Which auscultation sound may indicate the presence of fluid in the alveoli?

Crackles, also known as rales, are abnormal lung sounds that are often associated with the presence of fluid in the alveoli or the airways. These sounds can be heard during inspiration as a result of the popping open of small airways and alveoli that have been collapsed or filled with fluid.

When fluid accumulates in the alveoli, such as in conditions like pneumonia or pulmonary edema, it creates a disruptive airflow which contributes to the crackling sound. This phenomenon is a key reason why clinicians listen for crackles during auscultation when evaluating patients for potential respiratory complications.

Other sounds such as wheezes are typically associated with narrowing of the airways, stridor is indicative of an upper airway obstruction, and rhonchi represent low-pitched, snore-like sounds caused by secretions in the larger airways. While these may signal different issues within the respiratory system, crackles specifically point towards fluid presence in the alveoli, making this choice the most appropriate in this context.