Question

what decreases the airway resistance that leads to supernormal expiratory flow rate (higher than normal when corrected for lung volume)

Answer 1

Airway resistance can be decreased by increasing airway radius. This can be achieved by increasing outward tethering force on airways which increases as the lungs expand.

Step-by-step explanation:

Inhaled corticosteroids are a common therapy option in the treatment of persistent asthma. They act to decrease airway inflammation and mucus production. This reduction in inflammation and mucus increases the caliber of airways, reducing airway resistance.