Home High Flow Oxygen to Reduce Acute Exacerbation of COPD

Inclusion Criteria: 1. Patient with a diagnosis of COPD defined by GOLD guidelines 2. Admitted in hospital for AECOPD 3. With severe respiratory impairment defined by one of the following criteria (long-term oxygen therapy (LTOT) criteria): * Previously established on long-term oxygen therapy according to the following criteria: PaO2 \< 7.3kPa or \<8kPa with polycythemia, pulmonary hypertension or right heart failure on room air in stable condition Or * PaO2 \< 7.3kPa or \<8kPa with polycythemia, pulmonary hypertension or right heart failure on room air after clinical stabilization during the index admission 4. Patients affiliated or, beneficiary of a social security cover 5. Patient who has read and understood the information letter and signed the consent form 6. For woman of childbearing potential, use of an effective contraception (oestro-progestatives or intra-uterine device or tubal ligation) since at least 1 month and an blood pregnancy test by β-HCG negative at the screening visit, during the duration of the study 7. For menopausal woman: confirmatory diagnosis (amenorrhea not medically induced for at least 12 months before the inclusion visit) Exclusion Criteria: 1. Age \<18 or \> 85 years 2. Patient treated with chronic NIV with ongoing treatment 3. Patients diagnosed with obstructive sleep apnea (OSA) treated with CPAP. Diagnosis of OSA will be over-ruled in patient that had a previous overnight polygraphy. For patients who never had an overnight polygraphy, screening for OSA will be made using the STOP-BANG questionnaire. If the results of the STOP-BANG questionnaire (Appendix 1) is \>3, an Apnea-link recording will be performed. If AHI\>30/h, patient will be excluded. 4. BMI \> 35 kg/m2 5. Patient admitted for an acute COVID-19 infection 6. Hypercapnic respiratory failure justifying NIV defined as 1. An Arterial Blood Gas (ABG) PaCO2 \> 7 kPa in stable condition within 6 months 2. Patients with ABG PaCO2 \> 7 kPa at hospital discharge and that remained hypercapnic between 2- and 4-weeks following discharge 7. Pregnancy (blood pregnancy test positive) or lactation ongoing 8. Significant psychiatric disorder or dementia that would prevent adherence to study protocol 9. Tobacco use \< 10 pack-year 10. Expected survival \< 12 months due to any situation other than COPD disease 11. Refusal of high-flow oxygen therapy 12. Person deprived of liberty by administrative or judicial decision or placed under judicial protection (guardianship or supervision) 13. Patients already involved in a research protocol that would impact with the outcome measured in the current protocol