At present time there are a number of blood components that are more suitable for transfusion purposes than is whole blood. In order to make maximum use of blood, it is necessary that there be close cooperation between the blood bank personnel and those responsible for patient care

Langdell, Robert D.

VCU Scholars Compass

Utilization of Blood and Its Products* ROBERT D. LANGDELL, M.D. Professor of Pathology, School of Medicine, University of North Carolina, Chapel Hill The development of a system of plastic bags connected by integral tubing for the collection, processing and storage of blood has made it pos-sible for selective transfusion of appropriate blood components. It is now possible to select the blood component that will correct a patient's physiologic deficiency. This has resulted in better patient care and in better utilization of blood since a single unit of blood can be used to supply erythrocytes for an anemic patient, platelets for a patient with thrombocytopenia and factor VIII concentrate for a patient with hemophilia. In order to utilize blood and its components optimally, there must be a close working arrange-ment between the blood bank personnel and the clinical staff. At the time when blood is obtained from a donor, a decision should be made con-cerning how the blood will be used. Several of the components can be prepared only from fresh blood. The equipment, supplies and personnel time should be used to produce the maximum benefit to the recipients of the blood. Although each unit of blood could be separated into several useful com-ponents, it is a wasteful procedure if the com-ponents are not used. Each institution must deter-mine its need for blood and blood components . Those responsible for the operation of the blood bank should not make unilateral decisions about the preparation of blood components and the clinical staff should not make unilateral decisions about the use of blood components. Packed Red Blood Cells. When blood is col-lected in the proper closed bag system, it is possible to remove much of the plasma after sedimentation or centrifugation without opening the container. The resulting packed red blood cells remain viable ,:, Presented by Dr. Langdell at the 44th Annual Mc-Guire Lecture Series, March 23 , 1973, at the Medical Col-lege of Virginia, Richmond . 298 for transfusion purposes for 21 days when stored under standard conditions. The obvious advantage of transfusing packed red blood cells is that the circulating erythrocyte mass of the recipient can be increased without increasing the circulating plasma volume. This minimizes the possibility of circulatory overload. It has been estimated that up to 80 percent of the transfusions should be in the form of packed red blood cells (2) . Along with the plasma, most of the sodium added in the anticoagulant solution is removed. This can be an important factor when transfusions are necessary in patients requiring limited sodium in-take. In addition to the excessive amounts of elec-trolytes and citric acid, the plasma contains anti-bodies. One of the dangers in the universal donor concept is that the plasma of group O individuals contains antibodies against group A and group B cells. These antibodies are removed along with the plasma. Although type specific compatible erythrocytes are the treatment of choice, in an emergency situation when such blood is not avail-able, group O packed red blood cells are an ac-ceptable form of therapy. Factor VIII Concentrates. The treatment of hemophilia with plasma rather than whole blood was an early form of component therapy. It was found that plasma contains the material lacking in hemophilia and except for the occasional patient with anemia, whole blood is seldom needed for the treatment of hemophilia. Although the anti-hemophilic factor in plasma is relatively labile, it can be maintained in plasma stored below -18 °C. Until relatively recently, plasma removed from whole blood within a few hours of collection and then promptly frozen was the only available source of factor VIII for human use. Because of the rela-tively small amount of antihemophilic activity in plasma, large amounts of fluid had to be infused MCV QUARTERLY 9(4) : 298-300, 1973 LANGDELL: UTILIZATION OF BLOOD to significantly increase the circulating level in the patient. In addition, the infused activity was re-tained in the circulation for only a short period of time (4). Thus, therapy was restricted to the amount of fluid that could be infused without caus-ing overload. In 1965, Pool and her associates (5) reported that when frozen plasma was thawed slowly, a poorly soluble, gelatinous precipitate was formed. This material, called cryoprecipitate, was found to contain a considerable amount of the antihemo-philic activity of plasma. Thus, it became possible to concentrate and collect factor VIII of plasma in a closed bag system. The resulting material con-tains, on the average, about half of the antihemo-philic activity of the original plasma and in a relatively small volume. Although the treated plasma can be returned to the cellular component and used as whole blood, most have found it better to utilize the plasma for other purposes. The residual plasma can be used for all conditions where plasma is indicated other than for the treatment of hemophilia. Platelet Concentrates. Fresh whole blood con-tains viable platelets which will function when transfused. When platelets are needed to control bleeding in a patient with thrombocytopenia, how-ever, a large amount of blood must be infused to increase the platelet level in the circulation. Platelets can be separated from whole blood and transfused in a relatively small volume. Platelets have a specific gravity of 1.040 while the specific gravity of erythrocytes is about 1.095 (3). Since platelets are lighter than erythrocytes, the red blood cells can be sedimented by low speed centrifugation while the platelets remain suspended in plasma. In this way platelets can be separated from whole blood in a closed bag system. Platelets, however, have a very short shelf life and to be effective must be infused promptly after collection. Although platelets lose viability rapidly, approxi-mately half of the recovered platelets are still effec-tive after 72 hours of storage. Most workers, though, feel that platelets should be used within the first 48 hours after collection. Although there is some evidence that room temperature storage has some advantages, it is felt that best results are obtained when platelets are stored at 4 °C. Additional studies of storage are necessary to determine optimal conditions ( 1) . Platelets can be given along with the plasma 299 as platelet rich plasma. It is usually necessary, however, to give the platelets recovered from six units of blood to achieve the desired effects and it is normally not desirable to give this amount of fluid. The usual practice is to concentrate the platelets by centrifugation and remove all but ap-proximately 30 ml of plasma. Following centrifuga-tion, it may be difficult to resuspend the platelets. Gentle agitation after storage for about one hour has been found to result in a satisfactory product. It is generally recommended that platelets be in-fused through a filter to remove any large aggregates. Plasmapheresis. One of the limitations of ob-taining blood is that approximately six-to-eight weeks are required for the regeneration of eryth-rocytes. For this reason, the interval between in-dividual donations of blood should be at least eight weeks. The regeneration of the fluid volume and plasma proteins is more rapid. With a series of bags connected by integral tubing, it is possible to withdraw blood from a donor, separate the eryth-rocytes from the platelet rich plasma and return the erythrocytes to the donor. This process, called plasmapheresis, can be repeated at frequent intervals without danger to the donor. This technique has several advantages when the needs for platelets and plasma are great. A relatively small number of donors can supply con-siderable amounts of platelets and plasma. There is increasing evidence that when platelets are given over a prolonged period, antibodies to platelets develop in the multitransfused patient. These anti-bodies appear to be directed against the histo-compatibility antigens of the HL-A system. Those institutions which use platelet transfusions on a long-term basis have found that best platelet sur-vival occurs when there is an HL-A compatibility between donor and recipient. It is generally felt that if a series of platelet transfusions are required, it is best to obtain platelets by plasmapheresis from a few histocompatible donors rather than utilizing platelets from a number of random blood donors (7). Frozen Red Blood Cells. With currently avail-able techniques, erythrocytes retain sufficient via-bility for transfusion purposes for only 21 days. For this reason blood supplies must be continuous and the blood bank must be able to predict its needs so that sufficient blood will be available and yet there will not be wastage due to excessive 300 amounts of erythrocytes lost by out-date. An ob-vious solution would be to develop a method of preservation of blood for longer periods. A number of chemical additives have been used in an attempt to prolong the viability of erythrocytes. The most promising has been adenine (6). With the addition of adenine at the time of collection, there is evidence that erythrocytes re-main viable up to 40 days under the usual storage conditions. At the present time, however, there is not sufficient evidence to be certain of the safety of this material for human use. Other workers have demonstrated that eryth-rocytes suspended in cryoprotective solutions retain viability almost indefinitely when stored at low temperatures. Before the erythrocytes can be in-fused , the cryoprotective materials must be removed. The supplies and equipment necessary for prepara-tion, storage and washing make this technique rather expensive. Although the techniques are practical, the cost for a unit of such blood is almost pro-hibitive for routine use. If methods can be de-veloped to decrease the cost, there are many ad-vantages to such a technique. Leukocyte-Poor Blood. There are many known antigens associated with erythrocytes, but most of these are only occasionally of clinical significance. For practical purposes, it is only necessary to routinely test for ABO and Rh antigens. In a similar way there are a number of antigens as-sociated with leukocytes, but these are usually of little clinical significance. In multitransfused pa-tients, however, the leukocytes may cause reactions. To prevent these reactions it may be necessary to give leukocyte-poor blood. Recently it has been recognized that leukocyte antigens may have an adverse effect on organ transplantation. It has been suggested that patients with chronic renal disease who may be candidates for renal transplantation should be given only leukocyte-poor blood. The specific gravity of granulocytes is 1.087-1.092 and the specific gravity of lymphocytes is 1.070 ( 3). Thus differential centrifugation to prepare leukocyte-poor erythrocytes is rather difficult. There LANGDELL: UTILIZATION OF BLOOD are techniques by which most of the leukocytes can be separated from erythrocytes but these techniques are tedious and time consuming. In order to remove the leukocytes and their antigens it is necessary that fresh blood be used. In those institutions that have a frozen blood program, it has been found that this preparation is an excellent source of leukocyte-poor erythrocytes. Summary. At the present time there are a number of blood components that are more suitable for transfusion purposes than is whole blood. In order to make maximum use of blood, it is neces-sary that there be close cooperation between the blood bank personnel and those responsible for patient care. REFERENCES 1. ASTER, R . H . AND BECKER, G. A. Platelet preservation. In : Transfusion and Transplantation, ed. P . S. Schmidt, Am. Assoc. of Blood Banks, 1972, p. 35 . 2. GREENWALT, T. J. AND PERRY, s. Preservation and utili-zation of the components of human blood. In: Hema-tology, Vol. VI, eds. E . B. Brown and C . V . Moore (Grune & Stratton, New York, 1969) , p. 148. 3. HUESTIS, D. w., BOVE, J . R . AND BUSCH, S. Practical blood transfusion . (Little Brown & Co. Boston, 1969), p. 300. 4. LANGDELL, R. D., WAGNER, R. H. AND Bil.INKHOUS, K. M. Antihemophilic factor (AHF) levels following transfu-sion of blood, plasma and plasma fractions. Proc. Soc. Expt. Biol. Med. 88:212, 1955. 5. PooL, J . G . AND SHANNON, A. E . Production of high-potency concentrates of antihemophilic globulin in a closed-bag system. N . Engl. ! . Med. 273 : 1443, 1965. 6. SIMON, E. R. , CHAPMAN, R . G. AND FINCH, C . A . Adenine in red cell preservation. /. Clin . Invest. 41 :351, 1962. 7. YANKEE, R. A., GRUMET, F . C . AND ROGENTINE, G. N . The selection of compatible platelet donors for refractory patients by lymphocyte HL-A typing. N. Engl. !. Med. 281 : 1208, 1969. 

Utilization of Blood and Its Products

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Utilization of Blood and Its Products

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