What is a critical symptom of acute respiratory distress syndrome (ARDS)?

Decreased oxygen saturation is a critical symptom of acute respiratory distress syndrome (ARDS) because this condition is characterized by a significant impairment in gas exchange due to inflammation and fluid accumulation in the alveoli of the lungs. In ARDS, the alveoli become filled with fluid, which hampers the lungs' ability to deliver oxygen to the bloodstream effectively. As a result, a pronounced drop in oxygen saturation levels occurs, typically measured using pulse oximetry.

Patients may exhibit hypoxemia, which is a below-normal level of oxygen in the blood. This symptom is particularly alarming because it can lead to respiratory failure and requires immediate medical intervention. Monitoring oxygen saturation is thus crucial in diagnosing and managing ARDS, as it provides insights into the severity of the condition and the effectiveness of oxygen therapy or mechanical ventilation if needed.

The other options do not accurately reflect the hallmark features of ARDS. Increased blood pressure may not be directly correlated, as ARDS is often associated with decreased blood pressure in severe cases due to shock or systemic inflammation. Hyperventilation can occur due to various reasons but is not specific to ARDS and often reflects the body's response to hypoxemia, rather than being a defining symptom. Bradycardia, or slowed heart rate,