What is a common feature of patients experiencing acute respiratory distress syndrome (ARDS)?

In acute respiratory distress syndrome (ARDS), a notable characteristic is the presence of unexplained respiratory failure. This condition is marked by a sudden increase in pulmonary permeability, leading to the accumulation of fluid in the alveoli, and resultant severe impairment of gas exchange. Patients often experience significant hypoxemia and can quickly deteriorate, which can be difficult to explain by other underlying conditions or factors alone.

These patients typically present with a significant increase in work of breathing and require close monitoring and often mechanical ventilation due to the acute nature of their respiratory failure. The term "unexplained" emphasizes that the respiratory failure cannot be attributed merely to underlying chronic disease or other clear causes, which is a hallmark aspect of ARDS.

Other options don't align as well with ARDS presentation. For example, low pulmonary capillary wedge pressure is usually associated with cardiogenic pulmonary edema rather than ARDS, which typically has a normal or increased wedge pressure due to non-cardiogenic causes. Normal lung sounds on auscultation would be unusual in ARDS where crackles or diminished lung sounds are expected due to the presence of fluid in the alveoli. Lastly, while supplemental oxygen is often given in ARDS, patients do not typically improve oxygenation sufficiently with it,