Transfusion is the process of giving whole blood or one of its components to a patient who is ill or injured. According to the National Heart, Lung and Blood Institute, almost 5 million Americans need blood transfusions each year to treat various illnesses, as well as to replace blood lost through surgery or traumatic injury.
Blood is donated by healthy volunteers and is tested for blood-borne disease before distribution to clinics and hospitals. Whole blood is made up of four components: platelets, red blood cells, cryoprecipitates and plasma. Each pint of donated whole blood is usually broken down into two or three of those components, so each donation can save up to three lives.
Although some patients receive whole blood, especially in emergency situations, the more common practice is to transfuse only the component that is needed to treat the particular situation.
Trauma
Traumatic injuries sustained in car accidents, war or natural disasters may require transfusion to replace lost blood volume. The average adult's blood volume is about 10 pints, but, explains the American Red Cross, a car accident victim may require as many as 100 pints. Whole blood, plasma or red blood cells may be transfused in these situations.
Surgery
Patients who lose blood during surgery may receive blood transfusions--usually red blood cells or platelets--during or after the procedure. One-third of all heart surgery patients, reports the National Heart, Lung and Blood Institute, require a transfusion. Some patients scheduled to undergo a planned procedure may choose to have pints of their own blood collected for use during or after the surgery if their surgeon agrees.
Cancer
The American Cancer Society states that cancer patients may require transfusions of red blood cells for anemia--low red blood cell count--because of internal bleeding or the involvement of certain organs that affect the blood cells. Bone marrow cancers, including leukemia, cause low blood counts, because they crowd out the normal blood-making cells. Cancer patients may also require transfusions because of anemia caused by chemotherapy, a bone marrow transplant or radiation.
Bleeding Disorders
Platelets and clotting factors help stop bleeding, so patients with bleeding disorders may bleed excessively when injured or may bleed internally. Doctors treat patients with clotting factor disorders, including hemophilia, with the missing or defective blood component.
Other Illnesses
Patients with diseases that interfere with the body's ability to make blood or its components, including severe infections, liver disease and kidney disease, may require transfusion. Patients with sickle cell disease, a rare, inherited disorder, may require frequent transfusions throughout their lives.
