Article Text

Download PDFPDF

Low level CO poisoning is a hidden danger to an unsuspecting public

Statistics from

People’s health in the UK is threatened by low level exposure to carbon monoxide (CO) and will continue to be until a simple test is developed to confirm CO poisoning, according to a recent review.

Without a reliable biochemical marker all we will see in individual cases and populations will be “just the tip of the iceberg”. There is already sufficient evidence from population studies, the review’s author believes, for research to determine whether the threshold amount of atmospheric CO currently considered safe is indeed so.

For now, accident and emergency staff have to rely on vigilance in correctly diagnosing chronic CO poisoning—that is, repeated exposure, usually to low amounts of the gas. Occult poisoning—usually by chronic low level exposure—may not be recognised until repeated presentations with the same symptoms. CO poisoning is easily overlooked, because even classic signs and symptoms suggest many other possible diagnoses. Many factors confound the diagnosis, among them endogenous carboxyhaemoglobin (COHB) and COHB from atmospheric pollution and from smoking. COHB itself is poorly related to symptoms, and its accurate measurement is difficult and insufficiently researched.

The epidemiology of CO poisoning is similarly ill defined. Descriptive studies have provided sporadic evidence; population studies are dogged by other confounding environmental influences. Nevertheless, a steady decline in deaths attributed to CO poisoning in the US during 1979–1988 coincided with a 90% drop in CO emissions from cars. In patient group studies CO amounts as low as 4–5% limit work capacity and maximal oxygen consumption in healthy people.


Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.