Objective predictors of delayed neurological sequelae in patients with altered mental status after carbon monoxide poisoning

Abstract

Background and Purpose: Following carbon monoxide (CO) poisoning, altered mental status is an important predictor of poor neurological prognosis, including delayed neurological sequelae (DNS). However, it is difficult to interview CO-poisoned patients accurately about exposure intervals and loss of consciousness (LOC). Thus, we investigated whether DNS can be predicted using objective factors such as laboratory results and brain imaging in patients suffering CO poisoning with altered mental status. Methods: This was a prospective observational study involving all CO-poisoned patients who visited the university hospital emergency department (ED) in Bucheon, South Korea, between January 2019 and April 2020. All were registered in the CO registry. We excluded patients who were under 18 years of age, had no change in mental status, were lost to follow-up, had neurological deficits persisting at discharge from the ED, and/or were transferred from another hospital 24 hours after exposure. Results: A total of 21 (25.3%) of 82 patients had DNS with a median onset of 21 (12 to 30) days. Creatinine kinase (CK) (odds ratio 1.0002, 95% confidence interval 2.734-105.231) and brain imaging (odds ratio 3.206, 95% confidence interval 1.008-10.199) were independent prognostic factors of DNS. Conclusions: A high level of serum CK and abnormal brain-imaging results were significant predictors of the occurrence of DNS in CO-poisoned patients with altered mental status. Critically, these are objective rather than subjective factors such as CO exposure interval.