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Carbon Monoxide Poisoning

Last updated Aug. 9, 2018

Approved by: Maulik P. Purohit MD MPH

Carbon monoxide (CO) is a colorless, odorless, tasteless, and poisonous gas. Breathing in carbon monoxide is poisonous and can often be fatal. The illness caused by breathing carbon monoxide is termed as Carbon Monoxide Poisoning.


What are the other Names for this Condition? (Also known as/Synonyms)

  • Carbon Monoxide Gas Poisoning
  • CO Gas Poisoning
  • Leaky Furnace causing Carbon Monoxide Poisoning

What is Carbon Monoxide Poisoning? (Definition/Background Information)

  • Carbon monoxide (CO) is a colorless, odorless, tasteless, and poisonous gas. Breathing in carbon monoxide is poisonous and can often be fatal. The illness caused by breathing carbon monoxide is termed as Carbon Monoxide Poisoning
  • When an individual is exposed to too much carbon monoxide, it will destroy his/her oxygen absorbing capacity and cause serious damage to the tissues (due to a lack of oxygen). Young children are more at risk of poisoning than adults
  • Carbon monoxide is produced by devices that produce combustion fumes such as those that burn gas and petroleum products, including internal combustion engines
  • CO can form where there is a partial or incomplete combustion of fuels (such as wood, kerosene, natural gas, and charcoal). When excess carbon monoxide gets accumulated in a poorly-ventilated space, the risk of Carbon Monoxide Poisoning increases
  • The common signs and symptoms exhibited by individuals suffering from CO Gas Poisoning include headache, dizziness, nausea, vomiting, breathlessness, and confusion
  • The condition is treated with pure oxygen. The prognosis for Carbon Monoxide Poisoning varies depending on the level of exposure to CO gas. It is very difficult to forecast the outcome
  • When the gas poisoning is severe, death may occur. But, in most cases, the affected individuals are able to recover and return to a normal life with timely treatment

Who gets Carbon Monoxide Poisoning? (Age and Sex Distribution)

  • Any individual exposed to carbon monoxide is likely to be affected
  • Young children are more at risk of poisoning than adults
  • There is no gender, racial, or ethnic predilection

What are the Risk Factors for Carbon Monoxide Poisoning? (Predisposing Factors)

Risk factors of Carbon Monoxide Poisoning include:

  • Unborn babies: The blood cells of the fetus can absorb carbon monoxide more easily than adult blood cells, meaning that unborn babies are more susceptible to CO Poisoning
  • Children: Young children inhale and exhale at a faster rate than adults, which may increase the risk
  • Winter months: Carbon Monoxide Gas Poisoning tends to occur more in the winter months when the usage of gas furnaces, gas, or kerosene space heaters are increased

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Carbon Monoxide Poisoning? (Etiology)

  • The medical illness that occurs when combustion fumes containing carbon monoxide are inhaled is called Carbon Monoxide (CO) Poisoning
  • When excess carbon monoxide gets accumulated in the air, the oxygen in the hemoglobin of the red blood cells gets replaced with the CO gas
  • This implies that the body tissues and organs are devoid of oxygen that is necessary for life sustenance. This leads to a fatal condition termed as Carbon Monoxide Poisoning
  • Inhalation of smoke caused by fire can also cause CO Poisoning

What are the Signs and Symptoms of Carbon Monoxide Poisoning?

The common signs and symptoms of individuals with Carbon Monoxide Poisoning include:

  • Headache
  • Fatigue and loss of energy
  • Dizziness, confusion
  • Nausea, vomiting
  • Breathlessness
  • Unclear and blurred vision
  • Unconsciousness

How is Carbon Monoxide Poisoning Diagnosed?

A diagnosis of Carbon Monoxide Poisoning may include:

  • Complete evaluation of medical history along with a thorough physical exam. Any incidence of CO Gas Poisoning may have to be explained in detail
  • Diagnostic tests usually performed include:
    • Blood test to check for the level of carbon monoxide
    • Determining the level of carbon monoxide in blood is done by measuring the quantity of carboxyhemoglobin (the result of CO mixing with hemoglobin), as compared to hemoglobin in blood

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Carbon Monoxide Poisoning?

Carbon Monoxide Gas Poisoning can lead to various complications such as:

  • Permanent brain damage leading to:
    • Severe memory loss
    • Problems affecting the thought process
    • Neurological problems
    • Psychiatric problems
  • Damage of the heart leading to cardiac abnormalities

Severe poisoning from carbon monoxide can result in fatalities.

How is Carbon Monoxide Poisoning Treated?

The treatment for Carbon Monoxide Poisoning may include:

Breathing pure oxygen:

  • In the hospital, pure oxygen will be supplied through a mask placed over the nose and mouth
  • This will supply oxygen to the tissues and organs that were devoid of oxygen

Oxygen therapy:

  • The patient is asked to spend time in a pressurized oxygen chamber. Inside the chamber, air pressure is maintained at twice the atmospheric pressure
  • This helps in the speedy replacement of carbon monoxide with oxygen in the blood

How can Carbon Monoxide Poisoning be Prevented?

Observing certain basic precautionary measures can help in the prevention of Carbon Monoxide Poisoning. These measures may include:

  • Installation of carbon monoxide detectors: This will help to detect any leakages. In case of a leakage, the alarm bells will sound
  • Opening the garage door before starting a car: The car should never be started in a closed garage
  • Using gas appliances, as per instructions, will help prevent any adversities such as gas poisoning
  • The proper maintenance of gas appliances and fireplaces is a very important step in the effort towards prevention of Carbon Monoxide Poisoning

It has to be noted that the carbon monoxide gas is a colorless and odorless gas. Individuals who are exposed to the gas may themselves be completely unaware that an exposure to a poisonous gas is taking place.

What is the Prognosis of Carbon Monoxide Poisoning? (Outcomes/Resolutions)

The prognosis for Carbon Monoxide Poisoning is very difficult to forecast.

  • When inhalation of the CO gas is severe, it can result in death
  • In rare cases, even with proper treatment, long-term complications may occur
  • Generally, if the poisoning is mild and for short duration, individuals can recover easily and completely

Additional and Relevant Useful Information for Carbon Monoxide Poisoning:

  • The United States Consumer Product Safety Commission has made it mandatory for all houses to have at least one carbon monoxide detector
  • The US National Fire Protection Association makes it mandatory to place carbon monoxide detectors and alarms at each level of the building
  • Gas organizations often recommend the servicing of the detectors at least once a year

What are some Useful Resources for Additional Information?


References and Information Sources used for the Article:


Helpful Peer-Reviewed Medical Articles:


Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: May 28, 2015
Last updated: Aug. 9, 2018