Chapter 222: Carbon Monoxide

INTRODUCTION

Carbon monoxide is one of the most common toxic exposures that emergency physicians will encounter. It is the most common cause of fatal poisoning, via either intentional (suicidal) or accidental exposure in the United States, and may be the most common worldwide cause of fatal poisoning.¹ Despite much clinical experience and several randomized trials, there is a great deal of controversy about the ideal approach for management.

EPIDEMIOLOGY

Exact statistics for carbon monoxide poisoning are difficult to determine, mainly due to incomplete reporting. Data from the American Association of Poison Control Centers Toxic Exposure Surveillance System in 2012² reported 13,038 exposures, with 54 deaths. However, this information is limited, as many exposures and some deaths are not reported to the local poison control center. It is also unclear how often patients with mild carbon monoxide poisoning are misdiagnosed and thus are not included in the database. Data from the Centers for Disease Control and Prevention paint a much broader picture of exposures than the Toxic Exposure Surveillance System database. The most recent large epidemiologic report from the Centers for Disease Control and Prevention on the subject, which reviewed data on non–fire-related carbon monoxide exposures, revealed 5149 deaths, for an average of 430 deaths per year.³ Interestingly, the incidence of carbon monoxide exposure has not decreased despite more widespread use of carbon monoxide detectors.³

In the past, vehicular emissions were the major source of carbon monoxide poisoning in adults. Currently, nonvehicular sources have become more common as use of catalytic converters has reduced carbon monoxide in vehicular exhaust emissions⁴ (Table 222-1)

Peak incidence occurs in the fall and winter months, generally due to increased use of space heaters, wood-burning stoves, charcoal burning for heat, or portable generators without adequate ventilation.³ Additional sources of carbon monoxide exposure include air conditioners, portable generators in camping tents, exhaust on motorboats, and Zamboni machines used in ice rinks.^5,6,7 Exposures have been reported in persons riding in the back of pickup trucks, as well as in vehicles with an exhaust pipe occluded by snow.

It is believed that carbon monoxide poisoning is probably the most pressing danger from smoke inhalation and is a major contributor to fire-related deaths. Although carbon monoxide poisoning most commonly affects adults in the third to fifth decades, it may be seen across age groups, and it is not uncommon for entire families to be affected.

Another source for carbon monoxide poisoning is methylene chloride, which is found in varnishes and paint ...