Describe the ARDS ventilation strategy, including tidal volume, PEEP, plateau pressure, and prone positioning.

• A. High tidal volumes with minimal PEEP, plateau pressures >40 cm H2O.
• B. Moderate tidal volumes with no PEEP; keep plateau pressures around 40 cm H2O.
• C. Lung-protective ventilation with low tidal volumes (4-6 mL/kg PBW), adequate PEEP, plateau pressures ≤30 cm H2O, and prone positioning for severe hypoxemia.
• D. Spontaneous breathing with no PEEP and high FiO2.

Answer: (C)

Protecting the injured lung from ventilator-induced injury is the central idea. In ARDS, the lungs are stiff and prone to overdistension, so the ventilation plan aims to minimize further damage while keeping oxygenation.

The best approach uses lung-protective ventilation with low tidal volumes of about 4–6 mL per kilogram of predicted body weight to limit volutrauma. Keeping plateau pressures at or below 30 cm H2O prevents excessive distending pressure inside the alveoli, reducing the risk of barotrauma. Adequate PEEP is used to keep alveoli open and improve oxygenation, preventing repeated collapse, but it must be balanced against potential hemodynamic compromise. For patients with severe hypoxemia, prone positioning improves oxygenation by more evenly distributing ventilation and perfusion, recruiting dependent (dorsal) lung regions and reducing ventilator-induced injury; this is particularly beneficial when ARDS is moderate to severe and oxygenation remains poor despite optimized PEEP.

Approaches with high tidal volumes or plateau pressures over 30 cm H2O increase the risk of lung injury. No PEEP leads to rapid alveolar collapse and poor oxygenation, and spontaneous breathing with no PEEP and high FiO2 does not provide lung protection and can worsen injury.