Automated Adjustment of Oxygen on Patient With Acute COPD Exacerbation - FreeO2 HypHop

Inclusion Criteria: * COPD or suspected COPD ( Age\>40, active or smoking history \> 10pack/years), - * Acute exacerbation (increasing dyspnea recently) * One or more of the following criteria: increased sputum, modification of sputum purulence,increased dyspnea, * Moderate oxygen therapy: Oxygen flow \< 8 lpm (or FiO2 \< 0.60) to maintain a SpO2 \>or = 92% (for long term oxygen therapy, the oxygen flow must be greater than baseline flow to maintain SpO2 \> or = 92%) Exclusion Criteria: * Patient refusal * COPD exacerbation with diagnosis highly related to pulmonary embolism, cardiac pulmonary edema, pneumothorax or sedative overdose * No SpO2 signal * Encephalopathy score \> 2 * Delirium * Other respiratory support needed (intubation or NIV) * Patient on withdrawal life support * Advance neoplasia (palliative stage) or terminal respiratory distress * Unavailability of FreeO2 device at the randomisation * Non optimal patient collaboration