Albumin: albumin transfusion

The most important plasma protein is albumin, solutions of which are widely used in surgical practice. Experience shows that the use of albumin solutions is the "gold standard" of transfusion therapy for critical conditions caused by hypovolemia and intoxication.

Albumin is a protein with a relatively small molecule, the molecular weight of which is in the range of 66,000-69,000 daltons. It easily enters into compounds with both anions and cations, which determines its high hydrophilicity. Calculations have shown that each gram of albumin attracts 18-19 ml of water from the interstitial to the intravascular space. In practice, due to the "capillary leakage" of transfused albumin, such results are usually not obtained.

The albumin level in normal conditions in an adult is 35-50 g/l, which is 65% of the total protein. It is selectively synthesized in the liver at a rate of 0.2 g/kg of body weight per day. In the vascular bed, 40% of all albumin, the remaining 60% - in the interstitial and intracellular spaces. Meanwhile, it is these 40% of albumin that determine 80% of the colloid-osmotic pressure of blood plasma.

Albumin not only plays a vital role in maintaining the colloid-osmotic pressure of plasma, but also performs transport and detoxification functions in the body. It participates in the transport of such endogenous substances as bilirubin, hormones, amino acids, fatty acids, minerals, and binds exogenous toxic substances entering the body. Due to the presence of a thiol group, albumin is able to bind and remove free radicals from the bloodstream. In addition, it accelerates the antigen-antibody reaction, promoting the agglutination of antibodies on the surface of the erythrocyte membrane. Albumin is of great importance in the regulation of acid-osmotic balance, since it is part of the blood buffer system.

From one third to one half of all liver cells are involved in albumin synthesis per unit of time. Hormones (insulin, cortisone, testosterone, adrenocorticotropic hormone, growth factors and thyroid hormone) are able to increase the rate of albumin synthesis by hepatocytes, and stress conditions, sepsis, starvation, hyperthermia and old age slow down this process. Synthesized albumin enters the circulation within two minutes. The half-life of albumin is from 6 to 24 days, on average 16 days. Since all three spaces (intravascular, interstitial and intracellular) are in dynamic equilibrium in the human body, the intravascular pool of albumin constantly, at a rate of 4.0-4.2 g / (kg x day) exchanges with the extravascular pool.

The diversity of functions performed by albumin in the body serves as the basis for its use in the treatment of various pathologies. Often there is an overestimation of the possibilities of correcting the level of albumin in the recipient's bloodstream by transfusing solutions of donor albumin of various concentrations, as well as an underestimation of the danger of albumin deficiency and the need to correct it by multiple (not single!) transfusions of its solutions.

The main indications for the use of albumin in surgical practice:

• acute massive blood loss;
• decrease in plasma albumin levels below 25 g/l;
• the level of colloid osmotic pressure of plasma is below 15 mm Hg. Albumin solutions of various concentrations are produced: 5%, 10%, 20%, 25%,
• packaged in 50, 100, 200 and 500 ml. Only 5% albumin solution is isooncotic (about 20 mm Hg), all other albumin concentrations are considered hyperoncotic.

The optimal solution for acute massive blood loss is a 5% albumin solution. However, if transfusion therapy for acute massive blood loss is started late or the volume of blood loss is large and there are signs of hemorrhagic hypovolemic shock, then transfusion of 20% albumin into one vein with simultaneous administration of saline into another is indicated, which has significant advantages for stabilizing hemodynamic disorders.

The need for repeated albumin transfusions and the duration of use depend on the goals set by the physician when initiating albumin therapy. As a rule, the goal is to maintain colloid osmotic pressure at 20 mm Hg or plasma albumin concentration of 25±5 g/l, which is equivalent to a total blood protein concentration of 52 g/l.

The question of the advisability of using hyperoncotic albumin solutions in various forms of shock and in situations where there is no pronounced hypovolemia and a sharp decrease in colloid-osmotic pressure has not yet been finally resolved. On the one hand, the ability of albumin to quickly increase the colloid-osmotic pressure of plasma and reduce the amount of fluid in the pulmonary interstitial space can play a positive role in the prevention and treatment of "shock lung" or adult respiratory distress syndrome. On the other hand, the introduction of hyperoncotic albumin solutions even to healthy individuals increases their transcapillary leakage of albumin into the interstitial space from 5 to 15%, and in case of damage to the pulmonary alveoli, an increase in this phenomenon is observed. At the same time, a decrease in the removal of protein from the pulmonary parenchyma with lymph is observed. Consequently, the "oncotic effect" of transfused albumin is quickly "wasted" as a result of redistribution and accumulation of albumin in the interstitial space, which can lead to the development of interstitial pulmonary edema. Therefore, one should be very careful in conditions of normal or slightly reduced colloid osmotic pressure during transfusion therapy of shock with the administration of hyperoncotic albumin solutions.

Administration of albumin solutions is contraindicated in patients with arterial hypertension, severe heart failure, pulmonary edema, and cerebral hemorrhage due to the possible increase in the severity of these pathological conditions due to an increase in the volume of circulating plasma. A history of hypersensitivity to protein preparations also requires refusal to prescribe albumin preparations.

Reactions to the introduction of albumin preparations are rare. Side effects of albumin are most often a consequence of an allergy to a foreign protein and are manifested by hyperthermia, chills, urticarial rash or urticaria, less often - the development of hypotension. The latter is due to the presence of prekallikrein activator in albumin, the hypotensive effect of which is noticeable when the solution is administered too quickly. Side effects are early - within two hours from the start of the transfusion (more often when using a 20-25% albumin solution) and late - 1-3 days later.

Domestic albumin solutions should be stored in the refrigerator at a temperature of 4-6 ° C. Foreign albumin preparations do not require this. All albumin solutions are transfused only intravenously. If it is necessary to dilute the drug, 0.9% sodium chloride solution or aqueous 5% glucose solution can be used as diluents. Albumin solutions are administered separately; they should not be mixed with protein hydrolysates or amino acid solutions. Albumin preparations are compatible with blood components, standard saline solutions, and carbohydrate solutions. Typically, the transfusion rate of albumin solutions in adult patients is 2 ml/min. In case of severe hypovolemia (the cause of shock), the volume, concentration, and rate of transfused albumin must be adapted to the specific situation. These parameters largely depend on the response to transfusion therapy.

Violation of transfusion technique may also cause circulatory overload. The higher the concentration of the administered albumin solution, the slower the rate of its administration and the more careful monitoring of the recipient's condition should be. The risk of developing adverse reactions also increases with the concentration of the administered solution, especially if the patient has immune complex pathology or allergic predisposition.

Circulatory overload usually develops during or immediately after transfusion, characterized by dyspnea, tachycardia, increased blood pressure, acrocyanosis and possible development of pulmonary edema. Therapy involves stopping the transfusion, administering diuretics (intravenously), intranasally or through a mask - oxygen, giving the patient an elevated position of the head end. Sometimes they resort to bloodletting in a volume of up to 250 ml. If there is no effect, the patient is transferred to the intensive care unit.

Allergic manifestations are treated with antihistamines intramuscularly or intravenously. In case of anaphylactic transfusion reactions to albumin, it is necessary to stop the transfusion, administer oxygen and intravenously administer a saline solution with parallel administration of epinephrine 0.3-0.5 ml of a 1:1000 solution subcutaneously. Epinephrine can be administered again twice more at intervals of 20-30 minutes. If bronchospasm occurs - euphyllin, atropine, prednisolone. If therapy is ineffective - urgent transfer to the intensive care unit.

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ], [ 8 ], [ 9 ]