Inspiratory crackles in patients without excess secretions are most commonly associated with which of the following?

a. Reduced chest-wall sound transmission
b. Airways popping open during inspiration
c. Complete obstruction of the upper airway
d. Mucosal edema or inflammation

ANS: B
Crackles also may be heard in patients without excess secretions. These crackles occur when col-lapsed airways pop open during inspiration. Airway collapse or closure can occur in peripheral bronchioles or in larger, more proximal bronchi.