Abstract： Objective To investigate the value of regional cerebral oxygen saturation(rScO2)combined with serum soluble triggering receptor expressed on myeloid cells 2(sTREM-2)in the diagnosis of sepsis-associated encephalopathy(SAE).Methods A total of 197 patients with sepsis admitted to the Intensive Care Unit of Jiamusi Central Hospital,Heilongjiang Province from January 2021 to October 2023 were selected.According to the occurrence of SAE in the hospital,the patients were divided into SAE group(80 cases)and non-SAE group(117 cases).The clinical data,rScO2 and serum sTREM-2 levels were compared between the two groups.Logistic regression method was used to analyze the risk factors of SAE.The receiver operating characteristic curve was used to analyze the diagnostic value of rScO2 combined with serum sTREM-2 for SAE.Results The proportion of septic shock,sequential organ failure assessment(SOFA)score,and blood lactate level in the SAE group were higher than those in the non-SAE group,and the heart rate and respiratory rate were faster than those in the non-SAE group(all P＜0.05).The rScO2 in SAE group was lower than that in non-SAE group[(0.57±0.11)vs(0.67±0.06)],and the serum sTREM-2 level was higher than that in non-SAE group[(25±4)ng/L vs(21±4)ng/L](t=-7.222,7.869,both P＜0.05).Logistic regression analysis showed that septic shock,increased SOFA score,increased heart rate,increased blood lactic acid,and increased sTREM-2 were independent risk factors for SAE,and increased rScO2 was an independent protective factor(all P＜0.05).The receiver operating characteristic curve showed that the Youden index of rScO2,serum sTREM-2 and their combination were 0.454,0.452 and 0.575,respectively,and the combination of the two had the highest diagnostic value.Conclusions Decreased rScO2 and increased serum sTREM-2 level are independently associated with the occurrence of SAE.The combination of rScO2 and serum sTREM-2 level has a high diagnostic value for SAE.