Blood transfusion is the process of transferring blood or blood-based products from one person into the circulatory system of another. Blood transfusions have many indications as mentioned below:
· Blood transfusions can be life-saving in some situations, such as massive blood loss due to trauma, or can be used to replace blood lost during surgery.
· Blood transfusions may also be used to treat a severe anemia or thrombocytopenia caused by a blood disease.
· People suffering from hemophilia or sickle-cell disease may require frequent blood transfusions.
Before a blood transfusion, a series of procedures need to be done to establish the proper selection of blood for the patient. Basically, those procedures try:
· to establish ABO and Rh compatibility between donor and recipient and
· to rule out the existence of antibodies in the recipient’s serum, which could react with transfused red cells.
To establish the ABO and Rh compatibility between donor and recipient, both the recipient and the blood to be transfused are typed. The most direct way to detect antibodies in the recipient’s serum that could cause hemolysis of the transfused red cells is to test the patient’s serum with the donor’s cells (major cross-match). The minor cross-match, which consists of testing a patient’s cells with donor serum is of little significance and rarely performed, since any donor antibodies would be greatly diluted in the recipient’s plasma, and rarely, it causes clinical problems.
Universal recipient: It is an ABO blood group individualwhose red blood cells express antigens A and B, but whose serum does not contain anti-A and anti-B antibodies. Thus, red blood cells containing any of the ABO antigens, i.e., from an individ-ual with type A, B, AB, or O, may be transfused to the universal recipient without inducing a hemolytic transfusion reaction.
It is best if the universal recipient is Rh positive, i.e., has the RhD antigen on the erythrocytes to avoid developing a hemo-lytic transfusion reaction. However, blood group systems other than ABO may induce hemolytic reactions in a universal recipi-ent. Thus, it is best to use type-specific blood for transfusions.
Universal donor: It is a blood group O RhD-negative individ-ual whose erythrocytes express neither A nor B surface antigens. This type of red blood cell fails to elicit a hemolytic transfusion reaction in recipients with blood group A, B, AB, or O. However, group O individuals serving as universal donors may express other blood group antigens on their erythrocytes that may induce hemolysis. It is preferable to use type-specific blood for transfusions, except in cases of disaster or emergency.
Complications of Blood Transfusion
Transfusion reaction is the major immunological complication following incompatible blood transfusion. Other transfusion reactions may be caused due to factors other than incompat-ibility, such as a person being hypersensitive to some allergens present in the blood. Transmission of infectious agents through blood is the most important complication. These include:
· Viruses, such as human immunodeficiency viruses I and II (HIV I and II), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), and cytomegalovirus (CMV);
· Bacteria, such as Treponema pallidum and Leptospira interrogans; and
· Protozoa, such as Toxoplasma gondii, Leishmania donovani, and Plasmodium species.
· Transmission of HIV I and II, HBV, and HCV, which is a major concern.