What pulmonary function test (PFT) measurement is the best indicator of reversible airway obstruction in response to inhaled bronchodilators?

The best indicator of reversible airway obstruction in response to inhaled bronchodilators is the FEV1 measurement. FEV1, or Forced Expiratory Volume in one second, quantifies how much air a person can forcibly exhale in the first second of a breath. This measurement is particularly sensitive to changes in airflow obstruction, which is a hallmark of conditions such as asthma and chronic obstructive pulmonary disease (COPD).

When patients with asthma or other obstructive lung diseases use bronchodilators, one of the most immediate responses is an increase in the FEV1. A significant improvement in FEV1 after bronchodilator therapy suggests that the patient's airway obstruction is at least partially reversible, providing valuable diagnostic information.

Other pulmonary function tests have their own significance, but they are not as directly indicative of airway reactivity. For example, PEFR (Peak Expiratory Flow Rate) measures the maximum speed of expiration but can be more variable and less precise. FVC (Forced Vital Capacity) reflects the total amount of air exhaled but does not focus on the speed of expiration in the first second. FEF25-75 (Forced Expiratory Flow between 25% and 75% of the pulmonary volume) can