Blood products
Last reviewed: 23.04.2024
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Transfusion of whole blood improves oxygen capacity of blood, volume recovery, coagulation factors and was previously recommended for massive blood loss. However, since component therapy is more effective, whole blood is not currently used for transfusion therapy.
Erythrocyte-containing media are a component of choice if it is necessary to increase the level of hemoglobin. Indications for transfusion depend on the patient's condition. Oxygen transport function of blood can be adequate even with hemoglobin content of 70 g / l in healthy people, but transfusions may be necessary at a higher hemoglobin level in patients with pulmonary heart failure or continuing bleeding. A single dose of erythrocyte mass raises the hemoglobin level in an adult patient by an average of 10 g / L and a hematocrit level of 3% from the pre-transfusion level. If it is necessary to replenish only the volume of blood, blood substitutes or blood substitutes are usually used in combination with the erythrocyte mass. In patients who have multiple group antibodies or antibodies to common erythrocyte antigens, a rarely used frozen erythrocyte mass is used.
Washed erythrocytes are free of almost all traces of plasma, most leukocytes and platelets. They are usually prescribed to patients with marked reactions to plasma transfusion (eg, severe allergy, paroxysmal nocturnal hemoglobinuria, or immunization with IgA).
Erythrocytic mass with leukocyte depilation is prepared with the help of special filters that remove £ 99.99% of white blood cells. It is prescribed to patients who have hemolytic febrile transfusion reactions, with exchange transfusions, patients who need cytomegalovirus negative blood in its absence, and to prevent platelet alloimmunization.
Freshly frozen plasma (FFP) is an unconcentrated source of all clotting factors, except for platelets. Indications for its transfusion are correction of bleeding caused by a deficiency of plasma factors, when substitution of specific factors is not available, multifactorial deficiency states [eg, massive transfusions, disseminated intravascular coagulation (DVS), liver pathology] and warfarin overdose. Transfusion of FFP can be used in addition to erythrocyte mass, if necessary, for exchange transfusion. Transfusion of FFP should not be used for simple volume reimbursement.
Cryoprecipitate is a concentrate prepared from SFP. Each dose of cryoprecipitate usually contains about 80 units of factor VIII, von Willebrand factor, about 250 mg of fibrinogen, in addition it contains fibronectin and factor XIII. Although cryoprecipitate was originally used to treat hemophilia and von Willebrand disease, it is used in the same way as the source of fibrinogen in acute DIC bleeding syndrome, in the treatment of uremic bleeding, in cardiac surgery (fibrin glue), obstetric complications such as placental abruption and HELLP- syndrome (hemolysis, increased hepatic enzymes and low platelet count), with factor XIII deficiency. In general, cryoprecipitate should not be used for other indications.
Granulocytes can be transfused in the case of sepsis in patients with severe persistent neutropenia (leukocytes <500 / μL) with no response to antibiotic therapy. Granulocytes are used within 24 hours from the time of preparation, but the necessary examinations (HIV, hepatitis, human T-cell lymphotropic virus, syphilis) may not be completed by this time. Granulocyte transfusions are rarely used, as modern antibiotics and preparations stimulating the production of granulocytes are used.
Rh-immunoglobulin (Rhlg), administered intramuscularly or intravenously, prevents the development of maternal RI antibodies that can form during fecal bleeding. The standard dose of intramuscular Rhlg (300 μg) should be given to the Rh-negative mother immediately after the abortion or childbirth (live or stillborn child), unless the child is Rh (D) and D u negative or the mother's serum already contains anti- Rh ( D). With a volume of fetomaternal bleeding of more than 30 ml, large doses of the drug are required. If a significant hemorrhage is suspected, a rosette test is performed simultaneously with the determination of the hemorrhage size, if it is positive, a quantitative test is performed (for example, Kleihauer-Bitke). Rhlg is administered only intravenously if there are contraindications to intramuscular injection (for example, in patients with coagulopathy).
Thrombose concentrate is used to prevent the development of bleeding in asymptomatic thrombocytopenia (platelet count <10 000 / μL); with bleeding with severe thrombocytopenia (platelet count <50 000 / μL); with bleeding in patients with platelet dysfunction caused by antiaggregants, with a normal level of platelets in the blood; patients receiving massive transfusions, causing dilution thrombocytopenia, and sometimes before surgery, especially with extracorporeal circulation for more than 2 hours (which often leads to platelet dysfunction). One dose of thromboconcentrate increases the platelet count by about 10,000 / μl. Adequate hemostasis is achieved with a platelet count of about 50,000 / μL. Therefore, 4-6 doses of thromboconcentrate are usually sufficient for an adult patient.
Thrombose concentrate is harvested using automatic equipment that collects platelets (or other cells), and returns unnecessary components (eg, red blood cells, plasma) to the donor. This procedure, called cytapheresis, provides a sufficient number of platelets from one donor (equivalent to 6 individual platelet doses) for transfusion to an adult patient, thereby minimizing the risk of infectious and immune complications, and is preferable to transfusions from many donors.
Some patients may not respond to platelet transfusion, possibly due to sequestration in the spleen or consumption caused by HLA alloimmunization or specific platelet antigens. Such patients can respond to transfusion of many doses of thromboconcentrate obtained from different donors (since it is possible that some doses will be HLA-compatible), on thrombocyte concentrate from relatives or ABO- or HLA-compatible platelets. Alloimmunization can be mitigated by transfusion of thrombocyte concentrate or erythrocytic mass after leukocyte depletion.
Irradiation of blood components is used to prevent the risk of "graft-versus-host disease".
The use of blood substitutes begins to develop with the use of inert chemical or hemoglobin solutions, capable of transferring and delivering O2 to tissues. Perfluorocarbons are chemically and biologically inactive and are capable of dissolving O2 and CO2 under pressure. Since perfluorocarbons are insoluble in water, they are prepared in the form of emulsions. Currently, the II and III phases of clinical trials are being conducted. Solutions based on the hemoglobin carrier of oxygen are in Phase III clinical trials in the United States. Chemically modified molecules of human or bovine hemoglobin with the ability to carry O2 are used. These solutions can be stored at room temperature for up to 2 years, which makes them necessary for use in places of disasters or military operations. However, both drugs (perfluorocarbons and hemoglobin O2 carriers) are eliminated from the plasma within 24 hours.
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