Clinical Question: Is myocardial injury among patients with carbon monoxide poisoning associated with an increased risk of long-term mortality?

Setting: Inpatient (any location) with outpatient follow-up

Study Design: Cohort (prospective)

Synopsis: Carbon monoxide poisoning is one of the most common types of accidental poisoning. The investigators searched for an association between myocardial injury and long-term mortality in patients following moderate to severe carbon monoxide poisoning. The study population included 230 adults, 18 years or older, who were treated for moderate to severe carbon monoxide poisoning with hyperbaric oxygen in a regional referral center in the midwestern United States. Follow-up occurred for a median of 7.6 years and was completed using the Social Security Death Index.

Myocardial injury was defined as a cardiac troponin I level greater than or equal to 0.7 ng per mL (0.7 μg per L), a creatine kinase-MB level greater than or equal to 5 ng per mL (5 μg per L), or diagnostic electrocardiographic changes. A total of 85 patients (37 percent) met criteria for myocardial injury. Of these, 32 (38 percent) eventually died during the study; only 22 of 145 patients with no evidence of myocardial injury (15 percent) died during the study. In-hospital mortality was 5 percent (12 patients).

Bottom Line: Myocardial injury is a common complication of moderate to severe carbon monoxide poisoning and is associated with a significantly increased risk of long-term mortality. (Level of Evidence: 1b)