Carbon Monoxide is Not Well Understood

Misconceptions

Properties, Presence & Detection:

• CO is easy to detect.
• CO is lighter than air and therefore rises (to the ceiling) and stays there.
• CO is not combustible.
• CO and natural gas are the same thing.
• You can always tell if CO is present because of a peculiar odor that will be present.
• A brand new, well designed, perfectly "tuned" heating/cooking device cannot produce toxic/lethal amounts of CO.
• Diesel engine exhaust never contains adequate CO to cause harm.
• HVAC and gas company personnel always check for CO when performing maintenance/service on home heating systems.
• CO will be detected immediately by service personnel if it is present in a home heating system.
• When your home CO detector shows low levels of CO, it is probably just an instrument malfunction.
• Cracks in heat exchangers are responsible for production of CO.
• Home CO detectors/sensors are the best devices to ferret out CO because they react to very low levels of the gas.

More Misconceptions

Physiology

• CO binding to hemoglobin is irreversible.
• CO (caused) hypoxia is no more serious than any other type of hypoxia.
• CO poisoning is no more serious than an anemia in which there is a comparable amount of hemoglobin able to carry oxygen.
• Small animals (birds, mice, etc.) die more quickly because their hemoglobin binds CO more avidly than that of humans, thus they were used as alarms for CO in mines.
• The fetus is protected from CO by the maternal body.
• Good COHb measurements can be obtained one day to a week after a person leaves the site of the CO poisoning.
• Breathing "clean" air for 2-3 hours will eliminate all CO from the body.
• Breathing 100% oxygen for 20-30 minutes will eliminate all CO from the body.
• Breathing (filter) masks protect the wearer from inhalation of CO.

More Misconceptions

Symptoms

• The skin, nail beds, etc. of people with CO poisoning are invariably red or pink in color.
• Fever is a symptom of CO poisoning.
• Nasal congestion, cough and hoarseness are symptoms of CO.
• The lungs are inflammed by low to moderate levels of CO and will show pathology on X-rays.
• Symptom clusters involving prolonged headache, dizziness, nausea, and fatigue of the whole family should be blamed on viruses, bad food, or group craziness.
• Everyone responds to CO in the same way, ie. show the same symptoms.

Even More Misconceptions

Treatment, Outcome

• Inhalation of 100% oxygen from a rebreathing mask or from nasal prongs are recommended best immediate means of removing CO from the body.
• Victims of CO poisoning should be released from medical care immediately following 1-2 hours of oxygen treatment, whether or not their symptoms have disappeared.
• There is no need for repeat COHb measurements, psychometric tests, or other clinical tests following medical treatment for CO poisoning.
• People who recover from CO poisoning are always completely normal.
• Depression and personality change never result from CO poisoning.
• CO exposure never produces brain damage unless there is a period of unconsciousness.
• Low / moderate CO exposure cannot produce brain damage or significant changes in functional performance.
• In environments containing CO, the levels of CO₂, oxygen and other gases are unimportant in the degree of poisoning. 

Miscellaneous

• Physicians receive adequate training in the diagnosis and treatment of CO poisoning in medical school.
• Physicians obtain adequate experience with CO poisoning in treating their patients.
• Psychiatrists and neurologists are the best medical professionals of choice to determine the extent of CNS damage caused by CO.
• High-tech imaging devices (CT, MR, SPECT) always shows areas of brain damage from CO poisoning, if it exists.

Used with permission from the author

David G. Penney, PH.D.