The principal objective is to show noninferiority of nebulized salbutamol through the high flow nasal system moistened AIRVO ™ 2 in terms of reversibility of airflow obstruction compared to nebulization by the usual method (spray mask).

Randomized, comparative, non inferiority study between two nebulization strategies bronchodilators, one according to the method tested namely the spray - in across the top humidified nasal flow system and the other according to a customary procedure, through a mask. A third arm will be evaluated (control arm) to overcome a possible own bronchodilator effect of high flow nasal humidified.

Inclusion Criteria:

• adults

• Patient with chronic obstructive pulmonary disease

• Patients, when performing lung function tests performed outside of the study :

  1. A report FEV / FVC less than 60% prior to bronchodilator treatment AND
  2. A positive reversal test defined by FEV variation of over 12 % and 200 mL after administration of inhaled salbutamol

• Patients affiliated to social security scheme

• Informed consent signed by the patient

Exclusion Criteria:

• Exacerbation of chronic obstructive pulmonary disease during
• Uncontrolled asthma
• Pneumothorax current or recent ( < 2 months)
• Pleural aspiration or biopsy , trans - bronchial biopsies and / or bronchoalveolar lavage in the preceding 48h
• hemoptysis in progress
• Patient under guardianship or trusteeship safeguard justice
• Pregnant or breastfeeding women or parturient woman
• Known allergy or intolerance to salbutamol