Feasibility of End-tidal Oxygen Concentration Monitoring During Preoxygenation for Intubation in the Intensive Care Unit.

"A double monitoring of EtO2 will be performed during the procedure of intubation (from the beginning of the preoxygenation to the success of intubation):~* In the pharynx (via a nasopharyngeal catheter) for the needs of the study~* On the facemask (as the practice in the OR)"