Objective:To evaluate the value of platelet to lymphocyte ratio (PLR) and neutrophil to lymphocyte ratio (NLR) in predicting short-term prognosis of acute severe carbon monoxide poisoning.Methods:Clinical data of 180 patients with acute severe carbon monoxide poisoning admitted to Hanzhong Central Hospital from October 2021 to May 2023 were retrospectively analyzed. According to the prognosis of the patients within 6 months, they were divided into poor prognosis group ( n=37) and good prognosis group ( n=143). The baseline data and laboratory indicators of the two groups were compared, and the risk factors of short-term poor prognosis in acute severe carbon monoxide poisoning patients were analyzed by multivariate logistic regression. The value of neutrophils (NEU), platelets (PLT), lymphocytes (LYM), PLR and NLR in predicting short term poor prognosis in patients with acute severe carbon monoxide poisoning was analyzed by receiver operating characteristic (ROC) curve. Results:The proportion of ≥60 years old, stroke history, exposure time >8 h and the levels of NEU, PLR and NLR in the poor prognosis group were higher than those in the good prognosis group, while the PLT and LYM were lower than those in the good prognosis group (all P<0.05). Multivariate logistic regression analysis confirmed that ≥60 years old, stroke history, exposure time >8 h, PLT, LYM, NEU, PLR, NLR levels were the risk factors for short-term poor prognosis in acute severe carbon monoxide poisoning patients (all P<0.05). According to ROC curve analysis, the areas under ROC curve of PLT, LYM, NEU, PLR and NLR to predict the short-term prognosis of acute severe carbon monoxide poisoning patients were 0.684, 0.702, 0.720, 0.889 and 0.801, respectively. Conclusions:Age, stroke history, exposure time, PLT, LYM, NEU, PLR and NLR levels are all factors affecting the short-term poor prognosis of patients with acute severe carbon monoxide poisoning. Increasing PLR and NLR levels will increase the risk of short-term poor prognosis of patients with acute severe carbon monoxide poisoning.