Which statement best describes the diagnostic features of ARDS?

Which statement best describes the diagnostic features of ARDS?

• A. Hypoxemia that responds to high-flow oxygen with unilateral infiltrates
• B. Severe hypoxemia not responsive to high-flow oxygen with bilateral infiltrates; seen in sepsis, burns, pancreatitis
• C. Cardiogenic edema with diffuse interstitial markings
• D. Normal oxygenation with single-lobe pneumonia

Answer: (D)

ARDS is defined by acute onset noncardiogenic pulmonary edema with diffuse bilateral infiltrates and severe hypoxemia that does not fully respond to high concentrations of oxygen. This pattern reflects increased capillary permeability and alveolar edema rather than heart failure, so the heart can be functioning normally yet gas exchange remains severely impaired. Clinically, ARDS often follows insults like sepsis, pancreatitis, burns, or major trauma, appearing within a week and producing diffuse lung involvement on imaging. The best statement captures these features: pinpointing severe hypoxemia that’s not improved by high-flow oxygen, along with bilateral infiltrates on imaging. Unilateral infiltrates or a normal oxygenation with a focal pneumonia are not characteristic of ARDS. Cardiogenic edema implies heart failure with typically different clues (such as elevated left-sided pressures or cardiomegaly), whereas ARDS centers on noncardiogenic edema with diffuse lung involvement.

ARDS is defined by acute onset noncardiogenic pulmonary edema with diffuse bilateral infiltrates and severe hypoxemia that does not fully respond to high concentrations of oxygen. This pattern reflects increased capillary permeability and alveolar edema rather than heart failure, so the heart can be functioning normally yet gas exchange remains severely impaired. Clinically, ARDS often follows insults like sepsis, pancreatitis, burns, or major trauma, appearing within a week and producing diffuse lung involvement on imaging.

The best statement captures these features: pinpointing severe hypoxemia that’s not improved by high-flow oxygen, along with bilateral infiltrates on imaging. Unilateral infiltrates or a normal oxygenation with a focal pneumonia are not characteristic of ARDS. Cardiogenic edema implies heart failure with typically different clues (such as elevated left-sided pressures or cardiomegaly), whereas ARDS centers on noncardiogenic edema with diffuse lung involvement.