Pathophysiology

• Direct Injury → Regional consolidation from destruction of alveolar architecture
• Indirect Injury → Pulmonary vascular congestion, interstitial edema and less severe alveolar involvement
• Characterized by systemic inflammation:
  • Activation of complement and coagulation systems
  • Stimulation of inflammatory cells
  • Release of proinflammatory mediators
  • Sequestration of neutrophils in microvasculature
  • Endothelial and epithelial disruption
• Failure of hypoxic vasoconstriction resulting in severe hypoxemia

Symptoms