Which lung sound is associated with fluid in the alveoli?

Rales, also known as crackles, are the lung sounds that indicate the presence of fluid within the alveoli. This sound is typically heard during inhalation and is characterized by a series of short, discontinuous, and high-pitched bursts. The presence of fluid can occur in various conditions, such as pulmonary edema, pneumonia, or heart failure, and it reflects the difficulty in air passing through fluid-filled alveoli.

The mechanism behind the sound arises as air moves through the small airways and alveoli that have fluid present, creating the crackling noise. This is particularly relevant in clinical settings because it provides valuable diagnostic information about the patient's respiratory status, guiding further assessment and treatment.

Other lung sounds, like wheezing, are typically associated with bronchoconstriction or inflammation of the airways, stridor indicates upper airway obstruction or severe narrowing, and ronchi are associated with mucus in the larger airways. Each of these sounds serves a different purpose in assessment and reflects different respiratory conditions, but in terms of fluid accumulation in the alveoli specifically, rales or crackles are the definitive sounds noted.