Intensive Care of Acute Poisoning - A. V. Hovenko 2010

Methods of detoxification therapy
Methods of artificial detoxification

The application of artificial detoxification Methods helps enhance natural detoxification processes. This phenomenon is associated with the presence of so-called nonspecific effects of artificial detoxification.

Most methods of artificial detoxification are based on the principles of dilution, dialysis, filtration, and sorption.

Artificial detoxification includes methods of intra- and extracorporeal detoxification, hemodilution, exchange Blood transfusion, plasmapheresis, lymphorrhea, hemodialysis, peritoneal and intestinal dialysis, hemoperfusion, hemofiltration, entero-, Lymph-, and plasmasorption, plasma- and lymphodialysis, and quantum hemotherapy (ultraviolet and laser blood irradiation).

Some of these methods are widely used in modern clinical toxicology (hemoperfusion, hemodialysis, hemofiltration, enterosorption, plasmasorption). Other methods (exchange blood transfusion, peritoneal dialysis) have currently lost their relevance due to relatively low efficacy. The primary task of a physician in treating Acute Poisoning is to select the optimal combination of various artificial detoxification methods and symptomatic therapy, applying them sequentially and comprehensively, taking into account each specific clinical situation.

Plasmapheresis is the Separation of blood into formed elements and plasma, with the return of the formed elements into the bloodstream and the removal of the plasma.

This method is indicated for acute hepatorenal failure caused by organotropic poisons; in the somatogenic stage; and when Other Methods of artificial detoxification are unavailable. Its efficacy in the toxicogenic stage corresponds to that of an exchange blood transfusion and is achieved when replacing a plasma volume of at least 1-1.5 BV (blood volumes). Unlike an exchange blood transfusion, plasmapheresis avoids immune conflicts and hemodynamic complications.

Methodology. A vein is catheterized, followed by the exfusion of 300-500 ml of blood into a plastic bag. The obtained blood is centrifuged for 5 minutes at 2000 rpm, which allows it to be separated into plasma and formed elements. The plasma is removed or passed through a sorbent, while the formed elements are returned to the patient's body. During the plasmapheresis Procedure, 1 to 2 liters of plasma containing dissolved toxins are removed from the patient's vascular bed. As plasma-substituting solutions, a 5-10% albumin solution, native or dry plasma, and saline solutions are used.

Hemodialysis is a method of extracorporeal blood purification through filtration of Nitrogen METABOLISM products, toxic substances, as well as excess fluid and electrolytes across a semipermeable membrane. Early hemodialysis (within the first 5-6 hours) is indicated in the toxicogenic stage of poisoning with OPUs, dichloroethane, methyl alcohol, Ethylene glycol, heavy metal compounds, arsenic, barbiturates, and carbon tetrachloride.

Blood ultrafiltration is the removal of Water, electrolytes, and low-molecular-weight compounds from the blood via convective transport across a semipermeable membrane driven by a hydrostatic pressure gradient on both sides.

Blood ultrafiltration, along with hemodialysis and hemoperfusion, is a method of extracorporeal body detoxification.

The driving force of blood ultrafiltration is the transmembrane pressure, which is the algebraic sum of the pressures at the inlet and outlet of the ultrafilter and the pressure in its internal cavity (between the membrane and the housing). The maximum transmembrane pressure should not exceed 5000 mm Hg. Higher pressure does not increase ultrafiltration performance; on the contrary, it may cause hemolysis or rupture of the dialyzer membrane.

Blood ultrafiltration is indicated for poisonings caused by water-soluble low-molecular-weight toxins.

Methodology. To perform blood ultrafiltration, veno-venous, veno-arterial, or arteriovenous hemoperfusion must be established. Unlike the first two options, arteriovenous blood perfusion does not require a blood pump to circulate blood through the dialyzer. Furthermore, this option allows for slow blood ultrafiltration.

To connect the dialyzer (ultrafilter) to the patient's Circulatory system, puncture of the femoral vessels, Internal jugular vein, or subclavian vein is performed.

When performing blood ultrafiltration for extracorporeal detoxification, the removed ultrafiltrate must be replaced with a substitution solution (0.9% NaCl or Ringer-lactate solution without potassium ions).

Hemoperfusion is extracorporeal blood purification by perfusing it through granulated or plate hemosorbents. Hemoperfusion is used for poisonings with OPUs, barbiturates, atropine, phenothiazine derivatives, pachycarpine, acetone, ethylene glycol, mushrooms, and carbon tetrachloride. The Use of this procedure at the pre-hospital stage significantly increases its efficacy, especially in poisonings with highly toxic agents. The overall effect of hemoperfusion is associated with the removal of poison and endogenous toxic substances from the blood, as well as the improvement of blood rheological properties and microcirculation.

Sorption is the uptake of gas molecules or solution components (adsorbates) by The surface of a solid or liquid (sorbent). The active (absorbing) surface area of the sorbent reaches 1000 cm²/g. During hemoperfusion, medium- and macromolecular toxins that are not removed by dialysis are eliminated from the body. Another advantage of hemoperfusion is its high rate of detoxification.

Following the necessary examinations and the decision to perform hemoperfusion, 400 ml of rheopolyglucin and 200 ml of 10% serum albumin solution are infused on the day of the procedure under blood pressure monitoring; if spontaneous drinking is difficult, 400-600 ml of Ringer's solution or 10% glucose solution with Insulin is administered.

This transfusion preparation improves microcirculation, reduces blood viscosity, and lowers the risk of sorbent granules "clumping" in the Column. In the presence of significant hypocoagulation (e.g., in cases of severe Liver failure), rheopolyglucin is excluded from the preparation regimen.

Vascular access is a crucial element of hemoperfusion therapy and depends on the physician's proficiency in utilizing various methods of connecting the apparatus to the patient's Vascular System.

If the physician is skilled in the Seldinger technique of vascular catheterization, repeated connections of the hemoperfusion system do not cause difficulties.

For premedication, 1 ml of 2% promedol solution and 1 ml of 1% diphenhydramine (dimedrol) solution are used.

5-10 minutes before THE START OF hemoperfusion, the patient is administered heparin in a dose determined by coagulogram parameters, calculated as 150–200 IU/kg of the patient's body weight. An increase in column resistance serves as an indicator for additional heparin administration. If bleeding occurs, excess heparin is neutralized with protamine sulfate (1 mg of protamine sulfate per 100 IU of heparin).

Hemoperfusion is typically performed in an intensive care unit or specially equipped operating rooms, which must be fully stocked with resuscitation supplies and medications necessary to support Cardiac Activity and manage hemodynamics.

In the absence of specialized equipment, hemoperfusion can be performed using a mini-perfusion system under an arteriovenous pressure gradient. In this case, an arteriovenous shunt is created. When performing hemoperfusion using SKN-type sorbents, a perfusion attachment with a slit filter must be used to prevent microparticles of the sorbent from entering the patient's vascular bed.

Before connecting the patient to the adsorption column, it must be rinsed free of carbon microparticles and dust, which are invariably present in the sorbent solution. For this purpose, 1.5 L of sterile isotonic sodium chloride solution should be prepared in advance. The sorbent is washed using a roller pump at a solution perfusion rate of 120-160 ml/min. Heparin in a dose of 500-1000 IU is added to the final 500 ml of the solution.

At the beginning of the hemosorption session, the perfusion rate is low—40-60 ml/min; it is then gradually increased to 80-120 ml/min under the control of blood pressure and heart rate. If pressure in the mass exchanger rises and There is a risk of column thrombosis, it must be rinsed with an isotonic sodium chloride solution containing heparin. The volume of blood perfused through the sorbent averages 1-3 BCC (blood circulating volume) and largely depends on the patient's general condition and blood resistance within the sorbent column.

Upon completion of hemosorption, the sorbent column is disconnected from the vascular blood access, and the blood from the system lines is returned to the patient's vascular bed.

Hemosorption should be used with extreme caution in organophosphate poisoning, as the procedure adsorbs not only the toxin but also cholinesterase. This necessitates the periodic administration of dipiroxime and isonitrozine.