Erythrocyte mass

Red blood cell mass (RBC) is a blood component consisting of red blood cells (70-80%) and plasma (20-30%) with an admixture of white blood cells and platelets (hematocrit - 65-80%). In terms of red blood cell content, one dose of red blood cell mass (270 ± 20 ml) is equivalent to one dose (510 ml) of blood.

There are 6 types of red blood cell mass (filtered red blood cell mass; gamma-irradiated red blood cell mass; red blood cell mass depleted of leukocytes and platelets; red blood cell mass with buffy coat removed; filtered red blood cell mass with buffy coat removed; gamma-irradiated red blood cell mass with buffy coat removed) and several types of auto red blood cell mass (auto-EM; filtered autoEM; gamma-irradiated autoEM, etc.).

Erythrocyte suspension (ES) is an erythrocyte mass resuspended in a special solution of sodium chloride and a hemopreservative containing gelatin preparations and some other components. As a rule, the ratio of erythrocyte suspension and solution is 1: 1. Erythrocyte suspension, acquiring higher fluidity and, accordingly, higher rheological properties, simultaneously has a lower hematocrit number (40-50%).

There are 5 types of erythrocyte suspension (erythrocyte suspension with physiological solution, erythrocyte suspension with resuspending solution, erythrocyte suspension with resuspending solution, filtered, erythrocyte suspension with resuspending solution, gamma-irradiated, erythrocyte suspension, defrosted and washed).

Leukocyte- and platelet-depleted red blood cell mass (washed red blood cells - (WRBC) is a red blood cell mass deprived of plasma, as well as leukocytes and platelets, by 1-5-fold repeated addition of physiological solution and removal of the supernatant after centrifugation. Washed red blood cell mass is stored until use in a suspension of 100-150 ml of physiological solution with a hematocrit of 0.7-0.8 (70-80%).

To remove leukocytes from whole preserved blood or red blood cell mass, special filters are actively used, which allow the removal of more than 99% of leukocytes, which allows a sharp reduction in the number of post-transfusion reactions of the non-hemolytic type and thereby increase the effect of treatment procedures.

Erythrocyte suspension, defrosted and washed - a method of freezing and storing erythrocytes at low temperatures (up to 10 years) allows to obtain functionally complete erythrocytes after defrosting and washing from cryoprotector (glycerol). In a frozen state, erythrocytes can be up to 10 years.

Just as with donor blood, it is more expedient from both a medical and economic point of view to procure its components instead of whole preserved autoblood - autologous (autogenous) hemocomponents: red blood cell mass, fresh frozen plasma (FFP), and in some cases, thromboconcentrate. With adequate drug preparation of the patient (iron preparations, vitamin therapy, erythropoietin), 2-3 weeks before the operation, it is possible to procure from 600-700 to 1500-18,000 ml of autoFFP, 400-500 ml of autoEM.

In some cases, autoEV with a physiological solution is obtained from autoEM, or with additional filtration - autoEV with a resuspending solution, filtered.

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Red blood cell mass: place in therapy

Red blood cell mass is prescribed to relieve anemia and enhance the oxygenating function of the blood. Unlike canned blood, the use of EM significantly reduces the likelihood of immunization of the patient with plasma proteins, leukocytes and platelets of donor blood.

In patients with normal initial hemoglobin, hematocrit, and plasma protein values with blood loss within 10-15% of the BCC, there is no need to use EM. It is sufficient to maintain stable hemodynamics and compensate for blood loss with blood substitutes.

With blood loss of more than 15-20% of the BCC, as a rule, the first signs of a violation of the oxygen transport function of the blood are observed, which requires adequate replenishment of the red blood cell deficiency, i.e. the use of EM. Transfusions of EM, EV can be performed by drip or jet.

It is impossible and hardly advisable to establish any absolute laboratory criteria for the appointment of EM. First of all, it is necessary to take into account the clinical condition of the patient, concomitant pathology, the degree and location of the injury, the cause of anemia, bleeding time and many other factors. Thus, it is known that patients with chronic anemia are more adapted to a low hemoglobin level. At the same time, patients with arterial hypotension, with severe cardiopulmonary insufficiency, with infectious diseases, etc. require EM transfusions even with higher values of red blood indices.

In chronic blood loss or in case of hematopoiesis failure, the basis for red blood cell transfusion in most cases is a drop in the blood hemoglobin level below 80 g/l and hematocrit below 25% (0.25 l/l). To improve the rheological properties of EM (or EC), 50-100 ml of 0.9% sodium chloride solution can be added to the container immediately before transfusion, which effectively turns it into EV with physiological solution. Indications for transfusion of EV, OE, defrosted OE are similar to the prescriptions for red blood cell mass:

• traumatic and surgical shock complicated by blood loss;
• anemic hypoxia in normo-hypovolemic conditions;
• posthemorrhagic anemia;
• during the period of preparation of patients with critically low hemogram indicators for extensive surgical interventions;
• post-thermal (in burn disease) anemia.

Washed red blood cell mass is used in patients sensitized by previous blood transfusions to plasma factors or leukocyte and platelet antigens. The cause of most transfusion reactions of the non-hemolytic type in patients with a history of multiple transfusions of blood components, as well as in women who have had pregnancies, are isoantibodies to leukocyte antigens (in particular, HLA), which undoubtedly reduce the effect of not only the transfused component, but also the entire treatment procedure. Washing of red blood cell mass almost completely eliminates plasma and elements of destroyed peripheral blood cells, platelets and sharply reduces the leukocyte content (< 5 x 109).

Indications for the use of washed erythrocytes:

• anemias of various etiologies, accompanied by sensitization of the recipient to antigens of plasma proteins, leukocytes and platelets as a result of repeated blood transfusions or pregnancy;
• homologous blood syndrome (as an element of complex therapy);
• compensation for blood loss in allergic patients (bronchial asthma, etc.) in order to prevent anaphylactic reactions.

AutoEM transfusions in the intra- and postoperative period for the purpose of correcting anemia are performed if indicated.

For immunocompromised patients, gamma-irradiated autoEM or gamma-irradiated autoEV with resuspension solution is recommended.

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Physiological properties of red blood cell mass

Autoblood components are parts of the patient's own blood, which determines their physiological properties - providing tissues and cells of the body with oxygen and delivering carbon dioxide to the lungs. After 8-10 days of storage, minor hemolysis may be detected in the red blood cell mass, which is not a contraindication for its clinical use. The longer the storage period, the lower the oxygen-transport function of the red blood cells. Red blood cell components contain less preservative than whole blood, and it is completely absent in the OE. Washed red blood cell mass contains trace amounts of plasma protein components, platelets, and leukocytes.

Pharmacokinetics

Components containing donor erythrocytes function in the body after blood transfusion for several days to several weeks, which is largely determined by the time of preparation of erythrocytes, the type of preservative and the conditions of their storage (native, defrosted, washed). In the body, destroyed donor erythrocytes are utilized by cells of the reticuloendothelial system of parenchymatous organs.

Contraindications

Contraindications to the use of EM and EV: massive blood loss (more than 40% of the circulating blood volume), hypocoagulation states, thromboembolism of various origins, acquired non-hemolytic anemia.

Hemolysis of autoblood or autoEM (EV) (free hemoglobin > 200 mg%) is a contraindication for blood transfusion. Such red blood cell mass is washed before blood transfusion.

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Tolerability and side effects

If the rules for procurement, processing, storage and use of donor erythrocytes are followed and are adequate to the patient’s clinical condition, the risk of reactions and complications is reduced to a minimum.

Warming of blood components reduces the risk of hypothermia during massive transfusions of cooled blood components. The minimum recommended temperature of transfused blood and its components is +35° C. During transfusion of unwarmed blood or its components, ventricular arrhythmias can sometimes be observed (usually do not develop until body temperature drops below +28° C).

There are pyrogenic, allergic, anaphylactic, and febrile (non-hemolytic) types of blood transfusion reactions.

Post-transfusion reactions, as a rule, are not accompanied by serious and long-term dysfunction of organs and systems and do not pose an immediate danger to the patient's life. They manifest, as a rule, 10-25 minutes after the start of blood transfusion, in some cases they are noted after the end of blood transfusion and, depending on the severity, can last from several minutes to several hours.

Pyrogenic reactions (hyperthermia) occur as a result of the infusion of pyrogens into the recipient's bloodstream along with preserved blood or its components. Pyrogens are nonspecific proteins, products of the vital activity of microorganisms. Post-transfusion pyrogenic reactions may also occur in patients isosensitized by repeated blood transfusions or in women with a history of multiple pregnancies in the presence of antileukocyte, antiplatelet or antiprotein antibodies. Filtration of blood through leukofilters and washing allows to sharply reduce the risk of isosensitization of patients with multiple blood transfusions.

When pyrogenic reactions occur, chills appear, the temperature rises to +39 or 40° C, usually 1-2 hours after the blood transfusion, less often during it. Fever is accompanied by headache, myalgia, chest discomfort, pain in the lumbar region. The clinical picture may have varying degrees of severity. Blood transfusions often occur with subfebrile temperature, which usually passes quickly. The prognosis for pyrogenic reactions is favorable. Clinical signs disappear after a few hours.

Allergic reactions of varying severity are observed in 3-5% of cases of blood transfusion. As a rule, they are registered in patients sensitized by previous blood transfusions or who have had a history of repeated pregnancies with antibodies to antigens of plasma proteins, leukocytes, platelets and even Ig. In some patients, allergic reactions are observed already at the first transfusion of blood components and are not associated with previous isosensitization. It is believed that in such cases these reactions are caused by the presence of "spontaneous" antibodies to Ig and the IgE response of the recipient's mast cells to the transfused specific antigen of the donor, which is often associated with platelets or plasma proteins.

Allergic reactions may occur both during the transfusion of blood or its components, and later, 1-2 hours after the procedure. A characteristic sign of an allergic post-transfusion reaction is an allergic rash, often accompanied by itching. In a more severe reaction - chills, headaches, fever, joint pain, diarrhea. It should be borne in mind that an allergic reaction can occur with symptoms of an anaphylactic nature - respiratory failure, cyanosis, sometimes - with the rapid development of pulmonary edema. One of the most formidable complications of blood transfusion is an anaphylactic reaction, sometimes rapidly developing into anaphylactic shock.

According to the severity of the clinical course (body temperature and duration of manifestation), three degrees of post-transfusion reactions are distinguished: mild, moderate, severe.

Mild reactions are characterized by a slight increase in temperature, headache, slight chills and malaise, pain in the muscles of the extremities. These phenomena are usually short-lived - 20-30 minutes. Usually, no special treatment is required to stop them.

Moderate reactions - increased heart rate and respiration, temperature increase by 1.5-2° C, increasing chills, sometimes urticaria. In most cases, drug therapy is not required.

Severe reactions - cyanosis of the lips, vomiting, severe headache, pain in the lower back and bones, shortness of breath, urticaria or edema (Quincke type), body temperature rises by more than 2° C, severe chills, leukocytosis are observed. It is necessary to start drug correction of hemotransfusion complication as soon as possible.

Since autocomponents are immunoidentical to the patients' blood, reactions and complications associated with the transfusion of donor blood components are absent, provided that all rules of blood transfusion are observed.

Interaction

It is not recommended to use glucose solutions (5% glucose solution or its analogues cause aggregation and hemolysis of erythrocytes) and solutions containing calcium ions (cause blood clotting and clot formation) for the preparation of EV.

The red blood cell mass is diluted with physiological solution. The use of EM solution in a low-molecular dextran solution in a ratio of 1:1 or 1:0.5 reliably preserves the BCC, reduces aggregation and sequestration of formed elements during the operation and the following day.

Red blood cell mass in a solution of 8% gelatin with sodium citrate, chloride and bicarbonate is essentially an original blood component - red blood cell transfusate, which not only replenishes blood loss and restores the oxygen-transport function of the blood, but also has a hemodynamic disaggregating effect with a fairly pronounced volemic effect. The use of 8% gelatin with sodium citrate, chloride and bicarbonate as a preservative allows extending the shelf life of the OE to 72 hours.

Cautions

Erythrocyte mass is stored for 24-72 hours (depending on the preservative solution) at a temperature of +4° C. Ready-to-use EV, defrosted and washed, should have a hematocrit within 0.7-0.8 (70-80%). The shelf life of washed EM before use due to the risk of bacterial contamination may not exceed 24 hours at +1-6° C.

Administration of excessive amounts of EM or EV may result in hemoconcentration, which reduces CO and thereby worsens hemodynamics in general.

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