GAV

1)    Patient treated with chronic NIV or CPAP device, with ongoing treatment;

2)    Primary diagnosis of restrictive lung disease causing hypercapnia i.e. obesity hypoventilation and chest wall disease, however these patients will be included if the FEV1/FVC ratio is <60% and the FEV1 <50% if the predominant defect is considered to be obstructive by the center clinician;

3)    BMI > 35 kg/m2;

4)    Sedative medication causing hypercapnia (> 3 drugs or more than 20mg of morphin/day);

5)    Polygraphic diagnosis of Obstructive Sleep Apnoea Syndrome (AHI>30/h (French criteria);

6)    Cognitive impairment that would prevent informed consent into the trial

7)    Pregnancy;

8)    Tobacco use < 10 pack-year;

9)     Psychiatric disease necessitating anti-psychotic medication, ongoing treatment for drug or alcohol addiction, persons of no fixed abode post-discharge;

10)  Unstable coronary artery syndrome;

11)  Age <18 years;

12)  Inability to comply with the protocol;

13)  Expected survival<12 months due to any situation other than COPD disease;

14)  Duration of ICU stay>10 days;

15)  No affiliated to national health insurance.