The Wake-up The start of the study period coincides with the suspension of the hypnotics (propofol/sevoflurane or desflurane). At this moment the timing of extubation begins which is at the discretion of the anesthesiologists who would evaluate the patient as usual for extubation criteria (respiratory dynamics, ability to maintain SpO2 >95%, Et CO2 between 30 - 40 mmHg, muscle strength, the presence of laryngeal reflexes, and swallowing, etc.) At that point the anesthesiologist will bring the flow of fresh gas to a value greater than that of the minute ventilation and change the circuit to an open system. The time between the suspension of anesthesia and extubation will be recorded on the patient's anesthetic record.