Blood Transfusions

What you should know about blood transfusions.

There are many reasons why you or a loved one might need a blood transfusion. If your physician has decided you might need blood or blood products, he or she will explain the reason why.

These reasons frequently include:

  • A sudden loss of blood (sometimes as high as a quarter of the normal blood volume)
  • An anticipated loss of blood during surgery
  • A low hemoglobin before, during or after surgery
  • Severe heart or lung disease
  • Bone marrow failure
  • Moderate to severe anemia

What is blood made of? Human blood is made of fluid called plasma that carries red and white blood cells and platelets. Each part of blood has special functions and can be separated from each other. The bone marrow is the soft, spongy material in the center of the bones that produces about 95 percent of the body's blood cells.

What are red blood cells? Red blood cells carry oxygen from the lungs to other body organs and carry carbon dioxide back to the lungs. A certain number of these cells are needed for the body to function. Bleeding due to trauma, surgery or disease may cause a low red blood cell count. Red blood cells are the most common type of transfusion.

What are white blood cells? White blood cells fight infections by destroying bacteria, viruses and other germs. White blood cells are rarely transfused. They are usually reserved as a temporary measure for people who have a low white cell count and severe infection that is not responsive to antibiotic therapy.

What are platelets? Platelets help control bleeding by making clots in blood vessels opened by injury or surgery. The body may not be able to make enough platelets because of bone marrow disorders, increased destruction of platelets or medications such as chemotherapy. Platelets can be transfused before a procedure that may cause a person with a low platelet count to bleed.

What is plasma? Plasma carries the blood cells throughout the body and contains proteins, vitamins and minerals. Some of the proteins help the blood to clot. Plasma or fresh frozen plasma can be transfused in people who have a severe deficiency of certain clotting components of the blood.

Are blood transfusions safe? The blood used at most hospitals is from volunteer donors. Donors are not paid for giving blood or blood products. Each blood donor must answer medical history questions and be given a limited physical examination before being accepted as a donor. The donated blood is carefully tested for hepatitis viruses B and C, human immunodeficiency virus (HIV), human T-lymphotropic viruses (HTLV) I and II, syphilis and West Nile virus. These tests decrease the chances of transfusion-related infections.

How is blood transfused? Blood is collected and stored in sterile bags. The bags are used once and then thrown away. Before blood is given to you, it is cross-matched with your own blood to make sure it is compatible. The blood will be given through a needle or catheter placed in the vein. Your temperature, blood pressure and heart rate will be checked many times while the blood is being given. It may take a few hours to complete the process.

What is directed donation? A directed (or designated) blood donation is one in which a person donates blood that is reserved (at the time of donation) for the transfusion of a specific patient at a later date. The donor is usually a family member or a close friend that has been chosen by the patient or the patient's family. Consult your physician if you are interested in learning more about directed donation. An autologous donation is another type of directed donation. An autologous donation is blood collected from the patient in advance of a planned surgery for that patient’s own use.

Are directed donors safer than volunteer donors? There is no proof that directed donors are safer than volunteer donors. Not all directed donor blood will be compatible with the patient's blood.

Are there risks in receiving a blood transfusion? Most transfusions are performed without any problems. Mild side effects may include symptoms of an allergic reaction such as headache, fever, itching, increased breathing effort or rash. This type of reaction can usually be treated with medication, should you require additional transfusions. Serious side effects are rare and may include difficulty breathing and a sudden drop in blood pressure. Transfusion with blood of the wrong type can be fatal, but this is unlikely to occur because blood is checked multiple times by medical personnel.