The Shadow
Dear Fellow Community Members,
I am writing to clarify the misinformation that was put forth by the Shadow in the February 18th edition. It is entirely correct when the Va Department of Health said any elevated Carbon Monoxide (CO) levels drawn on blood on or after February 3rd could not be attributed to the possible January 31 st event.
Science tells us that drugs and toxins have a ½ life – which is basically how long it takes for a substance to be reduced to ½ its level. This principle is commonly used to help tell how often a medication should be dosed or how long a toxin may stay in your system. A drug or toxin is eliminated from your body in 5 and ½ half-lives. The ½ life for CO is 4-6 hours so therefore by 22-33 hours the gas is eliminated or would be at normal levels. To illustrate: if the person after their carbon monoxide exposure had a level of 20 it would fall to 10 in 5 hours; a level of 5 in 10 hours, a level of 2.5 in 15 hours and a level of 1.25 in 20 hours (normal range) if the person is breathing room air (which is 21% oxygen). Administration of 100%
oxygen shortens the ½ life to 1.5 hours. Hyperbaric oxygen shortens it to 30 min. In the case of CO poisoning, clearance of CO starts as soon as the victim is removed from the source of the exposure.
Clearance of CO is almost entirely through the lungs; oxygen is no longer competing with carbon monoxide to bind to hemoglobin and therefore replaces the CO molecules on the binding sites.
Hemoglobin carries the oxygen from your lungs to the peripheral organs/tissues. There are many possible sources for a given individual to have an elevated level or to have a slighter higher level than someone else. There is some variation in baseline levels. This can be due to variable
levels of exposure to fumes, cigarette smoke, outside pollution, intrinsic production, gas stoves, etc.
Clinically significant elevation is if the level is above 3. Also, CO cannot be passed from one person to another.
Thus, science (not just a guess) tells us it is not possible for exposure 3 days prior to testing to result in an abnormal level 3 days later. We need to let science guide our approach to medical issues and not promote disinformation.
Michele Ballou, MD
(Retired
pulmonologist)
