Acute Carbon Monoxide Poisoning: Prognostic Factors for Delayed Neuropsychiatric Sequelae

ABSTRACT

PURPOSE: Delayed neuropsychiatric sequelae (DNS), which are thought to arise from delayed post-hypoxic leukoencephalopathy, commonly occur after recovery from acute carbon monoxide (CO) poisoning. This study was conducted in order to determine the prognostic factors for DNS in patients with CO poisoning. METHODS: This prospective study included 200 patients with CO poisoning from January 2009 to December 2013. We compared clinical variables between patients with (n=52) and without DNS (n=148). DNS was considered present when the patient had clinical symptoms and signs of DNS within six weeks after exposure to CO poisoning. RESULTS: DNS occurred at a rate of 26.0%. In univariate analysis, the prognostic factors for DNS were loss of consciousness, duration of unconsciousness, Glasgow coma scale, peripheral neuropathy, hypotension, elevated cardiac enzyme at admission, and magnetic resonance imaging (MRI) findings at admission (p<0.05), however, in multivariate analysis, the only independent prognostic factor for DNS was initial MRI findings (OR=16.977, 95% CI=3.051-94,476). Abnormal MRI findings showed significant association with DNS in both the normobaric oxygen therapy and hyperbaric oxygen therapy groups. In patients with normal MRI findings, peripheral neuropathy could predict DNS. Among MRI abnormalities, lesions in the deep white matter (OR=24.719, p=0.000) and globus pallidus (OR=7.062, p=0.001) showed significant association with DNS. Patients with DNS had good prognosis (activity of daily living of grade 1 and 2) of 86.5% and mortality of 5.8% after six months. CONCLUSION: Initial MRI finding can be used in predicting late sequelae in patients with CO poisoning.