title: THE FRACTION OF EXHALED NITRIC OXIDE (FENO) AND FORCED OSCILLATION TECHNIQUE (FOT) CAN PREDICT BRONCHIAL HYPERRESPONSIVENESS AGAINST ACETYLCHOLINE IN TREATED ASTHMATICS.
abstract: The bronchial hyperresponsiveness (BHR) test is useful to diagnose or evaluate effect of therapy in asthmatics, but invasive. On the other hands, the fraction of exhaled nitric oxide (FENO) is a useful noninvasive marker of eosinophilic airway inflammation in asthmatics. And also, the forced oscillation technique (FOT) is a noninvasive method that is used to measure respiratory mechanics, including respiratory resistance and reactance at multiple frequencies.
  
  
  
  To evaluate the complementary roles of FENO and FOT to predict bronchial hyperresponsiveness in adult stable asthmatic patients taking inhaled corticosteroids.
  
  
  
  From our outpatient clinic, we recruited 115 stable asthmatics that were being treated with inhaled corticosteroids at the time of the study. For each subject, we measured FENO by using an offline methods (CEIS' method); and we measured resistance at 5Hz (R5), resistance at 20Hz (R20), R5-R20, reactance at 5Hz (X5), frequency of resonance (Fres), and low-frequency reactance area (ALX), by using a MostGraph FOT machine. We also used spirometry to test BHR to acetylcholine (PC20Ach).
  
  
  
  LogPC20Achwas significantly correlated with FENO, R5, R20, R5-R20 and %FEV1. The ROC curve decided that the cutoff point of FENO was 37.8ppb (AUC=0.647, sensitivity 83.3%, specificity 55.6%, p=0.007) and that of R5 was 3.03cmH2O/L/S (AUC=0.684, sensitivity 72.2%, specificity 52.8%, p=0.001) and that of R20 was 2.77cmH2O/L/S (AUC=0.684, sensitivity 74.5%, specificity 59.4%, p=0.001). When R5 was >3.03 and FENO was >37.8ppb, 25 of 38 subjects (65.7%) had bronchial hyperresponsiveness. If R5 was <3.03 and FENO was <37.8 ppb, only 5 of 29 (17.2%) subjects had. When R20 was >2.77 and FENO was >37.8ppb, 29 of 43 subjects (67.4%) had bronchial hyperresponsiveness. If R20 was <3.03 and FENO was <37.8ppb, only 2 of 18 (11.1%) subjects had.
  
  
  
  Combining R5 or R20 and FENO can predict the level of bronchial hyperresponsiveness in adult stable asthmatics.
authors.affiliation: Clinical Research Center for Allergy and Rheumatology, National Hospital Organization, Sagamihara National Hospital.
authors.forename: Masanori
authors.initials: M
authors.lastname: Fukuhara
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tsuburai
authors.forename: Yuto
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tomita
authors.forename: Yuto
authors.initials: Y
authors.lastname: Hamada
authors.forename: Kentaro
authors.initials: K
authors.lastname: Watai
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hayashi
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Kamide
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Sekiya
authors.forename: Chihiro
authors.initials: C
authors.lastname: Mitsui
authors.forename: Yuma
authors.initials: Y
authors.lastname: Fukutomi
authors.forename: Akio
authors.initials: A
authors.lastname: Mori
authors.forename: Masami
authors.initials: M
authors.lastname: Taniguchi
mesh_terms: D000109:Acetylcholine / Q000276:immunology*; D001249:Asthma / Q000276:immunology / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000175:diagnosis / Q000276:immunology / Q000503:physiopathology*; D045853:Exhalation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D012129:Respiratory Function Tests
chemical_list: D009569:Nitric Oxide; D000109:Acetylcholine