Tto report complications associated with endotracheal intubation (ETI) performed in the Emergency Department (ED) and to isolated predict factor of immediate life-threatening complications. Design: observational study. Setting: The Emergency center of Bach Mai hospital Patients: We evaluated 134 patients. Interventions: From October 1, 2021 to July 30, 2022, data related to all ETI performed in ED were collected. Information regarding patient descriptors, procedures, and immediate complication were analyzed. Measurements and Main. Results: At least one complication occurred in 52 ETIs (38,8%): severe hypoxemia (2,2%), hemodynamic collapse (27,8%), and cardiac arrest (4,5%). The other complications were pneumothorax (1,5%) and aspiration (0,7%), trauma (2,2%). Age >65; Comack lehan 3-4 were identified as independent risk factors for occurrence of complications, and ETI performed by a junior physician supervised by a senior (i.e., two operators) was identified as a protective factor for the occurrence of complications. SI>=0,8 was identified as independent risk facors for postintubation hypotension. Conclusions: ETI in critical patients is associated with a high rate of immediate and severe life-threatening complications.