title: The clinical significance of volume-adjusted maximal mid-expiratory flow (Iso-volume FEF25-75%) in assessing airway responsiveness to inhaled bronchodilator in asthmatics.
abstract: The clinical significance of Iso-volume FEF25-75% in assessing airway responsiveness to an inhaled bronchodilator was evaluated in 167 asthmatics who presented with variable degrees of airway dysfunction. Iso-volume FEF25-75% identified responsiveness in one patient (5%) out of 20 of the most dysfunctional asthmatics, in three (20%) out of 15 of the least dysfunctional asthmatics and over-all in four (8%) out of 47 asthmatics not showing significant responsiveness via the FEV1. Over-all, FEV1 identified significant responsiveness in more patients (68.6%) than did the Iso-volume FEF25-75% (61%). The authors conclude that the Iso-volume FEF25-75% adds little to the FEV1 in the assessment of obviously dysfunctional asthmatics, the FEF25-75% as conventionally measured is a relatively useless post-bronchodilator measurement and that the FEV1 remains the single best spirometric test with which to assess airway responsiveness in asthmatics.
mesh_terms: D000281:Administration, Intranasal; D000293:Adolescent; D000328:Adult; D000368:Aged; D000402:Airway Obstruction / Q000175:diagnosis*; D000605:Amino Alcohols / Q000627:therapeutic use*; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D002648:Child; D005541:Forced Expiratory Volume; D006801:Humans; D007528:Isoetharine / Q000008:administration & dosage / Q000627:therapeutic use*; D008450:Maximal Midexpiratory Flow Rate; D008875:Middle Aged; D014797:Vital Capacity
chemical_list: D000605:Amino Alcohols; D001993:Bronchodilator Agents; D007528:Isoetharine