With blood loss, there is a need to urgently transfuse blood. Using a natural substance is not always possible. This is due to the fact that doctors do not have the right amount of time to carry out all the necessary tests for the compatibility of the blood of the donor and recipient. As a result, the latter may have a complication, up to a blood transfusion shock, which is life-threatening. To avoid this, blood substitutes are used in clinics. The classification of these substances allows you to choose exactly the type that is suitable in a particular case.
But what is it? Blood substitutes are drugs that replace blood and plasma. These fluids are used for therapeutic purposes to replace blood with varying degrees of blood loss in order to quickly restore the volume of circulating blood. Different species have different properties, for example, there are drugs that can deliver oxygen to tissues, some have an osmotic effect, but they all restore the volume of circulating blood in the vascular bed.
General properties
Regardless of the concept of blood substitutes, their classification, they should all have certain properties. By their biological and physicochemical properties, they should be close to the blood plasma.
Blood substitutes should have the following properties:
- isoionic properties - to have an ionic composition close to the composition of the plasma;
- isotonic properties - pressure should be equal to blood plasma (7.7 atm);
- isosmolar;
- pyrogen-free properties;
- immunonert;
- must withstand certain sterilization conditions;
- should be stored for a long time under normal conditions.
In addition, all blood substitutes must have a certain set of properties, for example, the ability to deliver oxygen to body tissues.
Drug requirements
Regardless of the classification, blood substitutes have the following requirements:
- they should not be toxic;
- should not cumulate;
- should be easy to use;
- should not cause an allergic reaction.
Despite the variety of fluids, none of them can fully simulate the function of blood. But they can effectively perform one function or several. In the first case, the substance is classified as single-functional, and in the second - to multi-functional. If the drug has a number of functions, then it is classified as multifunctional.
Varieties by Group
The modern classification of blood substitutes divides all substances into six large groups. The first includes hemodynamic drugs or anti-shock. The second group includes detoxification drugs, and the third - preparations for parenteral nutrition.
There are substances intended for the correction of water-electrolyte metabolism and acid-base balance, oxygen carriers and blood substitutes with a complex effect.
Chemical division
The classification of blood substitutes by infusion solutions divides the preparations according to their chemical properties into the following types:
- electrolyte;
- fatty;
- alcohol;
- carbohydrate;
- protein
- alcohol.
Complex drugs are also isolated.
Six groups
The most correct method for classifying blood products and blood substitutes by the mechanism of action. According to this principle, all substances are divided into six large groups, each of which has its own subgroups.
The first group is antishock fluids. It includes drugs based on dextran, which are low, medium molecular weight. These are substances such as Polyglukin, Plazmodex, Lomodex, Hemodex. It also includes gelatin preparations - Gelatinol, Gelofusin, and others.
The second group is a liquid of non-toxic properties used in the treatment of intoxication pathological conditions. This group includes drugs developed on the basis of low molecular weight polyvinylpyrrolidone and polyvinyl alcohol. These are "Hemodez", "Neocompensation", "Polydez" and others.
The third group - drugs intended for parenteral protein nutrition. These are mixtures of amino acids and protein hydrolysates. The third group includes drugs: Casein Hydrolyzate, Aminon, Polyamine, Aminopeptide.
The fourth group - regulators of acid-base composition and water-salt metabolism. These include saline solutions such as Lactasol, Acesol, Trisol, Ringer Lactate.
Liquids capable of carrying oxygen. Drugs belonging to this group are under development. This includes:
- hemoglobin solutions - purified impurities of concentrated hemoglobins, which provided life to bloodless animals for several days;
- fluorocarbon emulsions - the model is designed so that the substance can deliver oxygen to the tissues.
According to the classification of blood substitutes, group 6 are substances with a complex effect. This group has three subgroups. The first includes solutions of hemodynamic and detoxification effects, developed on the basis of polyglucin, reopoliglukin and lactasol. Final preparations have enhanced anti-shock property.
On the basis of polyglucin, scientists have obtained a substance - a polyfer that enhances erythropoiesis. Rheogluman, a substance with a diuretic, rheological effect, was also obtained.
Application
Depending on the classification of blood substitutes, indications for the use of different fluids are different. The drug "Polyglukin", related to medium molecular anti - shock drugs, is able to circulate in the bloodstream for up to four days, gradually leaving it. After administration, the drug begins to actively draw tissue fluid into the bed, thereby increasing blood pressure.
Indications for the use of liquids are:
- The shock is traumatic.
- Acute blood loss.
- Shock burn.
- The shock is operational.
- Circulatory failure arising from various pathologies.
There are no contraindications to the use of the drug, except when it is impossible to prevent a sharp jump in blood pressure, due to which bleeding can continue.
Other drugs
The mechanism of the therapeutic effect of the blood substitute, the classification of low molecular weight polyvinylpyrrolidones, is associated with the elimination of toxins from the body, improved microcirculation, as well as the elimination of red blood cell stasis. These properties have the drug "Hemodez." It is prescribed for foodborne diseases, burn disease, dyspepsia, dysentery, anuria, sepsis, nephropathy of pregnant women. "Hemodez" is indicated for intestinal paresis, vomiting. He has no contraindications. The substance is released in a bottle with a volume of 400 ml.
Among protein hydrolysis, the most commonly used is “Casein Hydrolyzate”, obtained by hydrolysis of casein washed from sulfuric and lactic acid. The drug is a mixture of the simplest peptides and amino acids. It is devoid of toxicity, well absorbed by the body.
Protein hydrolysates are administered intraosseously, intramuscularly, subcutaneously and intradermally, but it is most preferable to use them intravenously. Indications for the use of hydrolysates are the depletion of the body in the postoperative period, burn disease, purulent-septic pathologies. They are indicated for use in malignant neoplasms, gastrointestinal pathologies.
Conclusion
To replenish the blood volume, isotonic sodium chloride solution, ring solutions, “Lactasol” are used. These drugs are indicated for dehydration, intoxication, hypovole. To combat the shock state, acidosis, electrolyte cocktails are made. They may contain Acesol and Chlosol, or Trisol and Disol. Similar mixtures are sold ready-made. In some cases, doctors mix the drugs on their own to get the right shake. They can be harvested in large quantities and stored, transported for a long period.
Blood substitutes can be used in a hospital, in the field, in an ambulance. This is due to the fact that the drugs can be stored for a long time under ordinary conditions.