Blood transfusion is a medical procedure in which blood or components of it, such as blood cells or plasma, are administered to a patient. Because transfusion can have serious risks and side effects, despite modern technology and testing procedures, it should only be performed in emergencies or in cases of chronic hematopoiesis disorders, and in any case it should only be ordered and carried out by a physician.
What is a blood transfusion?
Blood transfusion is a medical procedure in which blood or components thereof, such as blood cells or plasma, are administered to a patient. A blood transfusion is an intravenous infusion in which blood components or, as was once common, whole blood are transferred into the organism. The administration of blood components or blood is always ordered and performed by a physician. The blood or blood components enter the bloodstream directly by means of a venous cannula. Donated blood is divided into its components (red blood cells, white blood cells, platelets, and plasma) in so-called blood banks, where it is stored.
Function, effect, and goals
Transfusion of blood components occurs either in emergencies or when blood formation disorders are detected. The most common hematopoietic disorder requiring blood transfusion is severe anemia, or anemia. Sometimes an exchange transfusion is required, for example in the case of blood group incompatibility between mother and child, or in the case of a hemolytic crisis. Depending on the blood donor, a distinction is made between a foreign blood donation and an autologous blood donation. Autologous blood donation is the safest method of blood transfusion, because it clearly excludes the possibility of infection transmission or incompatibility reactions. Autologous blood donation is particularly recommended in the event of a planned operation. In the case of a foreign blood donation, the important prerequisite for a transfusion is the compatibility of the blood groups of the donor and recipient. Ideally, both the blood groups and the rhesus factors of both match. If this is not the case, then the following rules apply: Blood type 0 Rhesus negative is universal donor, and patients with blood type AB Rhesus positive can receive blood of any blood type. If the different characteristics of the blood groups were not taken into account, life-threatening consequences would result. The AB0 blood group system and the rhesus factor require special attention. Blood group compatibility is complex and therefore varies depending on what blood components are being transferred. In the case of red blood cell transfusion, the patient with blood group 0 may be given only the red blood cell concentrate from a donor with blood group 0, while in the case of plasma transfusion, his blood group is compatible with all four blood groups. In contrast to whole blood transfusion, the measures used nowadays, namely transfusion of blood components, have the advantage that the patient receives only those components of the blood that he actually needs. In addition, blood components can be stored longer than whole blood. Different components of the blood are transferred for different needs, such as red blood cells for anemia or platelet concentrates for bleeding tendencies.
Risks and dangers
Common side effects of a blood transfusion include chills, a drop in blood pressure, and fever. In rare cases, circulatory shock occurs. Another side effect of blood transfusion is iron overload. This occurs mainly with long-term transfusion therapies. One of the risks of blood transfusion is the transmission of bacteria and viruses. Thanks to modern molecular biology methods, the risk of transmission of life-threatening viruses is very low. These testing methods are relatively young, spreading only since the mid-1980s. Before that, many patients became infected with HIV through blood transfusion. When blood is mixed up, an acute or delayed hemolytic transfusion reaction occurs. Non-hemolytic transfusion reactions include allergic reactions and abnormal immune system reactions that affect the whole organism. White blood cells can cause a graft-versus-host reaction in immunocompromised patients.However, there are measures that can be taken to reduce the risks of a graft-versus-host reaction, such as irradiation of blood products. According to a 2007 study, medical experts believe that even if the donor develops cancer after donating, there is no increased risk of cancer for the recipient. However, another study from 2009 refutes this theory.