a reclining chair or lie down on a bed, watch a movie, listen to music, or play quietly, and might be able to eat and drink, walk around a bit, and use the bathroom.

After the transfusion, if your child is going home, the plastic tube is removed from the vein and a bandage is placed over the area. The site may be slightly sore or tingly for a little while. Medicine may be given for any mild side effects, such as fever or headache.

Are There Any Risks to Blood Transfusions?

Some people worry about getting diseases from infected blood. But the United States has one of the safest blood supplies in the world. Many organizations, including community blood banks and the federal government, work hard to make sure that the blood supply is safe.

The risk of getting a disease like HIV or hepatitis through a transfusion is extremely low in the United States because of very thorough blood screening. Also, the needles and other equipment used are sterile, and are used only on one person and then thrown away in special containers.

If you have any questions about the risks of the transfusion, ask your child's health care team.

What Are the Benefits of Blood Transfusions?

In kids with anemia or those getting chemotherapy, the greatest benefit of a transfusion is increased blood flow to nourish the organs and improve oxygen levels in the body. This can keep them from feeling too tired and help give them enough energy for the activities of daily life. Benefits like this often are felt fairly quickly.

For patients with bleeding problems, transfusions with platelets or plasma can help to control or prevent bleeding complications.

When your child is having any kind of procedure, it's understandable to be a little uneasy. But it helps to know that blood transfusions are common procedures and complications are rare. Talk with your child's doctor or health care team if you still have concerns.

Reviewed by: Kate M. Cronan, MD
Date reviewed: January 2019