ARDS

Non-cardiogenic pulmonary oedema and diffuse lung inflammation, typically secondary to an underlying illness

Aetiology

  • Pulmonary: chest sepsis, aspiration, inhalation injury, pulmonary contusion, and transfusion-related lung injury
  • Non-pulmonary causes: sepsis from a non-pulmonary source, acute pancreatitis, disseminated intravascular coagulation, and drug overdose

Pathophysiology

  • Injury (e.g. sepsis, severe trauma, pneumonia) → inflammation which damages blood vessels → increased permeability of alveolar capillaries → fluid accumulation in the alveoli

Clinical presentation

Symptoms

  • Acute onset respiratory failure which fails to improve with supplemental oxygen, the symptoms of which include severe dyspnoea, confusion, and presyncope

Signs

  • Elevated respiratory rate
  • Bilateral lung crackles (but no other features of heart failure)
  • Low SpO2

Investigations

  • ABGs
  • CXR - bilateral alveolar infiltrates, without other features of heart failure (such as cardiomegaly and Kerley B lines)

Management

  • Oxygen
  • Mechanical ventilation - low tidal volume associated with better outcomes