title: Usefulness of impulse oscillometry for the assessment of airway hyperresponsiveness in mild-to-moderate adult asthma.
abstract: BACKGROUND
  Impulse oscillometry (IOS) is a novel method of assessing airway resistance. IOS is rarely used in assessing airway resistance after bronchoprovocation in adult asthma.
  
  
  OBJECTIVE
  To ascertain the degree of change in IOS measurements seen in patients with asthma undergoing bronchial challenge testing.
  
  
  METHODS
  Patients 18 to 65 years old with mild to moderate asthma, forced expiratory volume in 1 second (FEV1) greater than 80% predicted, and diurnal FEV1 variation less than 30% and taking inhaled corticosteroid (≤1,000 μg/day of beclomethasone dipropionate equivalent dose) were recruited. Sequential spirometry and IOS results were measured during bronchial challenge testing to inhaled methacholine and histamine.
  
  
  RESULTS
  The magnitude of percentage of change demonstrated in total airway resistance at 5 Hz was greater than that observed for FEV1 in the 2 bronchial challenge tests. For example, at a methacholine provocation concentration that caused a decrease in FEV1 of 20%, a 43.5% change (95% confidence interval 29.4-57.5) was seen in total airway resistance at 5 Hz as measured by IOS compared with a 23.3% change (95% confidence interval 18.7-27.9) in FEV1. The magnitude of change seen with other IOS outcomes, including peripheral airway resistance, area under the curve, and resonant frequency, also was greater compared with spirometry.
  
  
  CONCLUSIONS
  The potential application of IOS in the assessment of airway hyperresponsiveness in adult asthma has been demonstrated. Further population studies are required.
  
  
  BACKGROUND
  www.clinicaltrials.gov (NCT01074853).
authors.affiliation: Scottish Centre for Respiratory Research, Medical Research Institute, Ninewells Hospital, University of Dundee, Dundee, Scotland.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Short
authors.affiliation: Scottish Centre for Respiratory Research, Medical Research Institute, Ninewells Hospital, University of Dundee, Dundee, Scotland.
authors.forename: William J
authors.initials: WJ
authors.lastname: Anderson
authors.affiliation: Scottish Centre for Respiratory Research, Medical Research Institute, Ninewells Hospital, University of Dundee, Dundee, Scotland.
authors.forename: Arvind
authors.initials: A
authors.lastname: Manoharan
authors.affiliation: Scottish Centre for Respiratory Research, Medical Research Institute, Ninewells Hospital, University of Dundee, Dundee, Scotland. Electronic address: b.j.lipworth@dundee.ac.uk.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Lipworth
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000403:Airway Resistance; D019540:Area Under Curve; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000175:diagnosis / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D004311:Double-Blind Method; D005260:Female; D005541:Forced Expiratory Volume; D006632:Histamine; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D009991:Oscillometry / Q000379:methods*; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data; D012189:Retrospective Studies; D013147:Spirometry; D055815:Young Adult
chemical_list: D000305:Adrenal Cortex Hormones; D016210:Methacholine Chloride; D006632:Histamine