ENO2 and Coma: However, so far, only a few studies evaluated the correlation between serum NSE levels and consciousness impairment after carbon monoxide (CO) exposure, reporting inconsistent results.[4] S100B protein is associated with glial cell activation and DEACMP occurrence in patients with ACOP.[5]Also, some studies have evaluated the S100B level as an indicator of the severity of CNS affection in patients with ACOP.[6,7] However, early prediction of coma duration in patients with ACOP remains unclear.