Monitoring of Regional Lung Ventilation by Chest Electrical Impedance in the Course of Extubation

Inclusion Criteria: 1. Age\> 65 years 2. Invasive mechanical ventilation time greater than 48 hours 3. known or suspected Chronic obstructive pulmonary disease 4. Known or suspected heart failure 5. Success in the spontaneous ventilation and extubation test scheduled by the doctor in charge 6. Patient or trusted person who has been informed of the study and has consented to participate Exclusion Criteria: 1. Pregnant women, minor patients 2. Patients under extracorporeal circulatory assistance (ECMO) 3. Refusal of the patient 4. Contraindications to the realization of the phrenic nerve stimulation technique: * Pacemaker, implantable cardiac defibrillator and other pacemakers * Spinal implants, thoracic drains ... * Copper allergy * Epileptic patients 5. Patients performing uncontrolled body movements 6. Contraindications to the realization of the technique of Electrical Imaging Tomography: * Breast circumference not between 70 cm and 150 cm. * Body mass index (BMI) greater than 50 * Impossibility of placing the CT belt at the level of the chest skin (lesions, bandages, dressings, chest drains ...) * Patients with unstable spinal lesions or fractures * Allergy to tomography belt materials: silicone, brass, stainless steel * Pacemaker, implantable cardiac defibrillator and other pacemakers 7. Patients under legal protection (tutorship / guardianship)