Acute,diffuse,inflammatory lung injury associated with variety of etiologies.
Clinical diagnosis(Berlin definition)
All of the following criteria should be present
- Respiratory Distress within 7 days.
- Bilateral lung opacities on chest xray or CT.
- Respiratory failure not explained by heart failure or volume overload.
- 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.
Extracorporeal membrane oxygenation (ECMO)
Poor with mortality more than 40%
I have tried to cover important MCQ points only