Which is the most common cause of ARDS?

• A. Aspiration
• B. Pneumonia
• C. Trauma
• D. Sepsis

Answer: (D)

Sepsis is the most common trigger of ARDS. When sepsis occurs, a surge of inflammatory mediators circulates through the body, injuring the alveolar-capillary membrane. This injury increases capillary permeability, allowing protein-rich fluid to flood the alveoli and creating noncardiogenic pulmonary edema. The result is rapidly developing hypoxemia and reduced lung compliance, with bilateral infiltrates on imaging characteristic of ARDS. Other events like pneumonia, aspiration, or trauma can also lead to ARDS, but they occur less frequently than sepsis overall. In managing ARDS driven by sepsis, the focus is on treating the infection promptly and supporting the lungs with protective ventilation to minimize further injury.