When explaining crackles to a patient with respiratory distress, which statement is appropriate?

• A. They are indicative of pleural rubbing.
• B. They are signs of bronchial constriction.
• C. Crackles are located in the smaller air passages.
• D. Crackles are heard during respiratory expiration.

Answer: (C)

Crackles come from the tiny airways and alveoli popping open as you inhale, especially when those distal passages are fluid-filled or collapsed and then reopen. That’s why crackles are described as originating in the smaller air passages. They aren’t the result of pleural rubbing, which is a grating sound from the pleural surfaces; nor do they come from bronchial constriction, which typically causes wheezes. Crackles are usually heard during inspiration when air flow is entering the small airways.