Carbon Monoxide Poisoning



Two children traveling in the back of an older model car were found unconscious and not breathing. At first, an adult in the front seat thought that they were sleeping. When they did not respond, the driver sped to a hospital, while the other adult passenger performed rescue breathing. By the time they arrived at the emergency department, one of the children was in cardiac arrest. The child later died, while the companion survived. Both were carbon monoxide (CO) poisoning victims.

Carbon monoxide poisoning is the single largest cause of death by poisoning in the United States. It results from the incomplete combustion of carbon-rich fuels. It can be produced by defective cooking equipment, fires, and charcoal grills. Fires that occur in a closed space environment are subject to incomplete combustion with subsequent carbon monoxide production. The average automobile can produce a near-lethal level of carbon monoxide in a single car garage in less than ten minutes. Even a person in a closed room where there is cigarette smoke can experience mild increases in the level of CO in the blood.

The automobile is probably the most potent producer of CO. People who drive long distances in older and often poorly maintained cars, such as college students on their spring break or migrant farm workers, are at increased risk. Drivers and passengers have been overcome by CO while the vehicles were in motion. Rust is a major factor in damaging the exhaust system and creating holes in the body of the car through which CO can enter the cab. Even a two-year-old car can have significant rust damage.

Many CO poisoning deaths involve persons who are sleeping inside a parked car, often because of alcohol consumption. Falling asleep may be inadvertent and caused by a combination of alcohol and CO. Deaths have also occurred due to parking in remote areas for romantic purposes.

The risk of CO poisoning is greatest in the winter. Due to the cold, people spend more time indoors with tightly closed windows and doors. Furnaces are turned on and kerosene burners are brought out.

In the United States, males account for over seventy percent of all deaths from CO poisoning. While death occurs at all ages, the death rate is very low in childhood and increases with age. However, once exposed to CO, children usually do not fare as well as adults. Also women, because they are usually comparatively anemic, are at greater risk after exposure.

Several factors exacerbate CO poisoning. One is exposure during physical activity. Exercise or hard labor can cause higher levels of CO in the blood quite rapidly during short exposures. Both cardiac output and rate of respiration increase during exercise. This affects the severity of poisoning by influencing the rate of CO uptake and elimination by the body.

CO is an invisible and odorless lighter-than-air gas. Once inhaled, it enters the blood of the victim where it is about 200 times more bondable to the hemoglobin (found in red blood cell). Hemoglobin normally carries oxygen out to the cells of the body. With CO attached, hemoglobin is useless. Tissue death can occur rapidly and lead to fatality.

As the amount of attached CO increases, the victim's level of consciousness descends into irritability, impaired judgment, and confusion. The victim will develop a terrible headache, loss of visual acuity, dizziness, and nausea. It will be increasingly difficult for them to get a full breath. The classic cherry-red skin and lips, often cited signs of CO poisoning, appear at death.

Rescuers should be careful and should move the victim to fresh air. If the victim has been exposed to low concentrations of CO, they will probably recover completely in a few hours. If the concentrations have been high, they may die even after being removed from the source of the gas. CO victims need rapid evacuation to a pressure chamber and high concentrations of supplemental oxygen.

Prevention
Risk of CO poisoning can be lessened by following the guidelines listed below:

1. Keep motor vehicle exhaust systems maintained by regular examination and replacement when needed.
2. Have furnaces serviced by a qualified person once a year.
3. If working indoors with a gasoline-powered vehicle, maintain safe, well-ventilated working conditions.
4. If using a kerosene heater, then be sure to follow the instructions provided by the manufacturer.
5. Keep motor vehicles properly tuned up to reduce the amount of CO produced.
6. Have good circulation around and under the car if running the engine while the car is standing still.