ARDS is best described as which type of edema?

ARDS is best described as which type of edema?

• A. Cardiogenic edema
• B. Hypoxic pulmonary edema
• C. Non-cardiogenic edema due to alveolar damage
• D. Pleural effusion

Answer: (C)

In ARDS, the edema is noncardiogenic because the primary problem is injury to the alveolar-capillary barrier that increases vascular permeability. This allows protein-rich fluid to leak into the interstitium and the alveolar spaces, flooding the lungs independently of heart pressures. Since the edema isn’t driven by elevated left-sided filling pressures, cardiac pressures are typically normal or near normal, and the fluid produced is exudative rather than transudative. This alveolar flooding with inflammatory fluid impairs gas exchange and causes severe hypoxemia. Pleural effusion represents fluid in the pleural space, not edema within the lung parenchyma. Cardiogenic edema, by contrast, results from elevated hydrostatic pressures from heart failure and tends to be transudative due to increased capillary hydrostatic pressure, not the permeability-driven leak seen in ARDS.

In ARDS, the edema is noncardiogenic because the primary problem is injury to the alveolar-capillary barrier that increases vascular permeability. This allows protein-rich fluid to leak into the interstitium and the alveolar spaces, flooding the lungs independently of heart pressures. Since the edema isn’t driven by elevated left-sided filling pressures, cardiac pressures are typically normal or near normal, and the fluid produced is exudative rather than transudative. This alveolar flooding with inflammatory fluid impairs gas exchange and causes severe hypoxemia.

Pleural effusion represents fluid in the pleural space, not edema within the lung parenchyma. Cardiogenic edema, by contrast, results from elevated hydrostatic pressures from heart failure and tends to be transudative due to increased capillary hydrostatic pressure, not the permeability-driven leak seen in ARDS.