How Long Does Carbon Monoxide Stay in Your System?

Carbon monoxide poisoning

Carbon monoxide or carbon monoxide (chemical formula CO) is an extremely poisonous, colorless gas. It is an essential product of incomplete combustion of carbon-containing substances: it is determined in automobile exhaust gases, cigarette smoke, in smoke during fires, etc. Carbon monoxide does not smell.

Therefore, it is impossible to detect its presence and estimate the concentration in the air we breathe.

Getting into the blood, carbon monoxide displaces oxygen from the connection with the respiratory protein by hemoglobin and inhibits the functioning of the active centers responsible for the formation of new hemoglobin, thereby causing acute oxygen starvation of the tissues. Also, carbon monoxide disrupts the oxidative processes in the body.

Carbon monoxide, which has a high affinity for the respiratory protein, is much more active than oxygen. For example, if the CO concentration in the inhaled air is only 0.1% of the total volume (the ratio of carbon monoxide and oxygen is 1: 200, respectively), hemoglobin will bind equal amounts of both gases, i.e. half of the respiratory protein circulating in the systemic circulation will be occupied by carbon monoxide gas.

The breakdown of the carboxyhemoglobin molecule (hemoglobin-carbon dioxide) occurs about 10,000 times slower than that of oxyhemoglobin (hemoglobin-oxygen), which causes the danger and severity of poisoning.

Automobile exhaust gases contain a maximum of 13.5% carbon monoxide, an average of 6-6.5%. So, low-power motor in 20 liters. With. Produces up to 28 liters of CO per minute, creating in a closed room (garage, repair box) a deadly concentration of gas in the air for 5 minutes.

Typical symptoms of poisoning appear after 2–6 hours of inhalation of air containing 0.22–0.23 mg of carbon monoxide per 1 liter; severe poisoning with loss of consciousness and death may develop after 20-30 minutes at a concentration of carbon monoxide of 3.4-5.7 mg / l and after 1-3 minutes at a concentration of poison 14 mg / l.

How does carbon monoxide poisoning happen?

Carbon monoxide poisoning most often occurs in the following cases:

  • improper operation or malfunction of furnace equipment, gas heaters;
  • stay in a non-ventilated closed room with the car engine turned on;
  • fire;
  • smoldering electrical wiring, household appliances, interior parts, and furniture;
  • violation of safety when working in the chemical industry, which uses carbon monoxide.

The likelihood of poisoning is directly proportional to the concentration of carbon monoxide in the inhaled air and the time of its impact on the body.

How Long Does Carbon Monoxide Stay in Your System?

Carbon monoxide gas leaves the body the same way it got in, through the lungs. In fresh air, it takes four to six hours for a victim of carbon monoxide poisoning to exhale about half of the inhaled carbon monoxide in their blood.

Symptoms of poisoning

The nervous system is most sensitive to changes in the level of oxygen in the blood. The degree of damage can vary from mild reversible to generalized, entailing temporary or permanent disability, and in severe cases – the death of the victim.

In addition to the nervous system, the respiratory (tracheitis, tracheobronchitis, pneumonia) and cardiovascular (degeneration and necrotization of the myocardium, degenerative changes of the vascular walls) system are most often involved in the pathological process.

Depending on the concentration of CO in the air and, accordingly, carboxyhemoglobin in the blood, there are several degrees of carbon monoxide poisoning.

Symptoms of mild poisoning (the content of carboxyhemoglobin in the blood does not exceed 30%):

  • consciousness saved;
  • compressive, pressing headache resembling a hoop;
  • dizziness, noise, ringing in the ears;
  • lacrimation, profuse discharge from the nose;
  • nausea, vomiting;
  • slight transient visual disturbances are possible;
  • difficulty breathing;
  • sore throat, dry cough.

Poisoning of moderate severity (develops when the concentration of carboxyhemoglobin in the blood is from 30 to 40%):

  • short-term loss or other impairment of consciousness (stunning, soporous or coma);
  • difficulty breathing, intense shortness of breath;
  • persistent dilation of the pupils, anisocoria (pupils of different sizes);
  • hallucinations, delusions;
  • tonic or clonic convulsions;
  • tachycardia, pressing pain behind the sternum;
  • hyperemia of the skin and visible mucous membranes;
  • discoordination;
  • visual impairment (reduced acuity, flashing flies);
  • reduced hearing acuity.

In severe poisoning (the concentration of carboxyhemoglobin 40-50%):

  • coma of various depths and durations (up to several days);
  • tonic or clonic convulsions, paralysis, paresis;
  • involuntary urination and defecation;
  • weak, thready pulse;
  • shallow, intermittent breathing;
  • cyanosis of the skin and visible mucous membranes.

In addition to the classic manifestations of carbon monoxide poisoning, atypical symptoms may develop in one of the following forms:

  • unconscious – characterized by a sharp decrease in blood pressure (up to 70/50 mm Hg and below) and loss of consciousness;
  • euphoric – sharp psychomotor agitation, reduction of criticism, the disorientation of orientation in time and space, hallucinations and delusions are possible;
  • Fulminant – develops at a CO concentration of 1.2% or more in the inhaled air, the content of carboxyhemoglobin in the systemic circulation, in this case, exceeds 75%. The death of the victim comes swiftly, in 2-3 minutes.

First aid for carbon monoxide poisoning

If you suspect carbon monoxide poisoning, you must immediately evacuate the victim from the CO impact zone, call the ambulance crew, and provide first aid while waiting for her arrival.

  1. Provide fresh air by undoing the embarrassing clothes and open the windows.
  2. If the victim is conscious, give a warming caffeinated drink (tea, coffee) to activate the respiratory and vasomotor centers.
  3. If the victim is unconscious – bring to the nose cotton wool soaked in ammonia, in the absence of an effect, to conduct a vigorous rubbing of the limbs, chest, face to stimulate blood circulation.
  4. If there are signs of clinical death (lack of consciousness, respiration, and pulse in the carotid arteries, dilated pupils that do not respond to light), cardiopulmonary resuscitation should be started immediately.

It is important to remember that when entering the premises where carbon monoxide poisoning allegedly occurred, it is necessary to hold the breath and leave it as soon as possible after the evacuation of the injured.

When is medical treatment required?

In the case of carbon monoxide poisoning, qualified medical assistance is needed in 100% of cases. The treatment is carried out in a hospital, in the intensive care unit and resuscitation.

An antidote (Arizol) is administered to the victim, breathing with oxygen or carbogen is provided, further therapy is aimed at maintaining vital functions, eliminating symptoms and preventing the development of complications.

Possible consequences

After carbon monoxide poisoning, the development of both early (in the first 2 days) and late (from 2 to 40 days) complications is possible.

Early include:

  • swelling of the brain;
  • toxic pulmonary edema;
  • heart rhythm disorders;
  • impaired vision and hearing;
  • neuritis.

Late complications:

  • cognitive decline;
  • amnesia;
  • psychosis;
  • movement disorders, paralysis, paresis;
  • pneumonia;
  • myocardial infarction;
  • myocarditis;
  • acute heart failure.


To prevent carbon monoxide poisoning, you must:

  • use only serviceable gas equipment, ensure its timely preventive maintenance;
  • in houses with stove heating to ensure adequate ventilation, to control the position of the stove valve;
  • do not work with the car in the garage, repair the box with the engine;
  • When working with carbon monoxide, observe safety procedures at the workplace.