What characterizes the improvement observed in post-bronchodilator spirometry for asthma patients?

In the context of asthma management, the improvement in post-bronchodilator spirometry is characterized by a significant increase in forced expiratory volume in one second (FEV1). An increase of at least 12% from the baseline measurement, along with an absolute increase of 200 ml or more, indicates a positive response to bronchodilator therapy. This benchmark is part of the criteria used to evaluate airway responsiveness and assess the effectiveness of asthma treatment.

Asthma involves reversible airway obstruction, and a notable rise in FEV1 post-bronchodilator shows that the airways are responsive to medication, suggesting effective bronchodilation. This improvement is critical for confirming a diagnosis of asthma and for making treatment decisions. Thus, the parameters of a 12% increase and 200 ml reflect a clinically significant response that is routinely used in practice.

The other choices either suggest minimal improvements or deterioration of lung function, which does not align with the expected outcomes in asthmatic patients undergoing bronchodilator therapy.