Acute Respiratory Distress Syndrome Medical Slides

Present the four required criteria: (1) acute onset within 1 week of known insult, (2) bilateral opacities not fully explained by effusions/atelectasis on chest imaging, (3) respiratory failure not fully explained by cardiac failure or fluid overload, (4) PaO2/FiO2 ratio categorization — mild 200-300, moderate 100-200, severe <100 mmHg with PEEP ≥5 cmH2O. Emphasize that the Berlin Definition replaced the 1994 AECC criteria by removing the acute lung injury category.

Present the ARMA trial (2000) protocol: tidal volume 6 mL/kg ideal body weight (reduced from traditional 12 mL/kg), plateau pressure ≤30 cmH2O, PEEP titrated per FiO2/PEEP table, pH target 7.30-7.45. This strategy reduced mortality from 39.8% to 31.0% (22% relative reduction). Include the ARDSNet PEEP/FiO2 tables (lower and higher PEEP strategies).

Reference the PROSEVA trial (2013): early prone positioning (≥16 hours/day) in severe ARDS (PaO2/FiO2 <150) reduced 28-day mortality from 32.8% to 16.0% (NNT=6). Present indications, contraindications (spinal instability, open abdomen, facial surgery), and the physiological rationale — improved V/Q matching, reduced ventral lung compression, and more homogeneous ventilation distribution.