Carbon Monoxide: The “Invisible Killer”

Odorless, colorless and produced by common household appliances that burn fuel, carbon monoxide (CO) can be dangerous when not properly ventilated or used incorrectly. CO exposure is responsible for an estimated 15,000 emergency department visits and 500 unintentional deaths each year. In two groundbreaking studies, Rhode Island Hospital has demonstrated that CO can cause heart damage separate from the effects of oxygen deprivation, and that routine screenings of emergency room patients is a simple yet life-saving practice.

Published in the January issue of Academic Emergency Medicine, one of the hospital’s studies is the first to show that CO causes direct damage to the heart muscle that is unrelated to oxygen deprivation in the recovery phase, even when all CO is out of the system.

“These findings suggest that heart damage caused by carbon monoxide may have long-lasting effects even after its been eliminated from the blood, making the diagnosis of carbon monoxide poisoning even more critical,” says Selim Suner, MD, director of emergency preparedness and disaster medicine at Rhode Island Hospital.

CO poisoning can be very difficult to diagnose, since its symptoms resemble those of the flu and other common illnesses. Pregnant women, children and the elderly are most susceptible to CO poisoning.

In an effort to improve CO diagnosis rates, Suner and his team conducted a second study, the largest of its kind, in which more than 14,000 patients visiting the hospital’s emergency department were routinely screened for CO exposure during a three month span. Published online by The Journal of Emergency Medicine, researchers found a total of 28 cases of CO poisoning, 11 of which were unexpected and identified only with routine screening. None of the 11 patients exhibited the usual signs of CO poisoning. Nearly a third of the patients required hyperbaric oxygen treatment, in which 100 percent oxygen is delivered under high pressure in a specialized chamber to reduce the amount of CO in the blood and return oxygen levels to normal.

“There is a clear and significant benefit to universal screening for carbon monoxide, especially during the winter months, when carbon monoxide poisoning is most common,” says Suner. “Unless you have a carbon monoxide detector, it’s extremely difficult to know if you’re being exposed to toxic levels of this gas. If we can identify these cases of unsuspected poisoning early on, we can administer treatment and prevent them and others from being further exposed.

“We demonstrated that its possible to conduct quick, non-invasive and inexpensive carbon monoxide screening on every patient even in a high volume, urban emergency department. This is a public health initiative that could be applied universally in other large health care institutions.”

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