Blood Transfusions

A blood transfusion is giving a patient blood cells from a donor. Many patients with diseases that may be treated with a bone marrow or cord blood transplant get blood transfusions during their treatment. This is because in many of these diseases, the bone marrow does not make enough red blood cells, white blood cells and platelets. In addition, these diseases are often treated with chemotherapy, which can also reduce the numbers of blood cells.

The purpose of transfusions

Transfusions are used to keep your number of blood cells at a safe level. They may be used before, during or after other treatments.

Red blood cells

You may get a red blood cell transfusion if you have too few red blood cells (anemia). Anemia causes weakness and tiredness. In severe cases, it can cause shortness of breath or a rapid heartbeat. To measure your level of red blood cells, a doctor checks your hemoglobin level. Transfusions are usually used when the hemoglobin level is less than 8 grams per deciliter. Sometimes instead of a transfusion, you may get a red blood cell growth factor — a drug that helps your body make more red blood cells. This growth factor is called erythropoietin (Procrit^®, Epogen^®, Aransep^®).

Platelets

You may get a platelet transfusion if you have too few platelets. You need platelets to prevent or stop bleeding and bruising. Doctors prescribe platelet transfusions to keep the platelet count above 10,000 to 20,000 (per cubic millimeter), or if you are bleeding because of low platelet counts. Transfused platelets last only two to three days. Until your body begins making its own platelets, you might get platelet transfusions two or three times a week.

White blood cells

White blood cell (granulocyte) transfusions are rare. This is because the granulocytes last only a few hours in the bloodstream. Donated white blood cells must be used right away and do not last long. White blood cell transfusions can also cause fevers or infections. Instead, you may get a growth factor that helps the body make more white blood cells. A common example is filgrastim (Neupogen^®).

What to expect during transfusions

If you need a transfusion, you will get the blood cells through tubing connected to a needle in your vein. You will most likely get the transfusion in a hospital or an outpatient clinic. A transfusion takes about two to three hours for each unit of blood cells.

For a red blood cell transfusion, the blood you get must match or be compatible with your blood type. For platelet transfusions, matching blood types is less important. Even so, you will usually get a matching blood type, especially if you may need many transfusions.

If you have had a bad reaction to previous transfusions, you will get medicine to help prevent another reaction. Otherwise, you will probably not get any medications with your transfusion.

Risks and side effects

Most patients do not have any side effects from blood transfusions. About 1 to 2% of transfusions may cause fever and chills or an allergic reaction, such as hives. If you have had these side effects during past transfusions, you may get medicine before your transfusion to help reduce any reaction. In addition, white blood cells are usually filtered out of red blood cell and platelet transfusions, because the white blood cells can cause fever and chills.

If you get a lot of transfusions, your body may develop antibodies (immune cells) that can react against donated blood cells so that transfusions do not work well. For example, the platelet count will not go up much after a platelet transfusion. If this happens, you may need to get blood cells that match you at a more detailed level than a simple blood type.

For patients who have a weak immune system because of their chemotherapy or disease, the donated blood cells may be treated with radiation. This is to prevent a complication called graft-versus-host disease (GVHD). In GVHD, some of the donated blood cells (the lymphocytes) attack the patient's body. GVHD after a blood transfusion is rare but can be very serious. (GVHD is also a possible complication of a bone marrow or cord blood transplant using donated cells.)