ENDOGENOUS ENDOGENOUS INTOXICATION IN SURGERY Endogenous intoxication (autointoxication) is a syndrome typical of many pathologic processes and conditions due to a massive arrival of various various toxins into the body’s internal environment. These toxins are contained in the body in normal conditions as well but their concentration is always controlled by the protective and corrective system of homeostasis. From the course of physiology you know that any body can exist only if the body’s composition is maintained within within certain limits. Claud Bernard, Bernard, the great French physiologist, formulated this in the following way: “The stability of the internal environment is a necessary condition for a free life of the body”. In normal conditions the immune system recognizes foreign bodies, fixes them with antigen-antibody-complement complexes, detains them in lymphoid tissue, subjects to phagocytosis and destruction by lysosomal enzymes; the liver and intestine inactivate a great amount of liposoluble toxic substances which under the impact of chemical reactions convert to hydrophilic ones and are excreted by kidneys. The lungs eliminate carbon dioxide, water, volatile toxic substances, and metabolic products of aggressive fluids. If any organ begins to dysfunction, its functions are partially taken over by other systems. For instance, when hepatic failure develops and metabolites for whose disposal the liver is responsible accumulate in the blood and tissues, the load on the kidneys and lungs increases which partially compensates for the toxemia. The same happens in uremic intoxication when the excretion of products through the intestine and lungs increases. Polyorganic insufficiency syndrome is significant in this respect, too, when it does not matter which organ began to dysfunction as all systems are gradually involved into the pathologic process. The amount of affected organs and systems has clinical importance as this constitutes the foundation of prognosis: in insufficiency of one organ or system mortality is about 23-40%; of two organs or systems – 53-60%, three and more – 73-89%. Nowadays the study of endogenous intoxication is of great importance. importance. Estimation of the severity of autointoxication is important for a correct choice of therapy for this condition. For a long time intoxication in all spheres of medicine was managed with detoxication therapy. It is widely used nowadays as well. You are sure to know what it consists in: transfusion of various solutions: of glucose, Ringer’s, saline. In more severe conditions the method of forced diuresis is used when the patient receives diuretics after infusion of a large amount of fluid (3-5 litres). Not so long ago blood transfusion was undertaken for the purpose of detoxication (your textbook mentions this). It has been noticed, however, that when a certain critical level of intoxication is reached, detoxication is no longer of use. The mechanism of action of detoxication therapy is based on diluting toxic substances with the administered solutions (of glucose, saline) or fixing them (refortan) with subsequent destruction or excretion. But in autointoxication the organs responsible for detoxication and excretion have to cope with a heavy
burden as it is, so in severe cases there is little hope that these organs can succeed on their own. There is a need for such methods that could either completely neutralize the toxins or excrete them from the body in another way. These methods were sought for empirically at first; in late 1970-s, early 1980-s a new specialty in medicine emerged, efferent therapy (from the Latin word ‘efferre’ – to carry away). Mankind has long been using various procedures to remove harmful substances. Charcoal and ash were used to powder wounds, they were eaten upon poisoning (coal can absorb many toxic substances). Blood-letting and leeches were popular for many various conditions. But efferent methods were really developed at the beginning of the 20 th century. In 1913 Abel proposed a therapy for detoxication which can be regarded as the prototype of artificial kidney. He used animal intestinal wall treated with formalin as semipermeable membrane. At the same time ultraviolet irradiation of blood in patients with sepsis was proposed; although there were no antibiotics then the outcome was favourable, the patient recovered. From mid-30s these methods were forgotten as pharmacology began its rapid development and the physicians’ interest was mainly directed at this sphere. It is obvious now that drug therapy alone cannot solve all the problems. Along with indisputable success of drug therapy its downsides are apparent now: - rise of allergic diseases; - drug tolerance; - psychological and physiologic dependence of some patients on drugs. This led to the new stage of development of non-medicamentous methods of treatment. In their relation to the body’s own detoxication system these methods are divided in the following way: - Methods enhancing the processes of natural cleansing. - Artificial detoxication, the possibility of temporary replacement of disrupted functions. - Special antidote therapy. Enhancement of natural cleansing processes 1. Cleansing of the gastrointestinal tract - emetic drugs - gastric lavage (regular or with a tube) - intestinal lavage (intestinal lavage, enema) - laxative drugs (magnesium salts, castor oil) - electric stimulation of intestinal peristalsis 2. Infusion therapy and forced diuresis 3. regulation of enzymatic activity (festal) 4. therapeutic hyperventilation of lungs (upon poisoning with substances excreted through the lungs)
5. therapeutic hyperthermia and hypothermia (sauna for stimulation of
metabolism, therapeutic pyrogens; hypothermia as prevention of hypoxic intoxication in surgery with replaced circulation. 6. hyperbaric oxygenation. Artificial detoxication 1. Afferent methods (based on mechanical removal of toxins together with blood components and subsequent dilution of blood). - Blood substitution (exchange transfusion in newborn babies with hemolytic anemia). - Plasmapheresis (discrete and continuous). - Drainage of thoracic lymph duct and all types of lymph outflow stimulation. 2. Dialysis and blood filtration through semipermeable membranes - hemodialysis (artificial kidney is a method based on using membranes permeable for only low molecular toxins) - hemofiltration and membrane plasmapheresis (with membranes that are permeable to only water end electrolyte and catch corpuscular elements) - ultrafiltration with membranes with small pores permeable to only water and electrolytes (in fluid retention, anasarca, eclampsia) 3. Sorption methods based on using sorbents, substances that fix toxins. Most often it is sorbents consisting of active carbon. - Extracorporeal sorption (hemosorption, plasmasorption, lymphosorption, liquisorption). - Enterosorptrion, intracorporeal method. The sorbents are active carbon, polyphepam, enterosgel (natural sorbents are bran and cellulose). This method fixes toxins formed in the intestine after arrival there from blood (up to 12 litres of fluid secreted in the body passes through the intestine a day). - Vulneosorption, local method. Special sorbents (emosgent) or dressings of fabrics based on carbon fibres are used. 4. Electrochemical methods are based on electrolysis of solutions and subsequent oxidation of toxins. - Electrolytic oxidation. Indirect electrochemical oxidation is possible. Electrolysis yields an unstable solution which upon passing to blood stream releases active oxygen which oxidizes the toxins. For instance sodium hypochlorite can be used: NaCl – NaClO which then breaks down to NaCl and O 2. - Ozone therapy and ozonation of solutions. O2 + O = O3. The saturated O3 solution is transfused to the patient, in the blood stream O 3 breaks down and the released active oxygen oxidizes the toxins. O 3-enriched solution can be used for management of wounds. 5. Quantum therapy (physiohemotherapy, irradiation or photomodification of blood). The detoxicating effect of these methods is not very pronounced. It is mostly brought about by the immune system indirectly.
Ultraviolet radiation of blood. Many methods of ultraviolet radiation of blood have been proposed. The first ones consisted in irradiating blood drawn into a vial with bactericidal lamps. Then the continuous-flow method was developed when the blood was irradiated flowing through a tube of quartz glass. The main question in any method is the choice of optimum radiation dose as an overdose causes a condition like excessive sun exposure in spring. The physical significance of blood irradiation consists in: 1) the photon is absorbed by molecule and atom and passes to a higher orbit (stimulated condition); 2) reversal to usual condition giving energy to the tissues and stimulating physical and chemical processes in organs and tissues. Thus blood acts as a carrier of photon energy. Physical and chemical processes in the tissues are as follows: a change of energetic activity of biological membranes, conformation changes of molecules, formation of photolysis products. This induces biological response of tissues: inflammation stages become shorter, edema reduces, oxygen consumption by tissues increases, blood flow gets faster, rheological properties of blood improve etc. It has been proved that different wavelength in UV band cause different response of tissues. The shorter the wavelength, the greater the photon energy. The longer part of UV spectrum affects rheological properties of blood more, the shorter one inactivates the toxins and has a bactericidal effect. - Laser irradiation is a still more complicated question. The laser beam is different from light in that it is monochromatic and coherent. Laser irradiation can be different: 1. According to the wavelength and the source of laser energy. In UV part of spectrum CO2 lasers irradiate In the visible part of spectrum – ruby, sapphire, helium-neon lasers, cuprumvapour laser. In the infrared part gallium arsenide lasers work. 2. According to their capacity: High energy surgical lasers (flux >10 Watt/cm) cut tissues and are used in surgery Medium energy lasers coagulate and evaporate tissues (flux 0.4 – 10 watt/cm) Low energy (therapeutic) lasers are used for blood irradiation. 3. According to the continuity of irradiation Continuous ad impulse lasers 4. According to their focus – focused and unfocused lasers. For detoxication and immunostimulation purposes low energy lasers are often used; they operate in the visible and infrared part of the spectrum. 5. The methods of magnetotherapy and membrane oxygenation of blood stand somewhat apart. However, considering that they are mostly used in combination with efferent methods we should discuss them as well. -
When blood and tissues are exposed to magnetic field the rate of some chemical reactions changes. The clinical effects are reduced blood clotting and improved microcirculation. Membrane oxygenation of blood is used for extracorporeal saturation of blood with oxygen which makes it possible to saturate blood with oxygen when the lungs are not functioning (in severe lung edema). Nowadays detoxication methods develop in the direction of their combination. For instance, hemosorption is combined with ultraviolet irradiation of blood; plasmapheresis – with laser irradiation of blood, membrane oxygenation – with hemosorption and ultraviolet irradiation; hemosorption – with ultrafiltration. There are many such combinations; they are chosen individually in each case depending on the pathogenesis. As in autointoxication the treatment must affect different pathogenetic factors, combined treatment yields the best results. Efferent therapy is not an independent method of treatment; it is combination of surgical treatment, drug therapy and efferent methods that yields the best results.
