Evaluation by Electrical Impedancemetry of the Variation in Lung Volumes Under Non-invasive Ventilation (NIV) in Patients With Chronic Obstructive Pulmonary Disease (COPD)

Inclusion Criteria: * Patients with COPD in stable condition fitted with long-term NIV followed at Bordeaux University Hospital; * Patient benefiting from social protection from the national health insurance fund; * Patient having read the patient information letter and given his non-objection to participate in the study. Exclusion Criteria: * Obesity with a BMI \> 35; * Respiratory exacerbation during treatment; * Patient with one or more contraindications to the implementation of EIT(7): * Pacemaker, defibrillator, electric active medical device; * Damaged skin condition, dressing on the observation area; * Risk related to fitting the belt (fracture, spinal lesions, etc.); * Uncontrollable movements; * Current electrotherapy; * Presence of a magnetic field (magnetic resonance imaging); * Other bioimpedance measurements in progress; * Pregnant woman ; * Tidal volume \< 1ml/kg; * Patient having read the patient information letter and refusing to participate in the study (Loi Jardé research category 3); * Patient under guardianship, curatorship, or deprived of freedom of administrative or judicial decision; * Patient included in other protocols that may interact with this study;