ABSTRACT
Toxicity Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 575 25.7 Case Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 577
25.7.1 Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 577 25.7.2 Case Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585
25.8 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 586 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587
Carbon monoxide (CO) poisoning is a relatively common environmental toxic exposure risk that can masquerade as other illnesses. Attribution to CO toxicity can be made based on clinical findings and knowledge of a malfunctioning heater, without evidence of elevated carboxyhemoglobin (COHb) levels or acute mental status changes. In the United States, CO toxicity is implicated in more than 40,000 emergency department visits made annually.1,2 CO is found wherever there is incomplete combustion of carbonaceous material, and, after carbon dioxide, it is the most
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of CO fires, faulty combustion heating systems, exhaust from internal combustion engines, and heating gases other than natural gas. Auto exhaust and exhaust gases from oil heat were most commonly associated with elevation of COHb in a study of serially admitted children to an urban emergency department who had elevated COHb levels.2 Normal COHb saturation is 0.4-0.7% at rest, while the ambient level is 0.5-1.5% in the general population due to added environmental exposure. Tobacco smokers have COHb levels ranging from 4% to 20%; the mean for one-pack/day smokers is 5-6%. COHb levels may be higher during pregnancy. Infants of mothers who smoke may have COHb elevations up to 4.3%.
