Abstract: Objective  To explore the influencing factors of 30-day prognosis in patients with acute paraquat poisoning(APP) after blood purification. 
Methods  A total of 79 patients with APP who met the inclusion and exclusion criteria in the First Affiliated Hospital of Xi′an Jiaotong Universityand the Second Affiliated Hospital of Xi′an Jiaotong University were selected. The 30-day prognosis was obtained by telephone interview. They were divided into the death group(n=40) and the survival group(n=39). Age, gender, history of hypertension, history of diabetes, poisoning dose, time from taking poison to seeing a doctor, the ratio of neutrophil to lymphocyte, the ratio of monocyte to lymphocyte, blood urea nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase, prothrombin time, thrombin time, acute physiology and chronic health evaluation Ⅱ(APACHE Ⅱ) were compared between two groups. Binary logistic regression analysis was used to predict the risk factors of death. The area under the receiver operating characteristic(ROC)curve(AUC) was used to analyze the predictive value of the poisoning dose of the death group. Kaplan-Meier survival curve was used to analyze the relationship between poisoning dose and 30-day prognosis. 
Results  The poisoning dose and APACHE Ⅱwere independent risk factors for 30-day prognosis(P＜0.05). The AUC of poisoning dose in the death group for predicting 30-day mortality was 0.882(P＜0.001), and the cutoff value was 40 mL(sensitivity of 72.5%, specificity of 87.18%). The AUC of APACHE Ⅱ in the death group for predicting 30-day mortality was 0.722(P＜0.001), and the cutoff value was 4(sensitivity of 85%, specificity of 87.18%). Kaplan-Meier survival curve showed that there was significant difference between poisoning dose＞ 40 mL group and poisoning dose≤40 mL group with respect to 30-day cumulative survival rate(χ2=48.452，Log-rank P＜0.001). 
Conclusion  The poisoning dose and APACHE Ⅱ can predict the 30-day prognosis of patients with APP. The poisoning dose ≤ 40 mL and APACHE Ⅱ ≤ 4 indicate favorable short-term prognosis. 

Key words: paraquat, prognosis, blood purification