Noncardiogenic Pulmonary Edema

Basics

Description

  • Noncardiogenic pulmonary edema (NCPE) is the accumulation of excess fluid and protein into the alveoli from factors unrelated to elevated hydrostatic pressure (pulmonary capillary pressure is normal):
    • Functional disruption of the capillary–alveolar membrane results in increased permeability
    • Protein and fluid move freely from the intravascular space into the alveolar space
    • Usually bilateral rather than unilateral depending on etiology
  • Distinction between NCPE and cardiogenic pulmonary edema (CPE):
    • NCPE lacks cephalad blood redistribution, cardiomegaly, pulmonary effusions, and systemic volume overload seen in CPE
    • NCPE features alveolar fluid with high protein content due to membrane disruption, unlike protein-poor fluid in CPE
    • Distinguishing NCPE from CPE can be difficult in patients with comorbidities or baseline left ventricular dysfunction
  • ARDS: Severe form of NCPE characterized by diffuse alveolar damage, inflammation, and hypoxemia
  • ARDS accounts for 10–15% of ICU admissions, 23% of ventilated patients
  • Incidence increases with age; highest in individuals 75–84 yr old​
  • Global mortality is 35–45%, increasing with severity
  • More common in men, but outcomes are similar between sexes

Etiology

  • ARDS commonly triggered by direct or indirect lung insults:
    • Sepsis (leading cause)
    • Pneumonia
    • Aspiration
    • Trauma, including major burns
    • Massive transfusion
    • Transfusion-related acute lung injury (TRALI)
    • Inhaled toxins or systemic overdose (ASA and TCA commonly implicated)
    • Pancreatitis
  • High-altitude pulmonary edema (HAPE)
  • Neurogenic pulmonary edema
  • Reperfusion pulmonary edema (following removal of proximal thrombus)
  • Re-expansion pulmonary edema after re-expansion of pneumothorax or drainage of large pleural effusion
  • Drug/toxin exposure:
    • Opioids
    • Salicylates
    • Cocaine
    • Inhaled irritants
    • Chemotherapy agents
  • Pulmonary embolism
  • Viral pneumonias (eg, influenza, SARS-CoV-2)

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