Benefits of Liquid Oxygen in COPD Patients Presenting Desaturation During Exercise.

Oxygen will be administered through nasal cannulae. Patients will be provided with a tank of liquid oxygen and a rechargeable portable device. The 6 minuts walking test will be used to adjusted oxygen flow in the GFA group (to achieve a mean SpO2 ≥ 90%). In the control group (GC), a 3L/min oxygen flow will be administer. Oxygen is used when the patient perform physical activity. The treatment period for each patient is 6 months (3 months in the GC grup, 3 months in the GFA one).

Inclusion criteria

• Clinical stable moderate to severe COPD (FEV1 <70%, FEV 1 / FVC <70%) total lung capacity (TLC> 80%) without conventional criteria for LTOT, optimal medical therapy, mean SpO2 ≤ 88% during the 6 minuts walking test and active life outside the home, other than active smoking or are in program respiratory rehabilitation.

Exclusion criteria

• Current smokers - Presence of respiratory failure and criteria for LTOT (PO2 <55 mmHg or 55-60 mmHg associated with pulmonary arterial hypertension, chronic cor pulmonale, congestive heart failure, arrhythmias or polycythemia). - Presence of impaired mobility - Cognitive impairment or intellectual disability to fill in questionnaires - No acceptance of liquid oxygen - Presence of active comorbidities (cardiovascular disease, rheumatologic, renal, hepatic) - Participation in pulmonary rehabilitation programs