Transfusion is a relatively common act carried out in the hospital departments. It means a transfer of blood from a donor to a recipient. Seemingly banal process is complicated by the existence of blood groups and their inability to be mixed. From a certain point of view, blood transfusion is in fact a specific subtype of tissue transplantation.
Transfusion of "full blood" (blood cells and blood plasma) has significance in patients with deficiency of red blood cells (anemia). However, it is also possible to separate different components of blood and administer them individually. For example, people with decreased number of blood platelets may be administered special platelet transfusions. Clear blood plasma without any blood cells can be administered to adjust patient's internal environment in certain disorders of blood clotting.
Before transfusion, a blood sample should be taken from the patient and sent to the hematological laboratory to determined the blood type - A, B, AB, or 0 group and Rh positivity, or negativity. Based on the results, a transfusion set (blood unit) with compatible blood group is prepared. There is maximal effort to ensure that the patient gets the right blood unit - It must contain a special unique identification number with the name of the patient and clearly marked the blood group.
Transfusion should be always administered by a doctor. Transfusion is associated with an important bedside check that the blood unit is really compatible with patient's blood group. We usually take a small sample of blood from the blood unit and blood from the patient and mix these samples with special solutions. These solutions are able to precipitate certain blood groups. When the test confirms the compatibility, the blood unit is administered intravenously like normal infusions. At the beginning of administration, the blood is released faster and we call it as a biological test. When the patient begins to suffer from any unpleasant symptoms, we immediately stop the blood transfusion.
Disadvantages and risks
The greatest danger is in mixing of incompatible blood groups. In such case, the recipient's immune system evaluates the red blood of the donors as hostile foreign object and attacks them. Massive destruction of donor's red blood cells in the recipient's body leads to the onset of fever, chills, shortness of breath, chest pain and headache. The immune response can be so strong that it progresses to circulatory shock, acute renal failure and death. As mentioned above, when there is a suspicion of any problem, it is advisable to immediately stop the transfusion.
Historically, the transfusion carried a risk of transmission of certain severe infectious diseases such as some types of infectious hepatitis or AIDS. Nowadays, this risk is minimal to zero in developed countries thanks to strict control of blood units.