Carbon monoxide poisoning

Carbon monoxide is a colorless, odorless gas. It's produced whenever carbon-based fuels such as gas, oil, kerosene, wood or charcoal are burned. If appliances such as gas stoves, heaters, furnaces, woodstoves or water heaters aren't properly vented or maintained, carbon monoxide gas can build up to dangerous levels.

Carbon monoxide is lighter than air and can quickly spread through an entire home or building. Since you can't see or smell carbon monoxide, you can be totally unaware of even the most lethal carbon monoxide levels. In the United States, carbon monoxide poisoning accounts for more than 500 deaths each year. Pets are also at risk.


Causes/associated factors
Hemoglobin (a protein in the red blood cells that contains iron) carries oxygen through the blood to your tissues. Carbon monoxide is 240 times more likely to bind with hemoglobin than oxygen. When you inhale carbon monoxide, it quickly replaces and deprives your body tissues of vital oxygen.
Sources of carbon monoxide may include:

boat motors
cars
charcoal grills
cigarettes
fireplaces (gas and wood) and wood-burning stoves
gas ranges, ovens, dryers, water heaters, grills, furnaces and space heaters
kerosene space heaters
oil furnaces
solid alcohol (such as Sterno Canned Heat)

Signs/symptoms
Carbon monoxide poisoning may have many symptoms, including:
shortness of breath
mild to severe nausea
mild to severe headaches
dizziness
flu-like symptoms
visual disturbances
heart palpitations or chest pain
impaired judgment or confusion
lethargy or fatigue
seizure
intermittent unconsciousness
coma
Some symptoms may not appear immediately. For example, short-term memory loss, fatigue, confusion, and mood or behavior disturbances may occur two to four weeks after exposure to carbon monoxide.


Diagnosis
The doctor will ask questions about your medical history and do a physical exam. A blood test called carboxyhemoglobin can be used to determine if you've recently been exposed to carbon monoxide, as well as the extent of a current or chronic exposure. (This test isn't helpful in diagnosing an isolated past exposure to carbon monoxide.)
To help evaluate the extent and possible effects of exposure to carbon monoxide, your doctor may also suggest one or more of the following tests:

chest X-ray
electrocardiogram (a recording of the electrical activity of the heart)
urinalysis
additional blood work (including arterial blood evaluation, complete blood counts and electrolytes)
computed tomography (CT scan, a computer-generated, cross-sectional picture of internal body parts)
cognitive testing (a neuropsychological evaluation)

Treatment
First, get away from the carbon monoxide fumes and avoid any activities that will increase your need for oxygen. Then, oxygen therapy is the standard treatment. You may be given 100 percent oxygen to breathe through a mask or breathing tube.
Depending on your symptoms and the findings of the physical exam, you may need hyperbaric oxygen therapy. With this treatment, you're placed in a cylinder-shaped chamber that provides 100 percent oxygen at two to three times the atmospheric pressure at sea level. This therapy increases the amount of oxygen that's dissolved in the blood, which increases the amount of oxygen available for use by your body. Hyperbaric treatment also speeds the unbinding of carbon monoxide from hemoglobin.

Additional treatment may be recommended depending on the degree of exposure and your general health. In severe cases, hospitalization may be needed.


Complications
Prolonged exposure to carbon monoxide may lead to complications such as memory problems, organ damage and unconsciousness. In severe cases, carbon monoxide poisoning can be fatal. Those at particular risk of carbon monoxide complications include:
pregnant women and their developing babies
infants
elderly adults
people who have blood problems, such as anemia (a condition marked by a decreased number of red blood cells or hemoglobin)
people who have circulation problems, such as heart disease
people who have respiratory diseases, such as emphysema (a progressive disease that damages the lung's air sacs)
people who have multiple injuries, burns, smoke inhalation or drug intoxication
people who smoke
family pets

Emergency procedures
If your carbon monoxide detector goes off, make sure it's not your smoke alarm. Don't ignore the alarm. In cases of potential carbon monoxide poisoning, call 911 or your local emergency services provider. Open the windows to ventilate your home with fresh air, turn off all possible sources of carbon monoxide, and move people and pets outdoors. If anyone has symptoms of carbon monoxide poisoning, get them into fresh air immediately and seek medical attention promptly.
Emergency service personnel will determine whether it's safe for you to return to or remain in your home. You may be advised to call a technician to evaluate your fuel-burning appliances before turning anything back on. Stay with loved ones, friends or neighbors until safety in your home is ensured.


Pregnancy-specific information
Carbon monoxide poisoning increases the risk of miscarriage, premature labor and fetal death. A baby's hemoglobin binds more readily with carbon monoxide than an adult's, which increases the risks associated with carbon monoxide exposure.

Senior-specific information
The harmful effects of carbon monoxide poisoning increase older adults who have circulatory and respiratory problems. Severe carbon monoxide poisoning is more likely to be fatal for those older than age 75.

Prevention
To prevent carbon monoxide poisoning:
Avoid cigarette smoke.

Don't walk or jog near streets with heavy traffic.

Install carbon monoxide detectors near the bedrooms in your home. (The hallway is often a good spot.) Make sure you buy detectors that meet the most recent requirements of the Underwriters Laboratories (UL) 2034 standard or International Approval Services 6-96 standard.
Also consider the specific tips listed below.

Inside your home
Beware of the following warning signs:

decreased hot water supply
furnace that's unable to keep your house warm or one that runs constantly
loose or missing furnace panel
loose or disconnected vent or chimney connections
loose masonry or chimney
moisture inside the windows
rust, black or water streaks on a vent or chimney
soot buildup in the chimney, furnace or other appliances
Appliance and fuel safety


Have fuel-burning appliances inspected annually, including the vent pipes on heating systems. Also check appliances for adequate ventilation.

Keep flues and chimneys clean and unblocked.

Choose appliances that vent fumes outside.

Don't use a gas oven to heat your home.

Don't operate gas-burning engines such as generators in confined areas (even with ventilation). This includes basements and garages.

Have a qualified professional install any fuel-burning equipment.

If you must use an unventilated gas or kerosene space heater, follow the manufacturer's instructions carefully.

Don't sleep in a room with a gas or kerosene space heater.

New portable, indoor heaters for campers are now available with sensors that shut off if oxygen levels drop. Follow the manufacturer's directions, and turn off heater before going to sleep.

Don't burn charcoal inside any dwelling, including vehicles and tents.

Don't use products containing methylene chloride (such as degreasers, solvents or paint removers) in enclosed or unventilated areas. Inhaling the fumes can cause carbon monoxide poisoning.
Vehicle safety


Remove snow from around the vehicle's exhaust pipe before starting the car. Have passengers wait outside the vehicle while you're removing the snow.

Don't idle your vehicle in the garage -- even with the garage door open. Fumes can build up quickly in the house or garage.

Don't ride in the back of an enclosed pickup truck. Children are especially at risk to the fumes that may build up there.
Houseboat safety


Install a carbon monoxide detector inside the houseboat.

Houseboats with on-board electricity generators that vent toward the rear of the boat can cause carbon monoxide poisoning for people on the rear swim deck or water platform. Avoid these areas while you're swimming or doing other activities.