This study is aiming at evaluating whether low frequency ultrasound spectroscopy is a sensitive tool to detect broncholytic effects in patients with obstructive airway diseases.

Inclusion Criteria:

• • 18 - 70 years

  • for the healthy cohort:

    • FEV1 > 80 % pred, FEV1/FVC ≥ 70 % pred., no history of allergies or asthma
    • nonsmokers, with a history of less than 1 packyear having been nonsmokers for at least the last five years

  • for the COPD cohort: COPD GOLD I to IV according to current guidelines (2)

  • for the asthma cohort: history of asthma GINA I to IV according to current guidelines (3)

  • BMI ≤ 30 kg/m2

  • Able and willing to give written informed consent

  • Available to complete all study measurements

Exclusion Criteria:

• • medical conditions which prohibit the use of salbutamol

  • recent exacerbation of COPD or asthma or lower respiratory tract infection (four weeks previous to informed consent visit)
  • past or present disease, which as judged by the investigator, may affect the outcome of the study. These diseases include, but are not limited to, cardiovascular disease, malignancy, hepatic disease, renal disease, hematological disease, neurological disease, psychiatric disease, endocrine disease or pulmonary disease (including but not confined to asthma, tuberculosis, bronchiectasis or cystic fibrosis)
  • history of drug or alcohol abuse which would interfere with the subject's proper completion of the protocol assignment
  • risk of non-compliance with study procedures
  • suspected inability to understand the protocol requirements, instructions and study-related restrictions, the nature, scope, and possible consequences of the study.