Acute,diffuse,inflammatory lung injury associated with variety of etiologies

Acute,diffuse,inflammatory lung injury associated with variety of etiologies.

Clinical diagnosis(Berlin definition)
All of the following criteria should be present

  1. Respiratory Distress within 7 days.
  2. Bilateral lung opacities on chest xray or CT.
  3. Respiratory failure not explained by heart failure or volume overload.
  4. PaO2/FiO2 < 300

Severity of ARDS (based on PaO2/FiO2)
Mild : > 200 <= 300
Mod : > 100 <= 200
Sev : <= 100
Note - if ABG is not available then in place of PaO2/FiO2 , SaO2/FiO2 can also be taken with value 315.

Direct - Pneumonia, Aspiration, Inhalational lung injury, Chest trauma, Near drowning
Indirect - Sepsis, Shock, Trauma, Cardiopulmonary bypass, TRALI, Burns, Increased ICT.

Fluids accumulation in the lungs not explained by heart failure ( noncardiogenic pulmonary edema). Triggering event is cytokine mediated endothelial leak followed by migration of inflammatory cells.

Lung - pulmonary embolism, barotrauma, VAP
GI - ulcer , bacterial translocation, bleeding
Neuro - Hypoxic brain injury
Cardiac - arrhythmia, myocardial dysfunction
Renal - AKI
Others - malnutrition, pneumothorax, electrolyte imbalance, atelectasis, multiorgan dysfunction, DVT,etc

Usually supportive. If etiology found then treating etiology like sepsis with antibiotics.
Mechanical ventilation- Low tidal volume
Usually no role of corticosteroids.
Muscle relaxant
Fluid management
Prone ventilation
Extracorporeal membrane oxygenation (ECMO)

Poor with mortality more than 40%
I have tried to cover important MCQ points only