Acute respiratory distress syndrome

• ARDS - acute lung injury w/ PaO2/FIO2 < 200;
• def: acute bilateral pul. Infiltrates + hypoxemia w/o ↑ left atrial filling pressure;
• causes: sepsis, trauma w/ multiple transfusions, aspiration, diffuse pneumonia;
• patho: diffuse alveolar damage w/ hyaline membranes and protein-rich edema fluid in alveoli;
• PaO/FiO:
  • mild 200-300;
  • moderate 100-200;
  • severe ≤100);
• Tx: PEEP (“lung protective ventilation” = tidal volumes setting - 6 mL/kg * ideal body weight; MOA: ↑ functional residual capacity)

Clinical Features of ARDS

1. Acute onset
2. Bilateral infiltrates on frontal chest x-ray
3. PaO2/FIO2 ≤ 300 mm Hg
4. No evidence of left heart failure or fluid overload
5. The presence of a predisposing condition

NB! This differs from earlier definitions of ARDS, which required a PaO2/FIO2 ≤ 200 mm Hg for the Dx of ARDS MORINIO ICU