Chandigarh, June 9
Dr J.G. Jolly, Emeritus Professor, PGI, has emphasised the need for the provision of more and advanced facilities for the preparation of blood components which will go a long way in ensuring quality as well as economy in India’s blood programme.
Currently, the facility for component preparation is available only at a few centres, he said in a talk with TNS. The introduction of this facility can amount to considerable amount of saving in blood requirements. “There is no doubt that this will entail extra expenditure for the equipment and technical expertise.
But it is high time that serious efforts are made by the health authorities to make this facility available. While the practice of dependence on voluntary donors helps to improve the quality and safety of blood, the introduction of component preparation will bring in economy in blood.”
Blood banking, he says, has acquired significance in recent years owing to advances in technology, improved preservation for blood, availability of blood plastic bags, screening for transmissible infections, facilities for cryobiology and better technological procedures for grouping, typing and cross-matching. Blood components have become a reality since the development of sterile integrated plastic bags. These advances have contributed towards providing safe blood and blood components to sustain support during complicated and prolonged operative procedures.
The safety of transfusion practice begins with the type of donation available. A firm resolve to depend entirely on voluntary blood donors is essential for maintaining the safety of blood and blood components. It is equally important to strictly adhere to the criterion of donor selection and only those who fulfil the minimum requirements should be entertained. For this, any healthy volunteer in the age group of 18 to 60 years, weighing above 50 kg, free from disease, especially transmissible infections such as AIDS, hepatitis, syphilis and malaria, can safely donate 400 ml of blood every three months. The practice of dependence on professional blood sellers is unethical and technically hazardous. Thus, for ensuring safe blood, total dependence on voluntary donors and complete elimination of professional blood sellers is of paramount importance for a blood transfusion service.
Dr Jolly says that the availability of improved blood containers, blood plastic bags instead of glass bottles and preservative anticoagulant solutions have helped better the processing techniques. Thus, the storage period has been increased from 20 days to 49 days. While preservative solution ACD has a shelf life of 21 days, CPDAI and ADSOL have a shelf life of 35 and 49 days, respectively. In fact, frozen blood can be stored for three to 10 years.
This is possible by the addition of cryo-protective agents like glycerol to blood collected in a standard anticoagulant and freezing the same at ultra low temperature, below minus 65°C. Whereas the whole blood and packed cells are stored in a refrigerator at 4°C, platelets are stored at room temperature and the coagulation factors like cryoprecipitate and fresh frozen plasma are stored in a deep freeze below minus 20°C.
The availability of sensitive blood group reagents, enzymes and electronic gadgets have been of tremendous help in standardising, grouping, typing and cross-matching techniques for ensuring perfect compatibility between the blood of the donor and the recipient of transfusions. There are a large number of antigens of different blood group system on the red blood cell, but clinically the most significant belong to ABO and Rh system which determine the blood group and Rh type of the individual.
Transfusion practice, based primarily on use of whole blood has been now replaced by substitution therapy or blood component therapy. In this case, the patient is administered only that constituent in which he or she is deficient. By this, the patient gets maximum benefit of minimum risk and the components thus saved are conserved for other patients.
Modern technology for blood collection in double, triple or quadruple plastic bags has made it possible to utilise single donor’s blood for several patients suffering from different diseases.
A routine blood bank equipped with a refrigerated centrifuge, freezer, refrigerated water bath, refrigerator and plastic bags, can prepare all components. The most frequently used component consists of packed red blood cells and can be prepared by expressing the plasma from whole blood in which the red cells have been allowed to settle. Another component that is prepared frequently is platelet concentrate. Platelets must be separated from whole blood immediately after collection and constantly agitated during storage at 22°C to prevent aggregation. The plasma recovered as a result of preparation of paced cells and platelets may be frozen quickly and stored up to one year at minus 30°C, as a source of Factor VIII and other coagulation factors. Such plasma is popularly known as fresh frozen plasma (FFP).
Cryoprecipitate is prepared after freezing the plasma and thawing it at 4°C is an even richer source of Factor VIII. This can be removed and preserved, after which the remaining material can be fractionated into albumin, gamma globulin and other fractions.
