In burn-inhalation injuries, which combination most contributes to ARDS development?

• A. Dehydration
• B. Oxygen toxicity
• C. Bacterial pneumonia alone
• D. Inhalation injury and sepsis increasing alveolar-capillary permeability

Answer: (D)

The key idea is that ARDS after burn-inhalation injury comes from a combination that directly damages the alveolar-capillary barrier and ramps up inflammation. Inhalation injury causes direct damage to the airways and alveoli, with edema, airway obstruction, soot, and surfactant dysfunction, setting the stage for fluid and inflammatory cells to flood the alveolar spaces. When sepsis enters the picture, inflammatory mediators and neutrophils surge systemically, increasing endothelial and epithelial permeability throughout the lungs. This two-hit scenario—direct alveolar-capillary injury plus a systemic inflammatory response—drives diffuse alveolar damage and severe hypoxemia characteristic of ARDS.

Dehydration on its own doesn’t create the same widespread alveolar-capillary leak or inflammatory cascade needed for ARDS. Oxygen toxicity can contribute to lung injury but requires prolonged exposure to very high oxygen levels and is not the primary driver in this burn-inhalation context. Bacterial pneumonia alone can cause lung infection, but without the systemic inflammatory amplification from sepsis and the initial inhalation injury, it is less likely to produce the full ARDS pattern seen in these patients.