Detoxification hemosorption

Therapeutic hemosorption is based on the fixation of chemical compounds on nonselective carbon sorbents of natural or synthetic origin, which is determined by the forces of molecular coupling of van der Waals, the strength of which is due to the formation of covalent bonds between the toxicant and the sorbent. Effective sorption of target metabolites is ensured by a large total surface area of the sorbent - up to 1000 m ² / g, where the surface area of the coal formed by the pores is much larger than the outer surface area of the coal, and the total pore volume is up to 1 ml / g. The degree of sorption mainly depends on the capacity of the micropores of the sorbent, as well as on the polarizability and geometric characteristics of the sorbed toxic substance.

In general, the sorption capacity of activated carbon is very high 1 g of activated charcoal can sorb from inorganic solutions 1.8 g of mercuric chloride, 1 g of sulfonamides, 0.95 g of strychnine, 0.9 g of morphine, 0.7 g of atropine, 0.7 g barbitol, 0.3-0.35 g of phenobarbital, 0.55 g of salicylic acid, 0.4 g of phenol and 0.3 g of ethanol.

The sorption kinetics in the outer layer of the sorbent determines the sorbate intake and limits the molecular diffusion of the sorbed component in an unmixable thin layer immediately adjacent to the surface of the granules, called the Nernstov film, which breaks down only when the flow of the biological fluid is strongly turbulized. The sorption rate in this case is inversely proportional to the effective radius of the granules, and the activation energy of external diffusion is relatively low and amounts to only 4-20 kJ / mol. The speed of the process increases with the turbulization of the flow, which reduces the thickness of the Nernst film, and also with an increase in the concentration of the sorbed component.

Intradiffusion kinetics, in turn, determines the concentration of the sorbent in the micropores and its diffusion gradient. The rate of sorption in this case is inversely proportional to the radius in the square of the sorbent granules. The activation energy of diffusion under this type of kinetics is much higher and amounts to 40-120 kJ / mol. Thus, with intradiffusion kinetics, it is desirable to use sorbents with the smallest possible granule size, which makes it possible to substantially intensify the process. In micropores, the most fixed fixation of toxic substances and the fastest kinetics are noted. In addition, due to the high adsorption potential in the region of micropores, larger molecules can also be fixed.

A large number of natural (mineral, animal, plant) and synthetic sorbents have been synthesized, and the activity of vegetable sorbents is recognized as higher than that of others.

In the mechanism of the therapeutic action of hemosorption, three main components are identified: ethiospecific, associated with the accelerated removal of the etiologic factor, i.e., a toxicant that caused poisoning, pathospecific, detectable by eliminating pathogenetically significant factors ("medium molecules", circulating immune complexes, etc.), nonspecific , manifested in the correction of indices of homeostasis. The main advantage of hemosorption is the intensive extraction from the blood of hydrophobic and fat-soluble toxic substances (clearance 70-150 ml / min), which allows for a short time to reduce the concentration of the toxicant in the blood from deadly or critical to threshold and thereby minimize the space-time lag of therapeutic measures in relation to the moment of poisoning. The immediate detoxification effect of hemosorption is supplemented by the purification of blood from "medium molecules", the clearance of which reaches 25-30 ml / min.

Among the non-specific effects of hemosorption, its effect on hemorheological indices is most noticeable, primarily due to the disaggregation of the formed elements (erythrocytes, platelets). The blood viscosity, hematocrit decreases, the fibrinolytic activity of the blood plasma increases, which leads to the removal of fibrin degradation products from the microcirculatory bed, resulting in a significant decrease in the degree of development of the DIC syndrome and associated organ disturbances. On the 1-3th day after hemosorption, the content of the most fully functional, highly resistant red blood cells in the blood increases noticeably and the number of low-resistant cells decreases.

The favorable effect of hemosorption on homeostasis is accompanied by a significant acceleration of the removal of toxic substances from the body, which is manifested by a 3-10-fold decrease in the half-life of toxicants in the blood (barbiturates, FOI, chlorinated hydrocarbons), and tissue resistance to toxicants in high concentrations . The high clinical and laboratory efficacy of hemosorption is noted in cases of poisoning with psychotropic and hypnotics (barbiturates, benzodiazepines, phenothiazines, leponex, etc.), FOI, salicylates, quinine, pachycarpine hydroiodide, antituberculosis drugs and many other toxicants, hemosorption is most effective at early poisonings poisonous mushrooms (pale toadstool, false mushrooms, etc.).

The clinical effect of hemosorption in toxicogenic stage of poisoning is manifested by reduction of the duration of toxic coma, correction of endotoxicosis laboratory parameters, which contributes to more favorable flow or prevention of organ disorders, especially liver-renal and neurological. As a result, the duration of inpatient treatment of patients decreases.

[1], [2], [3], [4], [5], [6]

The method of detoxification hemosorption in acute poisoning

Equipment	Apparatus for hemosorption Perfusion blocks apparatus for HD, plasmapheresis, hand pump With short-term (within 30-40 minutes) arteriovenous perfusion, the perfusion block is not needed
Mass-exchange device	When performing hemosorption in the prehospital stage, the amount of sorbent can be reduced to 75-100 ml with a corresponding decrease in the mass exchanger sizes
System of highways	Disposable special When using vials with a sorbent - additionally a universal slotted nozzle for ensuring blood flow through the sorbent
Vascular access	Catheterization of the main vein, when using a subclavian vein - followed by chest radiography, an arteriovenous shunt
Preliminary preparation
Hemodilution	12-15 ml of liquid per 1 kg of body weight of the patient before the reduction of hematite tokrit in the range of 35-40% and the achievement of CVP of the order of 60-120 mm of water
Autocovering of the surface of bent blood with blood	When using natural (uncovered) coals, perfusion through a sorbent of a special protective solution (5 ml of patient's blood + 400 ml of 0.85% sodium chloride solution) with the addition of sodium heparin (5000 units) for 10-15 min. In unstable hemodynamics, 50 mg of prednisolone and 1-2 ml of a 0.1% solution of noradrenaline (or epinephrine and ephedrine)
Heparinization	Total, 350-500 units of sodium heparin per 1 kg of body weight of the patient. At the risk of bleeding - dosed heparinization with a decrease in the dose of sodium heparin by a factor of 1-5-2 with its constant intravenous drip in isotonic solutions of glucose or electrolytes, or regional heparinization with inactivation of sodium heparin protamine sulfate at the outlet from the sorption column
Method of perfusion of blood	The blood is taken from the vessel by means of a pump, it enters the detoxifier column, contacts the sorbent and returns to the blood take from the vessel by means of a pump, it enters the vial containing activated charcoal, along the inner channel of the universal perfusion slot nozzle, contacts the sorbent and the external channel slit nozzle is returned to the bloodstream through the second vessel drift blood (with arteriovenous shunt) into the column with a sorbent or a vial - in the presence of hemodynamic instability at risk worsening its disorders venoarterialnaya perfusion of blood by the pump during the development of hemodynamic disorders - within 30-40 min in order to avoid growth acidotic changes in arterial blood
Blood perfusion rate	During the first 5-10 minutes of operation - a gradual increase in the perfusion rate of blood from 50-70 ml / min to 100-150 ml / min with maintaining the reached rate of blood flow to the end of the operation
Blood perfusion volume	1-1.5 BCC (6-9 L) during one session of hemosorption (1 h)
Recommended Modes	The duration of one session of hemosorption -1h When using columns of 150 ml, the duration of each of the columns is 30 min. The number of sessions of hemosorption is no more than 3. In the intervals between sessions, an intensive diuresis, measures for correcting the water-electrolyte and acid-base balance and other parameters homeostasis
Indications for use	Clinical poisoning with plodoaginizing poisons, a pronounced clinical picture of poisons poisoned for a long time circulating in the blood. Laboratory presence of deadly concentrations of poisons in the blood and critical concentrations of poorly dialyzing poisons
Contraindications	Refractory to hypotension. Gastrointestinal and cavitary bleeding
Premedication	Chloropyramine (1-2 ml of a 1% solution), prednisolone (30-60 mg) intravenously