Innovation in NOn Invasive Ventilation in COPD Patients Treated by Long Term Oxygen Therapy

Inclusion Criteria: * chronic obstructive pulmonary disease (COPD) * on long term oxygen therapy (LTOT) * affiliated to French social security system or equivalent * informed consent signed Exclusion Criteria: * Diurnal PtCO2 \>55mmHg * Patient who has had an exacerbation of COPD requiring a change in management or treatment in the last 4 weeks prior to the inclusion visit. * Pregnant or breathfeeding women * Prisonners or persons who require protection by the law * Exclusion period from another study * Persons who, according to the investigator, are expected no to meet all study obligations