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Carbon monoxide poisoning

 
, medical expert
Last reviewed: 22.10.2022
 
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What is carbon monoxide poisoning, only a few people know. On hearing another concept - "carbon monoxide poisoning", which is exactly the same thing. Such intoxication is very dangerous and often ends in death if measures are not taken in a timely manner. Moreover, the main danger lies in the fact that a person does not feel the presence of gas in the air, quickly loses consciousness and dies.

Carbon monoxide is a substance obtained as a result of incomplete combustion of carbon, which often occurs against the background of limited access to oxygen. Initially, we are talking about a gaseous substance without a characteristic aroma and color. Due to its lightness, gas tends to accumulate in the upper air layers - for example, closer to the ceiling.

Carbon monoxide poisoning is popularly called “burning out”: it is easy to get if you use gas and especially stove heating with violations, ignore safety precautions when working with a car in a garage, as well as during fires, etc.[1]

Epidemiology

Carbon monoxide poisoning is one of the most common intoxication lesions caused by exposure to gaseous substances. For example, in the United States, more than 2,000 people die each year from such poisoning, and this does not include cases associated with fires. From 2001 to 2003, more than fifteen thousand victims were hospitalized in intensive care units with a diagnosis of carbon monoxide poisoning. At the same time, intoxication was both accidental and intentional - with the aim of suicide. More than half of the patients suffered as a result of a malfunction in the exhaust heating system of the furnace.

Almost every second survivor of carbon monoxide poisoning has long-term mental disorders. [2]

Causes of the carbon monoxide poisoning

The most common sources of carbon monoxide poisoning are  [3]: [4]

  • working cars;
  • gas-fired water heaters;
  • gas ovens;
  • ovens and household gas hobs;
  • charcoal grills;
  • preserved blood products used for transfusion;
  • units used for pouring ice;
  • boats, motor devices, generators;
  • anesthesia devices that use a reversible absorbent circuit;
  • propane loaders;
  • zones of active fires, coal mines.

Risk factors

At the moment, carbon monoxide poisoning is recorded much less frequently than, for example, a hundred years ago, when houses were predominantly stove-heated. Nevertheless, there are a lot of sources of possible intoxication in our time:

  • residential premises heated by gas stoves, fireplace inserts;
  • baths;
  • car repair shops, garages;
  • manufacturing plants that use carbon monoxide;
  • fires in enclosed spaces such as elevators, shafts, basements, etc.

Particularly at risk are people living in houses with stove heating, motorists and car mechanics, miners, firefighters. Often the victims of carbon monoxide poisoning are mentally unstable people and those who regularly abuse alcohol.[5]

Pathogenesis

Carbon monoxide density indicators are 0.968 of the specific mass of air under natural conditions. The substance is able to easily penetrate into the bloodstream, where it combines with hemoglobin: carboxyhemoglobin is formed. The degree of affinity of hemoglobin and carbon monoxide is high, so CO is present mainly in the blood, and only in small amounts - up to 15% in tissues.

Carbon monoxide is released during intrahepatic decomposition of methylene chloride, with a maximum detectable concentration eight or more hours after the onset of intoxication. [6]

The defining effect of carbon monoxide in case of poisoning is the failure of such a property of hemoglobin as oxygen binding. As a result, even with an adequate partial pressure of oxygen, its content in the arterial flow is greatly reduced. In addition, carbon monoxide shifts the HbO 2 dissociation curve to the left, which leads to a decrease in oxygen transfer to tissues. The toxic effect of the gas is due not only to the formation of carboxyhemoglobin, but also to the formation of carboxymyoglobin, a compound of myoglobin with carbon monoxide. It is known that the compound directly changes the processes of cellular respiration. Over time, oxidative degradation of lipids develops, brain activity is disrupted.[7]

Symptoms of the carbon monoxide poisoning

The clinical picture of carbon monoxide poisoning has several degrees of severity, which are characterized by different manifestations and their intensity.

For a mild degree, the following first signs are characteristic:

  • a general state of weakness;
  • increasing pain in the head (more often in the forehead and temples);
  • sensation of pulse beats in the temples;
  • auditory noise;
  • dizziness;
  • visual impairment, veil, clouding;
  • dry cough;
  • feeling of lack of air, difficulty breathing;
  • tearing;
  • nausea;
  • redness of the skin of the face, extremities, conjunctiva of the eyes;
  • increased heart rate;
  • "jump" in blood pressure.

With moderate carbon monoxide poisoning, the symptoms increase and worsen:

  • clouded consciousness, the flesh to its loss;
  • vomiting appears;
  • auditory and visual hallucinations occur;
  • loss of coordination of movements;
  • there is a feeling of pressure behind the sternum.

In severe cases, other serious symptoms are added:

  • the functionality of the muscles decreases up to paralysis;
  • a person loses consciousness, a coma may develop;
  • convulsions appear;
  • pupils dilate;
  • possible involuntary excretion of urine and feces;
  • pulse weak and frequent;
  • skin and mucous membranes acquire a bluish tint;
  • respiratory movements become superficial and intermittent.

As you can see, the color of the skin during carbon monoxide poisoning varies depending on the degree of intoxication, ranging from deep red to cyanotic. With a fainting form, which refers to atypical manifestations of poisoning, the skin and mucous membranes may be pale and even grayish.

Less commonly, acute carbon monoxide poisoning manifests itself in the so-called euphoric form: the victim has psychomotor agitation, unreasonable laughter or crying occurs, and behavior becomes inadequate. Further, signs of respiratory and heart failure increase, the person loses consciousness.

Chronic carbon monoxide poisoning is characterized by complaints of constant pain in the head, fatigue, apathy, sleep problems, poor memory, periodic "failures" in orientation, frequent and unstable heartbeat, pain behind the sternum. Vision is disturbed: color perception changes, the visual field narrows, accommodation is disturbed. The symptoms of malfunctions from the central nervous system are growing, which manifests itself in the form of asthenia, dysfunctions of the autonomic nervous system, vascular spasms, hypertension, myocardial dystrophy. When conducting an ECG, focal and diffuse pathological signs, coronary changes are detected. In women, there are failures of the monthly cycle, problems with pregnancy. Men note sexual weakness.[8]

Chronic poisoning can become a trigger in the development of atherosclerosis, endocrine disorders: thyrotoxicosis is often found in patients.

Complications and consequences

It is difficult to predict the long-term consequences of carbon monoxide poisoning, since the compounds formed in the blood are quite strong. In addition, carbon monoxide can change the structure of hemoglobin, which negatively affects the mechanism of oxygen transfer to tissues. The transport properties of blood are disturbed, chronic hypoxia develops, which adversely affects the functional ability of the brain, cardiovascular system, liver and kidneys.

Carbon monoxide has a long-term toxic effect on all tissues in the body. This compound binds to myoglobin, disrupts the contractile function of the myocardium, which leads to poor blood circulation and lack of oxygen in the organs.

If we follow the statistics of intoxication, then a person who has survived carbon monoxide poisoning may die in a few years from a heart attack associated with myocardial damage.

Other adverse effects may include:

  • memory impairment;
  • deterioration of mental abilities;
  • myopathy;
  • migraine;
  • chronic dyspepsia.

According to experts, even after intensive treatment in persons poisoned by carbon monoxide, neurological disorders continue to be present for at least three years. The possibility of irreversible disturbances in cellular structures is also not ruled out.[9]

Causes of death from carbon monoxide poisoning

Coma and death of the victim usually occurs as a result of paralysis of the respiratory center. In this case, heart contractions can be recorded for some time after breathing stops. There are many cases of death from the effects of intoxication even a few weeks after the event.

Some patients develop complications in the form of inflammatory processes in the airways and lungs. Death from such complications takes the second place after oppression and paralysis of the respiratory center.

As a rule, a severe form of carbon monoxide poisoning ends in death. In the long term, negative consequences can develop after a moderate form of intoxication.

Diagnostics of the carbon monoxide poisoning

Since the clinical picture of carbon monoxide poisoning is most often vague, without varied and specific symptoms, it is easy for a medical specialist to make a mistake and make an incorrect diagnosis. There are many cases where moderate poisoning with blurred symptoms was mistaken for a viral infection. Therefore, doctors are advised to be very careful, and at the slightest suspicion of carbon monoxide poisoning, conduct a thorough diagnosis using all necessary procedures. For example, gas intoxication can never be ruled out if non-specific virus-like signs are found in patients living in the same residential area - especially if the house has stove or fireplace heating.

Tests are the basis for diagnosing carbon monoxide poisoning. First of all, the content of carboxyhemoglobin in the blood should be determined: for this purpose, a CO-oximeter is used. It is possible to take for research both venous and arterial blood. A high level of carboxyhemoglobin is a 100% indicator of carbon monoxide intoxication. But situations are known when this level is underestimated due to its rapid fall. For example, this happens if the victim is urgently evacuated from the gas source, or oxygen is inhaled on the way to the hospital (before taking blood for analysis).

Instrumental diagnostics is not decisive, but only acts as an addition to the diagnosis, as it helps to detect some auxiliary signs - for example, electrocardiography is performed for chest pain, and for neurological symptoms - computed tomography of the brain. Changes in the CT image are noticeable already 12 hours after carbon monoxide poisoning, which was accompanied by loss of consciousness. Usually, symmetrical rarefaction foci are visualized in the area of the pale ball, putamen, and caudate nucleus. Such changes that appeared during the first day indicate an unfavorable prognosis. And vice versa - the absence of pathological changes indicates a likely positive outcome.

Differential diagnosis is carried out with influenza and other viral infections, alcohol intoxication, overdose of sedative and hypnotic drugs.

Treatment of the carbon monoxide poisoning

The main focus of treatment for carbon monoxide poisoning is the establishment of gas exchange processes. First of all, the patient is provided with breathing with 100% oxygen using a mask or endotracheal tube. Such a measure helps to increase the concentration of dissolved oxygen in the bloodstream, while simultaneously stimulating the dissociation of carboxyhemoglobin. If hospitalization and oxygenation are followed in a timely manner, the mortality rate is reduced to 1-30%.

Primary treatment measures may include:

  • setting up an oxygen mask;
  • breathing with a mixture of oxygen and carbon dioxide (the so-called carbogen);
  • artificial ventilation of the lungs;
  • chamber therapy.

In addition, an antidote is mandatory.

After stabilization of the victim's condition, they begin general treatment in order to restore the basic functions of the body and prevent the negative consequences of hypoxia.

In addition to the main treatment, a diet is prescribed: food is enriched with fortified food rich in antioxidants. The diet should include a dominant amount of fruits and berries: blueberries, red and blue grapes, cranberries, currants, and pomegranates are recommended. Freshly squeezed juices from citrus and carrots, green tea, pu-erh have a good effect. [10]

First aid for carbon monoxide poisoning

The prognosis for the patient directly depends on the speed and timeliness of first aid, so even if you suspect carbon monoxide poisoning, you should immediately contact an ambulance.

General first aid measures are as follows:

  • Eliminate and neutralize the source of carbon monoxide release, the poisoned person is taken out or taken out to fresh air.
  • They provide oxygen access to the maximum: loosen the collar, unfasten the belt, etc.
  • They try to activate blood circulation: rub the chest, give hot tea or coffee to drink.
  • In every possible way they prevent the loss of consciousness of the victims: they bring ammonia, spray with cool water, slap on the cheeks.
  • If the victim's breathing has stopped, or the pulse has disappeared, emergency measures should be taken: artificial respiration, manual heart massage.

Antidote for carbon monoxide poisoning

The antidote is Acizol, which is administered in an amount of 60 mg as an intramuscular injection three times during the first 24 hours of poisoning, then once a day in an amount of 60 mg for two consecutive days. The introduction of an antidote is combined with fibrobronchoscopy in case of damage to the respiratory system.

If the victim can take the drug on his own, then it is prescribed in the form of capsules: one capsule 4 times on the first day, then one capsule twice a day for a week. The maximum allowable dosage of an antidote for an adult is 4 capsules (or 480 mg).

Acizol enhances the effect of general pathogenetic treatment, inhibits the formation of carboxyhemoglobin by influencing the combined interaction of hemoglobin subunits. As a result, the degree of relative affinity of hemoglobin and carbon monoxide decreases, and the oxygen-binding and gas-transporting abilities of the blood are optimized. In addition, the antidote reduces the degree of oxygen starvation, increases the hypoxic resistance of the body. [11]

Medications that a doctor may prescribe

Carbon monoxide poisoning always requires urgent hospitalization, even if the victim appears to be doing well. In addition to oxygen therapy, the patient is given an intravenous infusion of drugs, depending on which organs and systems failed first. Often prescribe cardiovascular drugs, vitamins, anticonvulsants, etc.

Anti-inflammatory drugs to eliminate airway inflammation

Pulmicort

A glucocorticosteroid drug with a strong anti-inflammatory property that reduces the degree of bronchial obstruction. The dosage for an adult patient is up to 800 mcg per day, taken for 2-4 inhalations. The amount of the drug can be changed at the discretion of the doctor. Among the possible side effects: allergies, sleep disturbance, cough, irritability.

Budesonide

An active synthetic glucocorticoid drug that prevents and cures inflammatory diseases of the respiratory tract. It can be prescribed in an amount of 200 to 1600 mcg per day, for 2-4 inhalations. Possible side effects: candidiasis of the mouth and throat, hypersensitivity reactions, cough, wheezing, throat irritation.

Anticonvulsants to reduce muscle hypertonicity

Levodopa and carbidopa

Anticonvulsant antiparkinsonian agent, prescribed in individual dosages. Can be used from 18 years of age.

Amantadine

Antiviral and at the same time antiparkinsonian drug. It is taken orally, after meals, in an individually selected dosage. Treatment may be accompanied by nausea, dry mouth, dizziness. Simultaneous intake of alcohol and Amantadine is prohibited.

Painkillers for relief

Novigan

Analgesic and antispasmodic. It is prescribed between meals, one tablet three times a day. Contraindicated in children under 16 years of age. Possible side effects: abdominal pain, allergic reactions, dyspepsia.

Ibuprofen

Non-steroidal anti-inflammatory drug, taken after meals, 200-400 mg, three times a day. The duration of treatment is no more than three days. Side effects: abdominal pain, indigestion.

Vitamin preparations to accelerate the destruction of carboxyhemoglobin

Cocarboxylase

Vitamin B 1 preparation, which is used as part of complex treatment. Enter intramuscularly at 50-100 mg per day, for 15-30 days in a row. During treatment, allergic reactions are possible in the form of redness, itching, swelling.

Sorbent means for neutralization of toxins

Polysorb

Preparation of colloidal silicon dioxide with enterosorbing activity. Take between meals, in individual dosages. Treatment can last up to two weeks. It is possible to conduct several courses with an interval between them of 2-3 weeks. Side effects are rarely recorded: it can be constipation, allergies.

Prevention

In order to reduce the risk of carbon monoxide poisoning, it is recommended to adhere to the following simple rules:

  • the operation of stoves and fireplace inserts must be carried out in compliance with all safety regulations;
  • you need to regularly inspect and test the ventilation system in the house, check the patency of the chimney and ventilation ducts;
  • installation of stoves and fireplace inserts, their repair and maintenance should be carried out only by professional specialists;
  • you can turn on the car engine only in an open garage (according to statistics, to get carbon monoxide poisoning, it is enough to stay in an enclosed space with the engine running for five minutes);
  • you can’t stay in a standing, closed, running car for a long time, and moreover, sleep in it;
  • for any signs of the spread of carbon monoxide and carbon monoxide poisoning, it is important to fill the room with fresh air as soon as possible, and if possible, go outside.

Carbon monoxide is an insidious and dangerous substance that has a quick and almost imperceptible effect. Therefore, it is much easier to prevent a problem in advance by simply following all the rules and recommendations.[12]

Forecast

What do experts say about the prognosis of the clinical course of acute carbon monoxide poisoning? In most cases, such a prognosis depends on how affected the respiratory tract is, as well as on the fixed maximum level of carboxyhemoglobin in the blood of the victim. Doctors assess the condition of the victim using the following criteria:

  • general health, individual characteristics of the patient's physiology (the worst prognosis is voiced for debilitated patients suffering from chronic pathologies, for the elderly, pregnant women and children);
  • the duration of exposure and the concentration of carbon monoxide in the air breathed by the victim;
  • vigorous activity during intoxication (high physical activity, intense respiratory movements contribute to the more rapid development of poisoning).

Unfortunately, often acute carbon monoxide poisoning ends in death: this is due both to the vagueness of clinical symptoms and the lack or untimely provision of first aid to the victim.

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