Acute Respiratory Distress Syndrome (ARDS)

ARDS is a life-threatening form of respiratory failure characterized by acute onset, bilateral pulmonary infiltrates, severe hypoxemia (P/F ≤300), and absence of cardiogenic pulmonary edema. The 2023 Global Definition expanded ARDS to include non-intubated patients on high-flow nasal cannula or NIV.

• 1Berlin Definition (2012): Mild P/F 200–300, Moderate P/F 100–200, Severe P/F <100
• 22023 Global Definition: expanded to include HFNC (≥30 L/min) and NIV/CPAP (PEEP ≥5)
• 3Lung-protective ventilation: 6 ml/kg PBW, plateau ≤30 cmH₂O, driving pressure <15 cmH₂O
• 4Prone positioning ≥16h/day for severe ARDS (P/F <150) — PROSEVA trial
• 5Conservative fluid strategy after initial resuscitation (FACTT trial)
• 6PEEP titration: higher PEEP for moderate-severe ARDS
• 7Neuromuscular blockade: no longer routinely recommended (ROSE trial)

• Driving pressure = plateau pressure − PEEP; target <15 cmH₂O (stronger predictor of outcome than tidal volume alone)
• Permissive hypercapnia is acceptable — prioritize lung protection over normocapnia
• iNO improves oxygenation but not mortality — use as bridge to ECMO or prone
• ECMO (VV-ECMO) for refractory ARDS — EOLIA trial: no mortality benefit but high crossover rate