A 45-year-old male with community-acquired pneumonia develops acute respiratory distress over 3 days. Chest X-ray shows bilateral diffuse opacities. Arterial blood gas on FiO2 0.6 and PEEP 8 cm H2O shows PaO2 85 mmHg. Lung biopsy (performed for diagnostic confirmation) reveals the structure marked **C** in the diagram — pink eosinophilic linings lining the distal alveolar walls composed of fibrin, plasma proteins, and necrotic cellular debris. Which of the following management strategies has demonstrated mortality benefit in this clinical scenario according to landmark trials?