CARBON MONOXIDE

From Big Medical Encyclopedia

CARBON MONOXIDE (synonym carbon monoxide gas) — carbon compound with oxygen (CO), is toxicant.

The lake at. — colorless gas, inodorous, in usual conditions does not react with water, acids, alkalis. It is formed at incomplete combustion of organic compounds, and also at interaction of carbon dioxide gas with the heated coal. Burns with a blue flame at t ° 700 — 1000 °.

The lake at. is a part of industrial gases (generating, domain), to-rye receive in gas generators by incomplete combustion of coal, coke and other hydrocarbons. In minute quantities is available in the atmosphere, volcanic and firedamp. It is eurysynusic in life, contains in exhaust gases of internal combustion engines, in explosive gases, etc.

Danger of intoxication of O. at. arises at receipt it in air. Such situations are possible in domain, martin, forge and foundry workshops, in mines and mines after blasting, on coke-chemical and coke and gas plants, in garages, railway tunnels, and also on chemical productions where O. at. is a starting material for receiving ammonia, acetone, methyl alcohol, phosgene, etc. Cases of poisonings Oh, at. are possible during the roasting of a brick and cement, on bakeries, at fermentation of tobacco and on other productions where the wrong fire chamber of furnaces can take place (insufficient receipt in a fire chamber of air or oxygen). In considerable concentration of O. at. can collect in premises during the use of faulty gas stoves, in air of city highways with heavy traffic of transport.

The lake at. is a metabolic product in an organism and contains in trace amounts in blood and fabrics.

High affinity of O. at. to bivalent iron of hemoglobin, a cut almost by 300 times surpasses affinity of hemoglobin to oxygen causes its toxic action on an organism. The lake at., forcing out oxygen from its connections with hemoglobin, forms carboxyhaemoglobin (HbCO). At the same time a part of hemoglobin becomes not active that breaks transport of oxygen in fabric and leads to development of oxygen insufficiency — hypoxias (see).

The number of the formed HbCO is proportional to the partial pressure of O. at. and in inverse proportion to pressure of oxygen in inhaled air. At decrease in maintenance of O. at. in inhaled air process of dissociation of HbCO begins, to-ry generally comes to an end in 7 — 9 hours after single influence of O. at. As Y. Henderson and H. W. Haggard specify, there is a dependence between saturation rate of HbCO blood and a wedge, symptoms of intoxication (see the table).

By data A. M. Rashevskoy, formation of HbCO is followed by decrease in the oxygen content in an arterial blood with 20 to 12 about. %, decrease in an arterial and venous difference to 4 — 2 about. % (instead of 6 — 7 about. the % is normal), decrease in content in blood of carbon dioxide gas with 45 to 35 about. %. Significantly activity of the available HbO decreases fiziol, 2 .

At O.'s poisoning at. along with a hypoxia there is a reduction in blood of a transport form of iron. Besides, O. at. at bigger concentration in blood has direct toxic effect on cells of fabrics, tissue respiration in a cerebral cortex oppresses, exerting inhibitory impact on cytochrome - enzymatic system.

The hypoxia and a carboxyhaemoglobinaemia excite reflexes from carotid balls, exerting the expressed impact on a metabolism and a condition of endocrine and vegetative system.

The maximum allowable concentration of carbon monoxide in air of a working zone makes 20 mg/m 3 . During the work no more than 1 hour exceeding of maximum allowable concentration to 50 mg/m is allowed 3 , during the work no more than 30 min. — to 100 mg/m 3 , no more than 15 min. — to 200 mg/m 3 . Maximum one-time maximum allowable concentration in free air of 6 mg/m 3 , average daily — 1 mg/m 3 , maximum allowable concentration for premises of 2 mg/m 3 .

A clinical picture of poisonings

Acute poisoning of O. at. develops most often at its concentration in air exceeding 100 — 200 mg/m 3 , and poisoning with a collapse depending on an individual condition of an organism at concentration of 400 — 600 mg/m 3 in 2 — 5 hour. At higher concentration acute poisoning develops in a few minutes. It is characterized by a complex a wedge, symptoms from c. N of page, respiratory organs, cardiovascular system and blood. Disturbances of c. N of page come down to emergence of dizziness, headache, excitement, confusion of consciousness, in hard cases there comes the loss of consciousness and a collapse. The most serious poisoning causes bystry development of a coma, is frequent from the death.

Coma is characterized by muscle tension of extremities, clonic and tonic spasms, an involuntary urination and defecation, the person of bright red color, cyanosis of extremities is noted. At a serious poisoning also skin and trophic frustration — an erythema, hypostases are observed. Visual disturbances — disturbances of photoperception, change of fields of vision, a xanthopsia are in some cases observed.

Disorder of breath is expressed usually by the asthma which is replaced further by the urezheniye of breath caused by a hypocapny as a result of a hyperventilation. The cases of toxic pneumonia arising on 2 — after poisoning as a result of a hypoxia of the pulmonary fabric reducing resilience to an infection are sometimes observed the 3rd day. Rentgenol, changes of lungs: emphysema, diffusion macrofocal blackouts and strengthening of the pulmonary drawing.

Heartbeat, increase of pulse, emergence of arrhythmia, expansion of borders of heart, dullness of tones, the phenomena of stenocardia are characteristic, in some cases myocarditis, a myocardial infarction can develop.

In blood small increase in quantity of erythrocytes, delay of ROE, the expressed neutrophylic leukocytosis with band shift and a limfoeozinope-niya is observed.

The mental disorders observed at O.'s poisoning at., depend on its concentration. At slight poisonings observe obnubilation of consciousness (see. Devocalization ) with complaints to headaches, dizziness, a sonitus, nausea, etc. At moderately severe acute poisonings the oglushennost gradually accrues before dead faint, quite often there are clonic spasms or epileptic seizures. After escaping of unconsciousness delirious frustration (quite often long), pictures of a twilight state prevail. Also subacute crazy psychoses with the unsystematized ideas of prosecution and influence, catatonic pictures with negativism and a condition of chaotic excitement with impulsive and aggressive acts are described (see. Catatonic syndrome ).

After a «light» time term, free from mental disturbances, lasting from several days up to several weeks the stage of mental changes can develop so-called hron. Patients become excited again, then symptoms of devocalization join, and on their minovaniya anamnestic frustration and confusion of consciousness accrue. Sometimes crazy (schizoformous) psychoses develop hron. The mental disorders arising at the remote stage of poisoning, as if in the form of a recurrence possess various degree of reversibility. Development of mental weakness (superficial dementia) of anamnestic type is observed especially in those predictively adverse cases when mental disturbances are combined with development of signs of organic lesion of a brain (in the form of parkinsonism and rigidity, amyostatic - an akinetic syndrome with an amimia and prehensile avtomatizm, is more rare than horeatichesky and atetozopodobny hyperkinesias, aphotic, apraktichesky and agnostic frustration). Are characteristic of such cases and the phenomenon of a polyneuritis (sharp extremity pains) with full inversion of a dream.

An opportunity hron, O.'s poisonings at. one researchers dispute, others consider it result of repeated slight acute poisonings. Development of an asthenic syndrome with strengthening of tendon jerks, emergence of a tremor a century, language, fingers of hands, dysfunctions of a thyroid gland, increase in blood of quantity of erythrocytes and hemoglobin is undoubted. The investigation hron, intoxications, according to a number of researchers, can be also trophic disorders of skin, arrhythmia and premature ventricular contraction, the stenokardichesky phenomena.

First aid and treatment

At O.'s poisoning at. it is necessary to bring the victim to fresh air and to begin plentiful inhalation of oxygen. In hard cases carry out bloodletting with the subsequent intravenous administration of 20 — 30 ml of 40% of solution of glucose. At disturbance of breath enter lobeline (1 ml of 1% of solution) or Cytitonum (1 ml), cardiovascular means. At a coma — intravenous administration methylene blue (10 ml of 1% of solution), at an apnoea — an artificial respiration, at spasms — phenobarbital (0,1 g), enemas from 2% solution of Chlorali hydras, bromides. Iron preparations are recommended (ferkoven).

Forecast O.'s poisonings at. depends on its concentration in air and time of stay in an area of coverage of O. at. The forecast of the acute poisoning proceeding with mental disorders is serious. Recovery occurs only in half of cases, often various psychotic pictures of a stage of acute poisoning pass into a long anamnestic syndrome (see. Korsakovsky syndrome ).

Prevention

For decrease in concentration of O. at. in air of a working zone carry out sealing of the equipment, pipelines, bystry removal of the allocated O. at. by means of ventilation. Are necessary constant control behind O.'s concentration at. in air, especially in gas dangerous places, control of tightness of the equipment and fight against a gas leak, including in living conditions. Importance in the prevention of poisonings of O. at. the correct organization has gas-rescuing service (see).

For individual protection the filtering gas mask of the SO brand is under production conditions recommended; at joint presence of O. at., chlorine, dust — a gas mask of the DRIED brand. The gas mask of brand M is suitable in the presence in air and other gases. The gas mask of brand of Ministry of Railways-F protects from combined action of carbon monoxide and sulfur dioxide gas. At very high concentration of O. at. in air self-rescuers (SP-9, SP-55), and also the oxygen isolating gas masks use.

Definition in air

Qualitative test of O. at. it is based on O.'s reaction at. with palladium chloride. For this purpose the filtering pieces of paper impregnated with 1% solution of palladium chloride are dried up, then they are moistened with 5% solution of sodium acetate — in the presence of O. at. in air of a piece of paper blacken.

Carbon monoxide in the medicolegal relation

In court. - medical practice should meet cases of fatal acute poisoning of O. at., generally as a result of accidents at the fire, emergency leak of household gas, violation of the rules of a fire chamber of furnaces, during the operation of internal combustion engines in garages. The prof. of poisoning and O.'s suicide at. meet seldom.

At inspection of the scene special attention is paid on a condition of gas-conducting, torches, gates of furnaces, availability of the smoldering coals in fire chambers of furnaces, a flocculent soot and foreign smells indoors where the victim is found. At group poisonings of different weight it is necessary to consider location of everyone since the people who appeared on a floor can be exposed to a lesser extent to toxic action of O. at., because it is easier than air. Before inspection of the scene measure O.'s concentration at. indoors, where there was poisoning. At investigation of poisonings, work-related engines, note an arrangement of the victim (a cabin, a body, a garage) and the vehicle, a condition of its engine (it is included and works; it is included, but does not work due to the lack of fuel). At external examination of a corpse note bright red livors mortis and a well-marked cadaveric spasm. Blood liquid, bright red color; same color plethoric internals and skeletal muscles. The brain and a soft meninx are edematous. Under a pleura, a peritoneum, an epicardium multiple hemorrhages; the same hemorrhages find in internals. In a brain, heart, a liver, kidneys — dystrophic and necrotic changes, character and expressiveness to-rykh depend on time which passed after death.

At suspicion to death from O.'s poisoning at. preliminary assays on HbCO are carried out. Tests carry out on slide plates or plates: apply with a glass rod on one drop the studied and control blood; by means of a pipette add to them on one drop of the corresponding reactant and mix the different ends of a glass rod. The blood containing O. at., does not change color; the control drop of blood at Goppe-Zeyler's test (or the GAME) changes the color from 33% of NaOH on brown due to formation of alkaline hematin; at Liebman's test (with solution of formaldehyde) blood gets brown-black coloring due to formation of a formalin pigment; at Zalessky's test (with konts. solution of cuprous sulfate) gains green color. At Sidorov's test on distillate add to 2 ml of 10% of solution of blood on 3 — 5 drops 20% of solution of yellow blood salt and 0,01% of solution of potassium bichromate, carefully mix. The solution supporting HbCO gets carminic-red coloring, HbO 2 — brownish-green. At test Kuhn-kelya — Vettsel to several milliliters of the studied blood add triple water volume to a test tube and about 1/3 on the volume of 1 — 3% of tannin, stir up mix and leave time on a nek-swarm; the formed deposit has bright red color (in control blood the deposit gets brown-red coloring). At a spectral research by means of spectroscopes of direct vision in probirnut bring several drops of blood, part it with water till light pink color, observe a spectral picture, then add sodium hydrosulphite or other reducer.

The range of blood supporting HbCO will not change, in control due to formation of the got into condition N 2 strips of absorption in a flavovirent part of a range will be replaced with one wide.

In diagnosis of poisoning of O. at. results court are important. - chemical definitions of carboxyhaemoglobin (HbCO) in blood and carboxymyoglobin in muscles of the dead. O.'s presence at. in blood and muscles is established by the qualitative tests based on change physical. - chemical properties of blood under the influence of O. at., a spectral research (on detection of ranges of carboxyhaemoglobin and carboxymyoglobin). The quantitative maintenance of O. at. in blood and muscles is established photo and spectrophotometric methods (see. Spektrofotometriya ). O.'s maintenance at. in blood and its quantity establish by also gazokhromatografichesky method (see. Chromatography ).

During opening for court. - chemical researches take 100 ml of blood from cardial cavities or large vessels and store it prior to a research under a layer of a liquid paraffin on cold. During the use of modern gazokhromatografichesky methods of a research only 1 — 1,5 ml of blood there are enough. High-quality establishment of HbCO is possible also at a research of the dried-up blood and blood spots. The court is at the same time made. - a chemical research of muscular tissue on existence and quantitative content of carboxymyoglobin. 50 — 100 g of skeletal muscles are necessary for definition of carboxymyoglobin. Connections O. at. with haemo - and a myoglobin of a rack; they can be found in corpses through a long time after death.

At acute poisonings the maintenance of HbCO in blood can reach to 50 — 60 and even 100%. Death usually comes from paralysis of breath at substitution of 70 — 80% of hemoglobin with carboxyhaemoglobin. At very high concentration of O. at. in the environment the «instant» form of poisoning which is coming to an end with bystry death, sometimes after several breaths is observed. Considerable decrease in number of HbCO in blood is noted at its heating therefore detection of small amounts of HbCO in blood of the corpses treated to action of high temperature during the fire is not excluded. Sometimes a negative take of a chemical research at notorious poisoning of O. at. it is connected with bystry approach of death or with bystry removal of the victim from the atmosphere containing the increased O.'s concentration at.

Table. Dependence between saturation rate of blood carboxyhaemoglobin (HbCO) and clinical symptoms of intoxication carbon monoxide

Bibliography: Avdeev M. I. Forensic medical examination of a corpse, page 375, M., 1976; Harmful substances in the industry, under the editorship of N. V. Lazarev and I. D. Ga-daskina, t. 3, page 240, L., 1976; Bushes V. V., Tiunov L. A. and Vasilyev G. A. The combined effect of industrial poisons, M., 1975; Occupational diseases, under the editorship of. A. A. Le-taveta, page 245, M., 1973; T and at N about in L. A. and Kustov of V. V. Toksikologiya of carbon monoxide, L., 1969; M and uyeg - Gross W., Slater E. Roth M. Clinical psychiatry, p. 338, L., 1960.


A. V. Roshchin; V. V. Tomilin (court.), E. Ya. Shternberg (loony.).

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