In case of respiratory distress, patients are intubated to be connected to an artificial respirator to ensure gas exchanges. Before any ventilatory weaning, a breathing test in spontaneous ventilation under artificial nose is practiced. The patient keeps the endotracheal tube but is no longer assisted by the ventilator. Mortality is markedly increased with the prolongation of the weaning period. Despite the presence of all weaning criteria and the success of a breathing test in spontaneous ventilation under artificial nose, failure of extubation occurs in 20% of patients.

Experimental application of an additional inspiratory load in awake healthy subjects causes a compensatory increase in respiratory work to maintain effective ventilation, and the subject does not develop hypoventilation. This respiratory drive to breathe has been demonstrated by quantified electroencephalography in inspiratory load tests in the form of pre-inspiratory negative deflections of low amplitude similar to the potential described during the preparation of the voluntary movement of a limb. These inspiratory pre-motor potentials begin about 2.5 seconds before the start of a movement in the additional motor area.

Does the simple and noninvasive analysis of inspiratory cortical control during the spontaneous ventilation breath test under artificial nose predict the outcome of this test as well as weaning at 7 days?

Inclusion Criteria:

• All intubated-ventilated patients eligible for an artificial nose breathing test in spontaneous ventilation, according to the physician in charge, and to the protocol of the medical resuscitation service and good clinical practice,
• at least 18 years of age;
• intubated-ventilated for at least 24 hours;
• express consent given by patients or "relatives" after clear and fair information on the study.

Exclusion Criteria:

• Patients are secondarily excluded from the study only if EEG or pressure monitoring are uninterpretable.