Bronchodilator Response Calculation - Medical Algorithm

The response to inhaled bronchodilator is helpful in distinguishing between chronic obstructive lung disease (COLD) and asthma.

In chronic obstructive lung disease the airway resistance is relatively fixed and unresponsive to inhalation of a bronchodilator.

In asthma the 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	< 1.05	< 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	>= 1.25	>= 2.00

To read more or access our algorithms and calculators, please log in or register.

Bronchodilator Response