Although blood can be taken from one person and transfused directly into another, the usual routine today is for hospitals to maintain, collect and store blood for emergency use. The bank selects donors and determines the blood types of donors and recipients to assure safe and proper matching.
Autologous Blood Donation refers to transfusion wherein the donor and the recipient are the same. Some people usually do this before a surgical procedure in which the likelihood of needing a transfusion is high. Although not all doctors recommend this process because of some risk involved.
How blood is stored? The blood is stored with an anticoagulant, generally an acid-citrate-dextrose (ACD) solution composed of trisodium citrate, citric acid, dextrose, and sterile water.
Things to know about blood banking:
- Platelets also known as whole blood are typically pooled before transfusion and have a shelf life of five days. Platelets are stored at room temperature (20° - 24°C) and must be agitated.
- Red blood cells from blood stored for 21 days in ACD will survive in the recipient for about 100 days.
- If blood is not used within 21days, it is no longer suitable to use for transfusion.
- Stored blood that has remained unused for 21days may be reduced to plasma by centrifuging it to eliminate the red cells.
- Prolonged storage of whole blood can be achieved by freezing and maintaining it at very low temperatures-less than - 94°F (-70°C).
- Freezing and thawing of whole blood can greatly damage the red cells, but the use of solutions such as glycerol or dimethyl sulfoxide minimizes the damage, and red blood cells can be maintained in the frozen state for months without significant injury.
How often can a person donate blood? Usually 1 pint of blood is collected per individual. The body replenished the fluid lost during donation in 24hours, but it may take up to 2 months to replace the lost red blood cells. Therefore a person can only donate blood once every 2 months.
Plasma is the colorless liquid part of the blood in which the blood cells are suspended. It’s function includes; helping the body to maintain blood pressure, helps to balance the fluid-electrolyte and acid in the body, it also helps to transport wastes products and it helps to control bleeding when no coagulation factor is available. Plasma, rather than whole blood, is commonly used to treat disorders.
Plasma substitutes are now being used to restore the blood volume. These substitutes (polyvinylpyrrolidone (PVP) and dextran) have the advantages of being readily available at anytime, in any quantity, and at much less cost than human plasma. Dextran is a complex polysaccharide, whose clinical effect is considerable because it can produce an increase of blood volume that may last more than 24hours. However, there is no perfect artificial product that can replace human plasma.