Risk factors and Outcome Analysis of Delayed Neurological Sequelae in elderly patients with carbon monoxide poisoning

Carbon monoxide (CO) poisoning is one of the common causes of poisoning and can result in significant neurological sequelae. However, few studies have focused on the elderly population. We retrospectively reviewed elderly (age≥65 years) with CO poisoning from non-fire accidents and non-suicide at the 6th Medical Center PLA General Hospital in China from 2013 to 2023. A total of 167 patients were enrolled. The annual case number decreased from 2013 to 2023, particularly during the cold months (November to February). The most common source of exposure was coal heating (90%). The most common presenting symptoms were changes in consciousness (90%). Eighty-eight patients (52%) developed delayed neurological sequelae (DNS), of which sixty-nine (78%) converted to long-term neurological sequelae (LNS). The most common imaging manifestations were hypoxic-ischemic damage in the basal ganglia (54%) and demyelination in white matter (46%). After multivariate analysis, initial GCS score and coma time (GCS scores<8) were the independent risk factors for patients with DNS (p<0.001). Interestingly, myocardial injury was more common in non-DNS elderly patients than in DNS patients (p<0.001); only coma time was an independent risk factor for patients with LNS (p<0.001). There was no significant difference between HBO₂ (p=0.19) and NBO (p=0.38) in the occurrence of DNS and LNS in elderly patients with CO poisoning. Therefore, initial GCS score and coma time (GCS scores<8) may be the risk factors of DNS, and coma time may be a high-risk factor for poor prognosis in elderly patients with CO poisoning. Moreover, HBO₂ treatment did not show benefit or harm to those patients. Special attention should be given, and follow-up should be performed on elderly patients, particularly those who have longer coma time and CO exposure time and lower initial GCS scores in acute CO poisoning.