Carbon Monoxide Poisioning

Health and Healthcare CategoryEvery year around this time there’s a news article about people dying from carbon monoxide poisoning, either from a faulty furnace or from sitting in a running vehicle with poor ventilation. A colorless, odorless, tasteless gas, carbon monoxide can build up to dangerous levels insidiously. Carbon monoxide is produced by the combustion of hydrocarbons, so is a frequent byproduct of the combustion of gasoline, kerosene, and oil. As you might expect, carbon monoxide levels are higher in urban and industrialized areas.

BloodBut how exactly does carbon monoxide cause problems? In humans, oxygen is transported to the body by attaching to hemoglobin, a protein found in red blood cells. Carbon monoxide binds to hemoglobin more easily than oxygen, and therefore displaces the oxygen from the red blood cells. In addition, carbon monoxide makes it more difficult for any other oxygen molecules the red blood cell may be carrying to get delivered to the rest of the body. In short, carbon monoxide poisoning mimics oxygen deprivation. There is, however, a condition due to carbon monoxide poisoning known as delayed neurologic sequelae which can’t be explained by poor oxygen delivery, and may have more to do with enzymatic changes in the brain induced by the carbon monoxide molecule. Carbon monoxide can also cause damage to the heart and can cause accumulation of fluid in the lungs, a condition known as pulmonary edema.

Symptoms of carbon monoxide poisoning can be vague and nonspecific. Frequently patients will present with confusion or symptoms directly attributable to oxygen deprivation, such as chest pain. Headaches, nausea and vomiting may also occur.

The diagnosis of carbon monoxide poisoning is largely based on a suggestive history or clear evidence of exposure in addition to elevated levels of hemoglobin bound to carbon monoxide, otherwise known as carboxyhemoglobin. In cases of chronic carbon monoxide poisoning, however, carboxyhemoglobin levels can be inaccurate, making the diagnosis in such circumstances quite difficult.

Treatment of carbon monoxide poisoning is premised on getting enough oxygen into the patient’s system to wrestle the carbon monoxide off of the hemoglobin. This is accomplished with delivery of 100% oxygen into the patient’s lungs via a face mask, or in more severe cases, via a breathing tube connected to a respirator. Hyperbaric chambers can deliver 100% oxygen at high pressures, making delivery of oxygen into the patient’s system even more effective.

Carbon monoxide poisoning is entirely preventable with the use of inexpensive detectors that can be installed in your home. And if you already have carbon monoxide detectors in your home, be sure to check the batteries.

T. A. McNamee, MD

T. A. McNamee, MD, is an associate professor and internal medicine residency program director at Sanford School of Medicine of the University of South Dakota.
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