Overview :
The response to inhaled bronchodilator is helpful in distinguishing between
(1) chronic obstructive lung disease (airway resistance relatively fixed and unresponsive to inhalation of a bronchodilator) and
(2) asthma (bronchoconstriction responds to inhalation of a bronchodilator)
Response to Bronchodilators
FVC (after)-to-FVC (before)
FEV1 (after)-to-FEV1 (before)
FEF(25-75%) (after)-to-FEF(25-75) (before)
not responsive
< 1.05
< 1.10
not clearly responsive
1.05 - 1.14
1.05 - 1.11
1.10 - 1.44
responsive
1.15 - 1.24
1.12 - 1.24
1.45 - 1.99
markedly responsive
>= 1.25
>= 2.00
Fishman A (editor). Pulmonary Diseases and Disorders, Second Edition. McGraw-Hill Book Company. 1988. page 2508