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" for transfusion therapy of critical conditions caused by hypovolemia and intoxication.

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

The albumin level under 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 body weight per day. In the vascular channel 40% of all albumin, the remaining 60% - in the interstitial and intracellular spaces. Meanwhile, it is these 40% albumin that causes 80% of the colloid-osmotic pressure of the blood plasma.

Albumin not only plays a crucial role in maintaining the colloid-osmotic pressure of the plasma, but also performs transport and detoxification functions in the body. He participates in the transport of endogenous substances such as bilirubin, hormones, amino acids, fatty acids, minerals, 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 response, promoting agglutination of antibodies on the surface of the erythrocyte membrane. Albumin is important in the regulation of CBS, since it enters the buffer system of the blood.

In a unit of time, the synthesis of albumin is occupied by one-third to one-half of all the hepatic cells. Hormones (insulin, cortisone, testosterone, adrenocorticotropic hormone, growth factors and thyroid hormone) are able to increase the rate of albumin synthesis by hepatocytes, and stress states, sepsis, fasting, hyperthermia and old age slow this process. The synthesized albumin is circulated for two minutes. The half-life of albumin is from 6 to 24 days, an average of 16 days. Since all three spaces (intravascular, interstitial and intracellular) are in the human body in dynamic equilibrium, the intravascular pool of albumin is constantly exchanged with an extravascular pool at a rate of 4.0-4.2 g / (kghsut).

The variety of functions performed by albumin in the body is the basis for using it in the treatment of various pathologies. Often there is a reassessment of the possibility of correcting the level of albumin in the bloodstream of the recipient with the help of transfusion of solutions of donor albumin of various concentrations, as well as an underestimation of the danger of albumin deficiency and the need for its correction with the help of multiple (not single!) Transfusions of its solutions.

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

• acute massive hemorrhage;
• decrease in albumin level in plasma below 25 g / l;
• the level of colloid-osmotic pressure of the plasma is below 15 mm Hg. Solutions of albumin of various concentration are produced: 5%, 10%, 20%, 25%,
• packaged in 50, 100, 200 and 500 ml. Only 5% albumin solution is isoncotic (about 20 mm Hg), all other concentrations of albumin are referred to as hyperoncotic.

Optimum in acute massive blood loss, 5% solution of albumin. If transfusion therapy of acute massive blood loss is started late or the volume of blood loss is high and there are signs of hemorrhagic hypovolemic shock, then transfusion of 20% albumin into one vein with simultaneous introduction of saline into another is shown, which has significant advantages for stabilization of hemodynamic disorders.

The need for repeated transfusions of albumin and the duration of application depend on the tasks that the doctor has set for himself, starting albumin therapy. As a rule, the goal is to maintain colloid osmotic pressure at a level of 20 mm Hg. Or an albumin concentration in the plasma of 25 ± 5 g / l, which is equivalent to a total protein concentration of 52 g / l in the blood.

The question of the expediency of using hyperoncotic solutions of albumin in various forms of shock and in those situations where there is no pronounced hypovolemia and a sharp decrease in colloid osmotic pressure has not yet been fully resolved. On the one hand, the ability of albumin to rapidly increase the colloid-osmotic pressure of the 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 to even healthy individuals increases their transcapillary leakage of albumin into the interstitial space from 5 to 15%, and when pulmonary alveoli is affected, the phenomenon is intensified. 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 rapidly "wasted" as a result of the 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 decreased colloid osmotic pressure during transfusion therapy of shock with the appointment of hyperoncotic solutions of albumin.

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

Reactions to the administration of albumin preparations are rare. Side effect of albumin is most often a consequence of allergy to foreign protein and manifests itself as hyperthermia, chills, urticaria rash or urticaria, and less often - development of hypotension. The latter is due to the presence in the albumin of the prekallikrein activator, the hypotensive effect of which is noticeable when the solution is administered too rapidly. Adverse reactions are early - within two hours from the beginning of the transfusion (more often when using 20-25% albumin solution) and later - after 1-3 days after.

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

Violation of the technique of transfusion can also be caused by the appearance of circulatory overload. The higher the concentration of the administered albumin solution, the slower the rate of its administration and the more careful control of the condition of the recipient. The risk of developing adverse reactions also increases with increasing concentration of the administered solution, especially if the patient has an immunocomplex pathology or an allergic predisposition.

Circulatory congestion usually develops during or immediately after the transfusion, it is characterized by shortness of breath, tachycardia, increased blood pressure, acrocyanosis and the possible development of pulmonary edema. Therapy involves the termination of transfusion, the appointment of diuretics (intravenously), intranasally or through a mask - oxygen, giving the patient an elevated position of the head end. Sometimes resort to bloodletting in a volume of up to 250 ml. In the absence of the effect, the patient is transferred to the intensive care unit.

Allergic manifestations are treated with antihistamine drugs intramuscularly or intravenously. With anaphylactic transfusion reactions on albumin, discontinuation of transfusion, oxygen supply and intravenous saline injection with parallel administration of epinephrine with 0.3-0.5 ml of a 1: 1000 solution must be performed subcutaneously. Epinephrine can be repeated twice more at intervals of 20-30 minutes. When bronchospasm appears - euphyllin, atropine, prednisolone. With ineffective therapy - urgent transfer to the intensive care unit.

[1], [2], [3], [4], [5], [6], [7], [8], [9], [10]