Inclusion criteria
1) Patients with COPD, GOLD C or D and FEV1<65%;
2) AHRF (pH<7,35 and PaCO2≥45mm Hg (≥6kPa) treated more than 24h with Ventilation (non-invasive or invasive);
3) 48h to 2 weeks with pH>7.35, and PaCO2>45 (>6kPa) after NIV withdrawal, during daytime at rest without oxygen or ventilatory support (or with O2 if patients are not able to avoid O2 with immediate desaturation below 80%).
exclusion criteria
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.
