The role of helium in exercise rehabilitation for patients with severe chronic obstructive pulmonary disease. A prospective, double-blind, randomized study. Helium-oxygen mixture versus air - HELIUM

INTERVENTION: Product Name: HELIOX Pharmaceutical Form: Inhalation gas CONDITION: Exercise rehabilitation of patients with severe obstructive pulmonary disease; MedDRA version: 9.1 Level: LLT Classification code 10009033 Term: Chronic obstructive pulmonary disease PRIMARY OUTCOME: Main Objective: To demonstrate, after a rehabilitation program for severe COPD, a greater increase in endurance capacity with the use of the Helium-Oxygen mixture compared to ambient air (plus or minus O2 in the two study groups to maintain an SaO2 of 90%) Primary end point(s): Difference in duration of exercise on a bicycle during the endurance test at 80% of maximum power performed at the beginning and end of the rehabilitation program between each group. The constant-load exercise test (or endurance test) is the most discriminating method for demonstrating functional improvement in a therapeutic trial. Secondary Objective: - To define a functional profile of patients who would benefit from the use of helium. Will patients who show little or no improvement under helium compared to ambient air at the initial assessment be less responsive to helium rehabilitation than those who show significant improvement? - To measure the evolution of the variation in the level of dyspnea and lower limb fatigue and compare between the two groups of patients; - To document the reason for discontinuation, if applicable, of walking tests, exercise tests, and endurance tests and compare between the two groups; - To evaluate the kinetics of improvement in endurance capacity during the weekly walking test. - Describe the pathophysiological mechanism of action of helium during exercise and specify the pathophysiological mechanism of the observed improvement during endurance tests and assessment of the intensity of muscular effort by comparing tests in air and tests with HELIOX in all patients in the study. INCLUSION CRITERIA: - patients with severe COPD (FEV1 = 50% of predicted FEV1) - patients over 18 years of age - able-bodied patients (able to walk and cycle on a cycle ergometer) - hospitalized in a specialized center for respiratory rehabilitation - patients with a resting PaO2 in air >50 mm Hg - complete cessation of smoking, regardless of the time elapsed - BMI ≥ 16 and ≥ 35 - patients who have signed the written consent form to participate in the study after receiving and reading the information on the proposed study, in accordance with good clinical practice and law no. 2004-806 of the Public Health Code. - patient who tested and tolerated the interface (mask) during the air endurance test of the inclusion assessment - patients affiliated (or beneficiary) of a social security scheme Are the trial subjects under 18? no Number of subjects for this age range: F.1.2 Adults (18-64 years) yes F.1.2.1 Number of subjects for this age range F.