Airflow limitation.
D000402:Airway Obstruction / Q000503:physiopathology*; D000403:Airway Resistance; D003187:Compliance; D005541:Forced Expiratory Volume; D006371:Helium; D006801:Humans; D009584:Nitrogen; D012123:Pulmonary Ventilation; D012129:Respiratory Function Tests
D006371:Helium; D009584:Nitrogen