What is acute CO poisoning

Carbon monoxide poisoning


Gerald F. O'Malley

, DO, Grand Strand Regional Medical Center;

Rika O'Malley

, MD, Albert Einstein Medical Center

Last full review / revision Jul 2020 | Content last changed Jul 2020
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  • Carbon monoxide poisoning is common.

  • Symptoms can include headache, nausea, drowsiness, and confusion.

  • The diagnosis depends on the blood tests.

  • Carbon monoxide meters, proper ventilation of stoves and other sources of poisoning inside a building, and avoiding running a car in an enclosed space (such as an enclosed garage) all help prevent carbon monoxide poisoning.

  • Treatment includes fresh air and high levels of oxygen, sometimes the use of a hyperbaric (high pressure) oxygen chamber.

Carbon monoxide is a colorless and odorless gas that, when inhaled, prevents the blood from transporting oxygen and the tissue from using the oxygen effectively. Small amounts are usually harmless, but if the carbon monoxide level is too high, poisoning occurs. Carbon monoxide is broken down in the blood within a few hours.

Smoke from a fire generally contains carbon monoxide, especially if the fuels are not completely burned. If not properly ventilated, automobiles, smelters, water boilers, gas burners, kerosene heaters, and open-burning stoves and fireplaces (including wood-burning stoves and charcoal briquette stoves) can cause carbon monoxide poisoning. For example, if the exhaust pipe of a running vehicle is blocked by snow or other objects, the levels of monoxide in the vehicle can rise rapidly and be fatal. The carbon monoxide absorbed into the blood when smoking is usually insufficient to cause symptoms of poisoning.

Did you know ...

  • Carbon monoxide is one of the most common causes of death from poisoning.


A slight carbon monoxide poisoning causes headache, nausea, drowsiness, difficulty concentrating, vomiting, dizziness and incoordination. Most people who have mild carbon monoxide poisoning recover quickly when they get outdoors.

A moderate or severe carbon monoxide poisoning causes impaired judgment, confusion, loss of consciousness, convulsions, chest pain, shortness of breath, low blood pressure, and coma. As a result, many victims are unable to move on their own and need to be saved.

A severe carbon monoxide poisoning is often fatal. In rare cases, after tentative recovery from carbon monoxide poisoning, symptoms such as memory loss, incoordination, movement disorders, depression, and psychosis (known as delayed neuropsychiatric symptoms) may develop weeks later.

The dangerous thing about carbon monoxide poisoning is that drowsiness and drowsiness are usually not counted as symptoms of poisoning. Therefore, a person with mild poisoning can go to sleep and continue to breathe carbon monoxide unsuspectingly until severe poisoning or death occurs. Some people with chronic carbon monoxide poisoning from stoves or boilers may attribute their symptoms to other causes, such as the flu or other viral infections.


Carbon monoxide poisoning is diagnosed by measuring the amount of carbon monoxide in the blood.

Because of its vague and varied symptoms, mild monoxide poisoning is often mistaken for a cold. If people from the same home, especially a heated home, have vague cold symptoms, doctors can assume carbon monoxide poisoning is the cause.


As a safety measure, sources of combustion in the home, such as gas heaters and wood stoves, must be properly installed and ventilated. If such ventilation is impractical, an open window can reduce the build-up of carbon monoxide by allowing it to escape the building. Stovepipes for discharging the exhaust gases and other heating devices must be regularly serviced and checked for defects and leaks.

There are chemical detectors for the home that can detect carbon monoxide in the air and sound an alarm if it is present. If a home is suspected of having carbon monoxide, the windows should be opened and the building should be evacuated and the source of the carbon monoxide identified. Constant monitoring with detectors can detect carbon monoxide before poisoning occurs. Carbon monoxide detectors, like smoke alarms, are recommended for all households.

Did you know ...

  • Carbon monoxide detectors, like smoke alarms, are recommended for all households.


  • additional oxygen

  • Possibly hyperbaric oxygen

In the case of slight poisoning, fresh air is sufficient. In the case of severe poisoning, highly concentrated oxygen is given, usually through a breathing mask. Oxygen speeds up the removal of carbon monoxide from the blood and alleviates symptoms. The benefit of oxygen therapy (in a hyperbaric chamber) has not been established. Doctors usually consider such treatment for people with moderate or severe poisoning and for pregnant women, even if the levels of carbon monoxide in the pregnant woman's blood were not high enough.

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