Patients randomized in "HFNC" group will receive a four minutes preoxygenation period with Nasal High Flow Therapy (60 L/mn , fraction of inspired oxygen (FI02) = 100%) before orotracheal intubation under laryngoscopy after crash induction. After induction and during laryngoscopy, HFNC will be maintained in an attempt to achieve apneic oxygenation.