title: Is extrathoracic airway obstruction important in asthma?
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000402:Airway Obstruction / Q000150:complications / Q000503:physiopathology*; D001249:Asthma / Q000209:etiology / Q000503:physiopathology*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005260:Female; D006371:Helium; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen; D011312:Pressure; D012123:Pulmonary Ventilation; D012129:Respiratory Function Tests
chemical_list: D006371:Helium; D010100:Oxygen