Blood transfusion

The Blood transfusion is a medical procedure in which blood or components thereof, such as blood cells or plasma, are administered to a patient. Since the transfusion can have serious risks and side effects despite modern technology and test procedures, it may only be carried out in emergencies or in the case of chronic blood formation disorders and in any case only be ordered and carried out by a doctor.

What is a blood transfusion?

Under one Blood transfusion one understands an intravenous infusion, in which blood components or, as was usual in the past, whole blood are transferred into the organism. The administration of blood components or blood is always ordered and carried out by a doctor.

The blood or blood components enter the bloodstream directly through a venous cannula. Donated blood is divided into its components (red blood cells, white blood cells, blood platelets and blood plasma) in so-called blood banks and stored here.

Function, effect & goals

Blood components are transfused either in emergencies or when blood formation disorders are detected. The most common hemorrhage disorder, the one Blood transfusion what is required is severe anemia, also known as anemia.

Sometimes an exchange transfusion is necessary, for example if there is a blood group incompatibility between mother and child, or if there is a hemolytic crisis. Depending on the blood donor, a distinction is made between donating blood from another person and donating one's own blood. An autologous blood donation is the safest method of a blood transfusion, because it clearly rules out the transmission of infections or intolerance reactions. An autologous blood donation is particularly recommended for 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, the following rules apply: Blood group 0 rhesus negative is a universal donor, and patients with blood group AB rhesus positive can receive blood of any blood group. If the various characteristics of the blood groups were not taken into account, life-threatening consequences would arise. 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. When transfusing red blood cells, the patient with blood group 0 can only receive the red blood cell concentrate from a donor with blood group 0, while with a blood plasma transfusion his blood group is compatible with all four blood groups.

In contrast to whole blood transfusion, the measures used today, namely the transfusion of blood components, have the advantage that the patient only receives the components of the blood that he actually needs. In addition, blood components can be stored longer than whole blood. When the need arises, different components of the blood are transferred, such as red blood cells for anemia or platelet concentrates for people with a tendency to bleed.

Risks & dangers

General side effects of a Blood transfusion are chills, a drop in blood pressure and a fever. In rare cases circulatory shock occurs. Another side effect of blood transfusion is iron overload. This occurs especially with long-term transfusion therapies.

One of the risks of blood transfusion is the transmission of bacteria and viruses. Thanks to modern molecular biological methods, the risk of transmission of life-threatening viruses is very low. These test methods are relatively new; they only became widespread since the mid-1980s. Before that, many patients became infected with HIV through blood transfusions. If the blood units are mixed up, an acute or delayed haemolytic transfusion reaction occurs.

The non-hemolytic transfusion reactions include allergic reactions and pathological reactions of the immune system, which affect the whole organism. The white blood cells can cause a graft-versus-host reaction in immunocompromised patients.

However, there are measures that can be used to reduce the risk of a transplant-versus-host reaction, such as irradiating blood products. According to a study from 2007, medical professionals assume that there is no increased cancer risk for the recipient even if the donor develops cancer after donating. Another study from 2009 refutes this theory.