Final Answer:
Crackles on auscultation is the cardinal sign of ARDS (Acute Respiratory Distress Syndrome), characterized by the presence of fluids in the alveoli.Thus option c is the correct answer.
Step-by-step explanation:
The cardinal sign of Acute Respiratory Distress Syndrome (ARDS) is the presence of crackles on auscultation. These crackles, also known as rales, indicate the accumulation of fluid in the alveoli, which compromises the exchange of oxygen and carbon dioxide in the lungs. While cyanosis, increased respiratory rate, and hypertension may be associated with ARDS, the distinctive clinical marker that directly reflects the alveolar fluid accumulation is the detection of crackles during a physical examination.
Crackles result from the sudden opening of small airways and alveoli that have collapsed or filled with fluid. The sound is often described as a series of discrete, non-musical, and brief noises. These crackles can be heard using a stethoscope during inspiration and sometimes expiration. The presence of crackles is indicative of the underlying pathology in the lungs, highlighting the inflammatory and fluid-filled nature of ARDS.
In summary, while other symptoms such as cyanosis, increased respiratory rate, and hypertension can be associated with ARDS, the definitive clinical manifestation that signifies the presence of fluid in the alveoli is the detection of crackles on auscultation. This underscores the importance of a thorough physical examination, including careful lung auscultation, in diagnosing and managing ARDS.Crackles on auscultation is the cardinal sign of ARDS (Acute Respiratory Distress Syndrome), characterized by the presence of fluids in the alveoli.Thus option c is the correct answer.