Transfusions

The main features in which the Radford process differs from the batch operation are in thermal dehydration and compounding. Water-wet nitrocellulose on a continuous vacuum belt filter is vacuum-dried followed by hot air transfusion (80°C) to reduce the moisture to less than 2%. After cooling, alcohol is sprayed on the nitrocellulose to a concentration of 15—20%. The alcohol-wet nitrocellulose is then transferred from a surge feeder to a compounder by a continuous weigh-belt along with the other ingredients of the composition, which are also weighed and added automatically. 

Whole blood is seldom used ia modem blood transfusion. Blood is separated into its components. Transfusion therapy optimizes the use of the blood components, using each for a specific need. Red cell concentrates are used for patients needing oxygen transport, platelets are used for hemostasis, and plasma is used as a volume expander or a source of proteins needed for clotting of the blood. 

The discovery in 1900 of the existence of blood groups, together with improved understanding of the importance of sterile conditions, paved the way to modem blood transfusion therapy. In 1915, the feasibiUty of storage of whole blood was demonstrated. During World War I, the optimal concentration of citrate for use as an anticoagulant was determined. This anticoagulant was used until 1942, when the acid—citrate—dextrose (ACD) solution was developed. 

A new field of transfusion medicine, cell therapy, has developed with the better understanding of the function of different cell types ia the body. In cell therapy, various malignancies are treated by transfusion of specific cell types from blood. Therefore, more and more specialized methods for separating blood iato the various components are required. 

Red Blood Cells. Red blood cells (RBC) transport and deUver oxygen and carbon dioxide between the tissues and lungs. Red blood cell transfusions iacrease the oxygen carrying capacity ia anemic patieats. 

The red cells also may be filtered to reduce the white cell content. This technique is needed if there is a chance of the patient developing graft versus host disease (GvHD), ie, transfused white cells attack the cells of the patient. 

Contamination of blood products with lymphocytes can lead to transfusion-induced reactions ranging from a mild fever to severe reactions such as alloimmunization and graft versus host disease (GvHD), in which the transfused lymphocytes (graft) survive the defensive immune reaction of the patient (host) and start a reaction which destroys the cells of the host. The patient also may develop an immune response to the human leukocyte antigen (HLA) type of the graft s cells and reject all platelet transfusions that do not match their own HLA system. The HLA system, found on blood platelets and lymphocytes, is more compHcated than, but similar to, the ABO blood group system of red cells. 

They release adenosine diphosphate [58-64-0 (ADP) and thromboxane [57576-52-0] which results in vascular contraction and, indirectiy, in the formation of fibrin clot. Platelet transfusions are indicated for patients with thrombocytopenia, ie, a shortage of healthy platelets or thrombocytopathy, ie, platelet malignancy associated with spontaneous hemorrhages. 

Transfusion-induced autoimmune disease has been a significant complication in the treatment of patients who require multiple platelet transfusions. Platelets and lymphocytes carry their own blood group system, ie, the human leukocyte antigen (HLA) system, and it can be difficult to find an HLA matched donor. A mismatched platelet transfusion does not induce immediate adverse reactions, but may cause the patient to become refractory to the HLA type of the transfused platelets. The next time platelets with an HLA type similar to that of the transfused platelets are transfused, they are rejected by the patient and thus have no clinical efficacy. Exposure to platelets originating from different donors is minimized by the use of apheresis platelets. One transfusable dose (unit) of apheresis platelets contains 3-5 x 10 platelets. An equal dose of platelets from whole blood donation requires platelets from six to eight units of whole blood. Furthermore, platelets can be donated every 10 days, versus 10 weeks for whole blood donations. 

Filtration Filtration (qv) is appHed in blood cell separation to remove leukocytes from ted blood cell (RBC) and platelet concentrates. Centtifugational blood cell separators do not reduce white blood cells (WBC) in red cell and platelet products sufficiently to avoid clinical complications such as GvHD and alloimmunization. A post-apheresis filtration step is needed to further reduce the WBC load. Modem filters are capable of a 3-log reduction in white cell contamination of the blood product, eg, apheresis single-donor platelet units having a typical white cell contamination of 5 x 10 white cells in 4 x 10 platelets can be reduced to a 5 x 10 white cell contamination, a sufficiently low number to avoid severe transfusion reactions. 

Blood transfusion is highly regulated worldwide by government institutions, such as the USFDA, and through associations of blood banks, such as the American Association of Blood Banks (AABB). Strict regulations on good manufacturing practices (GMP) have been estabhshed to ensure maximum safety of the transfused products. 

J. P. Dutcher, "Platelet Transfusion Therapy in Patients with Malignancy," in J. P. Dutcher, ed.. Modem Transfusion Therapy, CRC Press, Boca Raton, Ha., 1990. 

J. P. Dutcher, "Granulocyte Transfusions in Patients with Malignancy," in Ref 5. 

C. A. Kasparin and M. Rzasa, eds.. Transfusion Therapy M Practical Approach, AABB, Arlington, Va., 1991. 

H. F. TasweU and A. A. Piaeda, eds.,Mutohgous Transfusion andHemotherapj, Blackwell Scientific, Boston, Mass., 1991. 

Full details of this work were pubHshed (6) and the processes, or variants of them, were introduced in a number of other countries. In the United States, the pharmaceutical industry continued to provide manufacturing sites, treating plasma fractionation as a normal commercial activity. In many other countries processing was undertaken by the Red Cross or blood transfusion services that emerged following Wodd War II. In these organisations plasma fractionation was part of a larger operation to provide whole blood, blood components, and speciaUst medical services on a national basis. These different approaches resulted in the development of two distinct sectors in the plasma fractionation industry ie, a commercial or for-profit sector based on paid donors and a noncommercial or not-for-profit sector based on unpaid donors. 

Guidelines for the Blood Transfusion Services in the United Kingdom, National Institute For Biological Standards and Control, Potters Bar, 1992. 

E. Eeldman and co-workers, ia G. Rock and M. J. Segatchian, QualityMssurance in Transfusion Medicine, Vol. II, CRC Press, Boca Raton, Ela.,... 

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