NEJM -- Heart Disease Deaths among Firefighters

NEJM -- Heart Disease Deaths among Firefighters:

"To the Editor: It is somewhat surprising that the report by Kales and colleagues (March 22 issue)1 on emergency duties and deaths from heart disease among firefighters in the United States does not cite the possible influence of carbon monoxide as a causative factor in deaths due to coronary heart disease among firefighters suppressing a fire. There is no doubt about the role of moderate and severe carbon monoxide intoxication in myocardial injury or long-term mortality of cardiac origin.2 We performed a study that showed that even in the case of mild carbon monoxide intoxication (carboxyhemoglobin level, <25%), 4% of patients have ischemic changes.3 It has been reported that firefighters who are nonsmokers and who do not use self-contained breathing apparatus correctly may have carboxyhemoglobin levels of up to 14%.4 Even when such apparatus are used correctly, the carboxyhemoglobin level can reach 9.1%.5 We suggest that the increase in cardiovascular demand during fire suppression reported by Kales and colleagues may be partially due, on the one hand, to elevated carboxyhemoglobin levels and, on the other hand, to the union of carbon monoxide with mitochondrial cytochrome oxidase, which directly interferes with cellular respiration.2"