By Jen Christensen
Posted: Tuesday, March 13, 2007 at 9:28 AM
Blood Transfusion
According to the American Association of Blood Banks, nearly 29 million units of blood were transfused in 2004. Blood often comes from a donor (called
allogeneic blood donation) or may be donated ahead of time by the patient and banked for later use (
autologous donation).
Allogeneic blood is usually separated into several components.
Red blood cells carry oxygen to the tissues and carbon dioxide back to the lungs.
Platelets are the cells that control bleeding.
Plasma is the liquid portion of the blood. It contains water, ions, sugar, hormones and protein.
Cryoprecipitate contains clotting factors that have been removed from plasma.
Risks of Blood Transfusion for Surgery Patients
Transfusions are sometimes performed to increase the availability of oxygen to the tissues or replace large amounts of blood lost during surgery. However, the procedure has some risks. Transfused blood that comes from a donor must match the same blood type as that of the recipient. If a
mismatched blood type is given, the patient’s body may react – attacking the donor cells and increasing the risk of kidney failure, shock or death. Transfusion errors are rare in the U.S. Researchers estimate about one in every 14,000 units of donated blood is given to the wrong person. But about 10 percent of those who react to the blood incompatibility die.
There is a risk that donated blood may contain some type of
infectious disease. Several viruses have been found in the nation’s blood supply, such as HIV, hepatitis A, B, and C, malaria, syphilis, cytomegalovirus, herpes virus, Epstein-Barr virus, West Nile virus and Creutzfeldt-Jacob virus. While donors and blood are screened for infectious diseases, there is still a very small chance the virus may not be detected. In addition, new viruses or infectious diseases may emerge for which there are no screening tools.
Transfusion-associated lung injury occurs in about one out of every 5,000 transfusions. Patients develop acute respiratory distress within about four hours after transfusion, causing breathing difficulties, pulmonary edema and reduced levels of oxygen to the tissues.
In addition, researchers have found after 15 days of storage, red blood cells lose their ability to carry oxygen and become less flexible (which affects their ability to pass through the narrow capillaries). One study found cardiac patients who received red blood cell transfusions were more likely to experience post-operative atrial fibrillation. Another study found coronary artery bypass patients who received a blood transfusion were more likely to develop an infection than those not receiving a transfusion. In addition, the transfusion patients were 5.6 times more likely to die within 100 days of the surgery.
Reducing the Need for Blood Transfusions for Surgery Patients
As health concerns regarding blood transfusion become more apparent, an increasing number of hospitals are using techniques to reduce the need for transfusion in surgery patients. The trend is called "Bloodless Medicine."
There are several different methods that can be used. Patients may be able to
pre-donate blood and use it later if needed. This isn’t an option for everyone because some patients are too sick to donate their blood ahead of time or need surgery unexpectedly. If blood is donated too soon in advance, the red cells lose their ability to carry oxygen.
Patients who can’t pre-donate can take steps to boost their own blood reserves, reducing the effects of blood loss on the body.
Erythropoietin is a hormone that stimulates the bone marrow to make more red blood cells.
Supplementation with iron, hormones, vitamin B12, folic acid and vitamin C may also help build levels of blood cells and improve wound healing. Lori Heller, M.D., Blood Management Program Director at Swedish Medical Center in Seattle....
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