Carbon monoxide poisoning can have long-term effect

NEW YORK (Reuters Health) - Moderate to severe carbon monoxide (CO) poisoning can cause injury to the heart muscle that increases the long-term risk of death, according to a report in the Journal of the American Medical Association.

Previous reports have shown that in-hospital mortality is low for patients with moderate to severe CO poisoning, but it has been unclear if CO exposure affects long-term mortality risk.

To investigate, Dr. Timothy D. Henry, from Minneapolis Heart Institute Foundation, and colleagues assessed the outcomes of 230 consecutive patients who were treated with hyperbaric oxygen for CO poisoning between 1994 and 2001. The subjects were followed until November 11, 2005.

Damage to the heart, based on measurement of cardiac enzymes or ECG changes, was identified in 37 percent of the patients, the report indicates. During an average follow-up of 7.6 years, 24 percent of the patients died. Twelve of these patients died while hospitalized.

On long-term follow-up, the death rate for patients with heart muscle injury was 38 percent compared with a rate of 15 percent for those without heart damage.

Heart damage often occurs in patients with moderate to severe CO poisoning and these patients have a higher mortality risk, the authors conclude.

They recommend that patients who may have been exposed to CO should be screened for heart damage and additional cardiovascular risk assessment should be considered for all patients with confirmed heart injury.

SOURCE: Journal of the American Medical Association, January 25, 2006.