Carbon monoxide levels in cardiac patients in an urban emergency department.

Arterial carboxyhemoglobin (COHb) levels of patients who presented to an emergency department with cardiopulmonary complaints were determined. The purpose of the study was to see whether COHb levels of these patients indicated an acute risk factor in the severity of exacerbation of their cardiac disease. Factors known or thought to increase COHb levels (smoking and arrival by ambulance, for example) were correlated with COHb levels and final diagnoses of myocardial infarction, exacerbation of stable angina or congestive heart failure, asthma, and chronic obstructive pulmonary disease. Statistically significant increases in COHb were found in patients admitted to the intensive care unit and with proven myocardial infarction over a control group. However, these differences could be accounted for by smoking alone or by instrumental margin of error and were not thought to be related to ambient urban carbon monoxide.