Abstract： Objective:To observe the effects of early energy intake and early enteral nutrition on prognosis of patients during extracorporeal membrane oxygenation (ECMO).Methods:Patients who received ECMO treatment in the emergency intensive care unit (EICU) of the Jiangsu Provincial Hospital (First Affiliated Hospital of Nanjing Medical University) from January 2021 to June 2022 were selected as subjects to summarize the early energy intake of ECMO patients. Logistic regression analysis and restricted cubic spline (RCS) analysis were used to determine the relationship between early energy intake and prognosis of ECMO patients. According to the results of RCS analysis, the patients were divided into energy-deficient group and energy-sufficient group. And according to whether early enteral nutrition (EEN) was initiated, the patients were divided into EEN group and non-EEN group. The differences of clinical outcomes between energy-deficient group and energy-sufficient group, EEN group and non-EEN group were compared.Results:There was no significant difference in age, sex, BMI, primary disease and ECMO pattern between energy-deficient group and energy-sufficient group, EEN group and non-EEN group. The ECMO conversion time (days) and hospitalization time (days) in the energy-deficient group were significantly lower than those in the energy-sufficient group, and the survival rate in the energy-deficient group was significantly lower than that in the energy-sufficient group [43.2% (19/44) vs. 66.0% (31/47), P=0.029]. Kaplan-Meier survival analysis showed that the 28-day survival rate in the energy-deficient group was significantly lower than that in the energy-sufficient group, and the risk of death was 2.595 times higher than that in the energy-sufficient group. The conversion time (days), hospital stay (days) and average daily energy intake [kcal/(kg·d)] in the EEN group were higher than those in the non-EEN group ( P<0.05), and the survival rate in the non-EEN group was significantly higher than that in the non-EEN group [66.1% (41/62) vs. 31.0% (9/29), P<0.002]. Kaplan-Meier survival analysis showed that the 28-day survival rate in the non-EEN group was significantly lower than that in the EEN group, and the risk of death was 2.981 times higher than that in the EEN group ( P<0.001). Conclusions:The energy intake of patients with ECMO above 16.94 kcal/ (kg·d) is a protective factor for prognosis. EEN helps to increase early energy intake and improve prognosis in patients during ECMO.