title: Impulse oscillometry versus spirometry in a long-term study of controller therapy for pediatric asthma.
abstract: BACKGROUND
  Determination of the benefits and limitations of specific physiologic tests has not been well studied in long-term clinical pediatric trials.
  
  
  OBJECTIVE
  We sought to determine the utility of impulse oscillometry in a long-term comparison of 3 controller regimens in children with persistent asthma.
  
  
  METHODS
  Children 6 to 14 years of age with mild-to-moderate persistent asthma were characterized with oscillometry and spirometry before entry into a clinical trial and then serially during 48 weeks of therapy with either an inhaled corticosteroid, a combination inhaled corticosteroid with a long-acting beta-agonist, or a leukotriene receptor antagonist.
  
  
  RESULTS
  The FEV(1)/forced vital capacity ratio, as well as the forced expiratory flow from 25% to 75% of forced vital capacity in terms of spirometric parameters and the reactance area (XA) from impulse oscillometry, appeared to complement information provided by FEV(1) when comparing the tests and factors that appeared to predict a response to treatment. XA was unique in that it, as distinct from spirometric variables, reflected ongoing improvement during the latter part of the trial. In general, improvements in XA during the latter part of the study occurred independently of indices of atopy and the level of airway responsiveness.
  
  
  CONCLUSIONS
  Assessment of respiratory mechanics over time with oscillometry might offer additional insights into the response of asthmatic patients to therapy. In particular, the pattern of improvement seen in XA over the course of therapy suggests this test might detect alterations in airway mechanics not reflected by spirometry. The possibility that changes in XA reflect ongoing improvement in small airway function deserves additional study.
authors.affiliation: Department of Pediatrics, National Jewish Health, Denver, CO 80206, USA. larseng@njc.org
authors.forename: Gary L
authors.initials: GL
authors.lastname: Larsen
authors.forename: Wayne
authors.initials: W
authors.lastname: Morgan
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Heldt
authors.forename: David T
authors.initials: DT
authors.lastname: Mauger
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Boehmer
authors.forename: Vernon M
authors.initials: VM
authors.lastname: Chinchilli
authors.forename: Robert F
authors.initials: RF
authors.lastname: Lemanske
authors.forename: Fernando
authors.initials: F
authors.lastname: Martinez
authors.forename: Robert C
authors.initials: RC
authors.lastname: Strunk
authors.forename: Stanley J
authors.initials: SJ
authors.lastname: Szefler
authors.forename: Robert S
authors.initials: RS
authors.lastname: Zeiger
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Taussig
authors.forename: Leonard B
authors.initials: LB
authors.lastname: Bacharier
authors.forename: Theresa W
authors.initials: TW
authors.lastname: Guilbert
authors.forename: Shelley
authors.initials: S
authors.lastname: Radford
authors.forename: Christine A
authors.initials: CA
authors.lastname: Sorkness
mesh_terms: D000085:Acetates / Q000008:administration & dosage; D000293:Adolescent; D000420:Albuterol / Q000008:administration & dosage / Q000031:analogs & derivatives; D000730:Androstadienes / Q000008:administration & dosage; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D015415:Biomarkers; D002648:Child; D003521:Cyclopropanes; D004311:Double-Blind Method; D005260:Female; D000068298:Fluticasone; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D009991:Oscillometry; D011804:Quinolines / Q000008:administration & dosage; D000068299:Salmeterol Xinafoate; D013147:Spirometry; D013440:Sulfides; D014797:Vital Capacity
chemical_list: D000085:Acetates; D000730:Androstadienes; D015415:Biomarkers; D003521:Cyclopropanes; D011804:Quinolines; D013440:Sulfides; D000068299:Salmeterol Xinafoate; D000068298:Fluticasone; C093875:montelukast; D000420:Albuterol