title: FEF25-75 as a marker of airway obstruction in asthmatic children during reduced mite exposure at high altitude.
abstract: Sensitivity of forced expiratory flow between 25% and 75% of the vital capacity (FEF25-75) in detecting airway obstruction was investigated in 14 children with mild-moderate asthma, allergic to house dust mites, while at high altitude (1756 m). Forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), FEF25-75, and peak expiratory flow (PEF) were measured every 2 weeks for 12 weeks (total, 84 measurements). The presence or absence of wheezing at the chest auscultation was ascertained before each test. During the study period, a significant improvement of both mean (SD) FEF25-75 [61 (12)% vs. 68 (11)% of the predicted value, p = 0.005] and PEF [95 (16)% vs. 103 (13)%, p = 0.002] was observed. FEV1 changed only marginally [82 (7)% vs. 86 (6)%, p = 0.05]. Wheezing was present on 12/84 occasions. Wheezing was associated with abnormal FEF25-75 values on most occasions but not with abnormal FEV1 or PEF. FEF25-75 was decreased on 51% of days in which wheezing was absent. FEV1 and PEF were, respectively, normal in 69% (p < 0.0001) and 92% (p < 0.0001) of measurements in which FEF25-75 was abnormal. These results suggest that FEF25-75 may be considered a good indicator of airflow obstruction and a sensitive marker of respiratory improvement in asthmatic children during reduced antigen exposure.
authors.affiliation: Paediatric Clinic, University of Verona, Italy.
authors.forename: E A
authors.initials: EA
authors.lastname: Valletta
authors.forename: G L
authors.initials: GL
authors.lastname: Piacentini
authors.forename: G
authors.initials: G
authors.lastname: Del Col
authors.forename: A L
authors.initials: AL
authors.lastname: Boner
mesh_terms: D000293:Adolescent; D000402:Airway Obstruction / Q000175:diagnosis*; D000531:Altitude; D000818:Animals; D001249:Asthma / Q000503:physiopathology*; D015415:Biomarkers / Q000032:analysis*; D002648:Child; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008450:Maximal Midexpiratory Flow Rate / Q000502:physiology*; D008925:Mites / Q000276:immunology; D012135:Respiratory Sounds / Q000175:diagnosis; D012680:Sensitivity and Specificity; D014797:Vital Capacity / Q000502:physiology
chemical_list: D015415:Biomarkers