Which statement best describes ARDS?

Which statement best describes ARDS?

• A. Non-cardiogenic alveolar edema
• B. Cardiogenic edema
• C. Bacterial pneumonia only
• D. Asthma attack

Answer: (A)

ARDS is defined by edema in the lungs that is not due to heart failure. The injury to the alveolar-capillary barrier causes leakage of fluid and protein into the air spaces, producing non-cardiogenic edema with diffuse alveolar damage. This leads to stiff, low-compliance lungs and severe hypoxemia that may require high oxygen and PEEP. The heart’s pumping ability isn’t the source of the edema, so left-sided pressures are typically normal or not elevated. In contrast, cardiogenic edema arises from high hydrostatic pressures from heart failure, not from permeability injury. Pneumonia or an asthma attack can accompany or precipitate ARDS, but the defining feature is non-cardiogenic alveolar edema driven by inflammatory permeability changes. Thus, the best description is non-cardiogenic alveolar edema.

ARDS is defined by edema in the lungs that is not due to heart failure. The injury to the alveolar-capillary barrier causes leakage of fluid and protein into the air spaces, producing non-cardiogenic edema with diffuse alveolar damage. This leads to stiff, low-compliance lungs and severe hypoxemia that may require high oxygen and PEEP. The heart’s pumping ability isn’t the source of the edema, so left-sided pressures are typically normal or not elevated. In contrast, cardiogenic edema arises from high hydrostatic pressures from heart failure, not from permeability injury. Pneumonia or an asthma attack can accompany or precipitate ARDS, but the defining feature is non-cardiogenic alveolar edema driven by inflammatory permeability changes. Thus, the best description is non-cardiogenic alveolar edema.