Exclusion criteria : rapid sequence induction, anticipated difficult mask ventilation (2 or more factors among age > 55 years, body mass index > 26 kg m-2, beard, history of snoring, lack of teeth), anticipated difficult intubation (history of difficult intubation, Mallampati class 3 and 4, thyromental distance < 60 mm, interincisor distance < 35 mm, limited cervical spine movement), and refusal to participate to the study and to sign informed consent.