Prognostic value of the myeloperoxidase index for early prediction of neurologic outcome in acute carbon monoxide poisoning

OBJECTIVE: Carbon monoxide (CO) activates intravascular neutrophils through platelet-neutrophil aggregates, which cause neutrophil degranulation. This process causes the release of myeloperoxidase (MPO), proteases, and reactive oxygen species. The MPO index (MPXI) is a newly reported inflammatory marker that reflects the MPO level within neutrophils. The MPXI in conditions associated with neutrophil activation depends on the net effect of azurophil degranulation. This study aimed to determine whether the MPXI can predict neurocognitive prognosis 1 month after acute CO poisoning. METHODS: We included patients aged ≥16 years with acute CO poisoning from a cohort at a single tertiary academic hospital in Wonju, Korea, between January 2010 and May 2021. Data from 699 patients were analyzed. The neurocognitive outcome was assessed using Global Deterioration Scale scores and classified as favorable (score, 1–3 points) or poor (score, 4–7 points). The MPXI was determined within 1 hour of arrival to the emergency department. RESULTS: Among the 699 patients, 52 (7.4%) showed poor outcomes. The median MPXI of the patients in the poor outcome group was higher than that of the favorable outcome group (0.85 vs. 0.2, P=0.189). However, a significant difference was not found between the favorable and poor outcome groups, and MPXI was not a significant variable in multivariate logistic regression. CONCLUSION: The MPXI evaluated in the emergency department did not differ based on neurocognitive outcome at 1 month after acute CO poisoning.