Definition

Carbon monoxide is an odorless, tasteless, and colorless gas that is found in combustion fumes. Inhaling too much carbon monoxide results in poisoning, which can be fatal.

Causes

Carbon monoxide is easily absorbed through the lungs. Hemoglobin carries oxygen in the blood to the entire body. Carbon monoxide binds tightly with hemoglobin and takes the place of the oxygen. Tissue then becomes starved for oxygen. Brain tissue is very much at risk.

Faulty or improperly vented equipment causes a build up of carbon monoxide in semi- or enclosed spaces. Exposure can be the result of:

• Motor vehicle engines that are left running inside an enclosed garage
• Any heating and cooking devices that burn coal, wood, or gas
• Barbecue grills, gas grills, or camp stoves used inside your home, garage, or basement
• Gas oven ranges used to heat your home when the power goes out
• Power generators used inside your home, garage, or basement

Risk Factors

Carbon monoxide poisoning is more common in infants or older people. Other factors that may increase your risk of carbon monoxide poisoning include:

• Living in a cold external environment
• Having a heart or lung condition
• Smoking

Symptoms

Symptoms related to carbon monoxide poisoning are usually vague. They can be split into acute and chronic symptoms.

Diagnosis

The doctor will ask about your symptoms and medical history. A physical exam will be done. Questions may include:

• Whether symptoms come and go
• If anyone else in the household feels ill
• If you use fuel-burning appliances

Tests may include:

• Blood tests—to measure oxygen level and electrolytes
• Carboxyhemoglobin test—to help determine the severity of exposure and monitor treatment
• Chest x-ray —to determine if pneumonia is present
• Electrocardiogram (EKG)—to check the heart’s electrical activity and look for signs of heart damage

Treatment

Move away from the source of the carbon monoxide. Breathe fresh air outdoors. Mild symptoms usually start to resolve after getting away from the gas.

Always seek medical care at the closest emergency room. Explain that you think you may have been exposed to carbon monoxide. The doctor will give you oxygen until your symptoms go away and carbon monoxide levels in your blood drop.

Other therapies may include:

• Ventilator—to assist in breathing for people in a coma, or who have serious heart or nerve involvement
• Hyperbaric oxygen therapy —a special chamber in which oxygen is given under greater pressure than normal

Prevention

Avoiding exposure to carbon monoxide is the key to preventing carbon monoxide poisoning. Since the gas has no odor or color, you will not know if it is present. The following suggestions can reduce your chance of exposure:

• Have an expert check your fireplace chimney every year. Debris can block vents, causing a build-up of carbon monoxide.
• Before the start of the heating season, have a professional check that your gas and kerosene appliances are working properly.
• Make sure all gas and combustion appliances are vented to the outdoors through pipes with no holes.
• Do not use your gas stove or oven for heating your house.
• Do not use a barbecue grill, camp stove, or unvented kerosene heater inside your house or tent.
• Do not use generators or other gasoline-powered engines indoors.
• Only buy and use equipment that carries the seal of the American Gas Association or the Underwriters’ Laboratory.
• Do not rely exclusively on a carbon monoxide detector. Use one only as backup, in addition to preventive measures. Follow manufacturer’s directions for installation and maintenance.
• Ask a mechanic to check your car’s exhaust system every year.
• Do not run the car in the garage, especially with the door closed. Start the car and take it outside.
• Do not leave the door from the garage to the house open when the car engine is running.

US Environmental Protection Agency http://www.epa.gov

Public Health Agency of Canada http://www.phac-aspc.gc.ca

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http://www.cdc.gov/co
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Carbon monoxide poisoning. EBSCO DynaMed website. Available at:
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Juurlink DN, Buckley NA, et al. Hyperbaric oxygen for carbon monoxide poisoning. Cochrane Database Syst Rev. 2005;(1):CD002041.

Weaver LK, Hopkins RO, et al. Hyperbaric oxygen for acute carbon monoxide poisoning. N Engl J Med. 2002; 347:1057-1067.

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Accessed December 30, 2013.