Which respiratory sound indicates fluid in the lungs?

• A. Wheezes
• B. Crackles (rales)
• C. Rhonchi
• D. Stridor

Answer: (A)

Crackles (also called rales) are the sounds you hear when air moves through small, fluid-filled airways or through alveoli that are reopening after being collapsed. This fluid accumulation is common in conditions like pulmonary edema or pneumonia, so crackles are a classic sign of fluid in the lungs. They’re usually heard during inspiration and can be described as fine or coarse depending on the size of the airways involved.

Wheezes are continuous musical sounds from narrowed airways, indicating obstruction rather than fluid. Rhonchi are lower-pitched, snoring sounds from secretions in larger airways. Stridor is a harsh, high-pitched sound due to upper airway obstruction. So crackles best indicate fluid in the lungs.