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Carbon Monoxide Poisoning

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Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention

Definition

Carbon monoxide poisoning can be a deadly condition. It results from inhaling carbon monoxide gas. Carbon monoxide is produced when gas, wood, charcoal, or other fuel is burned. It often builds up when fuel-burning heating and cooking devices are faulty or not properly vented. A car engine can also produce carbon monoxide, as can cigarette smoking. Carbon monoxide is an odorless, tasteless, and colorless gas. People can inhale it without knowing.

Once the gas is inhaled, it 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.

Carbon Monoxide Binding to Hemoglobin

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Causes

Inhaling carbon monoxide gas causes carbon monoxide poisoning.

People can be exposed to the gas when fuel-burning appliances are broken or are not vented properly. For instance:

  • If a vent pipe has a hole, carbon monoxide can escape into the house.
  • Using a barbecue grill or camp stove indoors can cause a build-up.
  • Running a car engine with the garage door closed will cause a build-up.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Risk factors for carbon monoxide poisoning include:

  • Exposure to carbon monoxide through improperly vented or faulty appliances
  • Age:
    • Fetuses (Maternal cigarette smoking is a major source of exposure.)
    • Infants
    • Older adults
  • Smoking (Waterpipe tobacco smoking may put you at an even higher risk.)
  • Geography: northern states
  • Gender: death rates higher in males
  • Blood, heart, or lung conditions

Symptoms

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

  • Shortness of breath
  • Wheezing
  • Cough
  • Hoarse voice
  • Rapid heart rate
  • Chest pain
  • Nausea or vomiting
  • Headache
  • Numbness and tingling
  • Disturbed vision
  • Loss of appetite
  • Disturbed sleep
  • Dizziness
  • Tiredness
  • Memory loss
  • Reduced sex drive

Diagnosis

The doctor will ask about your symptoms and medical history and perform a physical exam. You will be asked questions about:

  • 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—a test that uses radiation to take a picture of structures inside the chest, used to help determine if pneumonia is present
  • Electrocardiogram—a test that records the heart's activity by measuring electrical currents in the heart muscle

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.

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

Other therapies may include:

  • Ventilator—Patients in a coma or with serious heart or nerve involvement may need a ventilator to help them breathe.
  • Hyperbaric oxygen therapy—Patient is placed in a special chamber in which oxygen is 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 risk 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.
RESOURCES:

United States Consumer Product Safety Commission

http://www.cpsc.gov

United States Environmental Protection Agency

http://www.epa.gov

CANADIAN RESOURCES:

Public Health Agency of Canada

http://www.phac-aspc.gc.ca

References:

Breimer LH, Mikhailidis DP. Could carbon monoxide and bilirubin be friends as well as foes of the body? Scand J Clin Lab Invest. 2010;70(1):1-5.

Carbon monoxide poisoning. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/co. Updated April 2009. Accessed July 13, 2009.

Cecil RL, Goldman L, et al. Cecil Textbook of Medicine. 21st ed. Philadelphia, PA: WB Saunders Company; 2000.

Conn HF, Rakel RE, et al. Conn's Current Therapy 2001. 53rd ed. Philadelphia, PA: WB Saunders Company; 2001.

Ferri F, ed. Ferri’s Clinical Advisor 2010. Philadelphia, PA: Mosby Elsevier; 2009.

Goldman L, Ausiello D, eds Cecil Textbook of Internal Medicine. 23rd ed. Philadelphia, PA: Saunders; 2008.

Harrison TR, Fauci AS. Harrison's Principles of Internal Medicine. 14th ed. New York, NY: The McGraw-Hill Companies; 2000.

An introduction to indoor air quality: carbon monoxide (CO). Environmental Protection Agency website. Available at: http://www.epa.gov/iaq/co.html. Updated April 2009. Accessed July 13, 2009.

Juurlink DN, Buckley NA, et al. Hyperbaric oxygen for carbon monoxide poisoning. Cochrane Database Syst Rev. 2005;(1):CD002041.

Marx J, Hockberger R, et al. Rosen's Emergency Medicine. 7th ed. St. Louis, MO: Mosby; 2009.

Rakel R. Textbook of Family Medicine 2007. 7th ed. Philadelphia, PA: Saunders Elsevier; 2009.

Rakel R, Bope E. Conn's Current Therapy. 60th ed. Philadelphia, PA: Saunders Elsevier; 2009.

Rosen P, Barkin RM, et al. Emergency Medicine: Concepts and Clinical Practice. 4th ed. St. Louis, MO: Mosby-Year Book, Inc.; 1998.

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

World Health Organization (WHO) Study Group on Tobacco Product Regulation. Waterpipe tobacco smoking: health effects, research needs and recommended actions by regulators. World Health Organization website. Available at: http://www.who.int/tobacco/global_interaction/tobreg/Waterpipe%20recommendation_Final.pdf. Published 2005. Accessed August 29, 2011.

Last reviewed October 2012 by Peter Lucas, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.