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-termoxygen therapy (LTOT) criteria):

• Previously established on long-term oxygen therapy according to the followingcriteria: PaO2 < 7.3kPa or <8kPa with polycythemia, pulmonary hypertension orright heart failure on room air in stable condition Or
• PaO2 < 7.3kPa or <8kPa with polycythemia, pulmonary hypertension or right heartfailure 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 1month and an blood pregnancy test by β-HCG negative at the screening visit, during theduration of the study
7. For menopausal woman: confirmatory diagnosis (amenorrhea not medically induced for atleast 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 ofOSA will be over-ruled in patient that had a previous overnight polygraphy. Forpatients who never had an overnight polygraphy, screening for OSA will be made usingthe 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 beexcluded.

4. BMI > 35 kg/m2
5. Patient admitted for an acute COVID-19 infection
6. Hypercapnic respiratory failure justifying NIV defined as
7. An Arterial Blood Gas (ABG) PaCO2 > 7 kPa in stable condition within 6 months
8. Patients with ABG PaCO2 > 7 kPa at hospital discharge and that remainedhypercapnic between 2- and 4-weeks following discharge
9. Pregnancy (blood pregnancy test positive) or lactation ongoing
10. Significant psychiatric disorder or dementia that would prevent adherence to studyprotocol
11. Tobacco use < 10 pack-year
12. Expected survival < 12 months due to any situation other than COPD disease
13. Refusal of high-flow oxygen therapy
14. Person deprived of liberty by administrative or judicial decision or placed underjudicial protection (guardianship or supervision)
15. Patients already involved in a research protocol that would impact with the outcomemeasured in the current protocol