Carbon monoxide “myths”

December 24, 2015, 4:47 pm


Myth busting in carbon monoxide poisoning. Hampson NB. Am J Emerg Med 2015 Nov 3 [Epub ahead of print]


This short review, by the former medical director for the Virginia Mason Center for Hyperbaric Medicine in Seattle, sets out to debunk four “myths” associated with carbon monoxide (CO) exposure. Although nothing here will surprise most emergency physicians, the paper may be worth a quick look.

The “myths” discussed are:

  1. The caboxyhemoglobin (COHb) level correlates with symptoms in acute CO poisoning: What really matters is CO in the cells and central nervous system, not the blood. The commonly published table giving specific symptoms that occur at different carboxyhemoglobin levels first appeared in a 1922 paper, and has been passed down to review articles and book chapters — unreferenced — ever since.
  2. Without fuel-burning appliances in the home, there is no risk for CO poisoning: This mistaken belief does not account for the permeability of dry wall, leakage from neighboring units or a garage, or CO producers (generators, hibachis etc) the that may be brought indoors. Key point: “CO alarms should be installed in all residences.”
  3. Fresh arterial blood samples are needed for accurate determination of caboxyhemoglobin levels: For clinical purposes, venous COHb levels will do just fine. In addition, these levels are stable in an anti-coagulated unrefrigerated venous blood sample, even if there is a considerable delay before the test is performed.
  4. CO poisoning predisposes to long-term risk for cardiac death: There is no scientific basis for this belief.

One additional editorial point. The references in this paper have been bollixed up, with footnotes rarely indicating the appropriate article. Hopefully this will be corrected before the article appears in print.

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