Nontypical ARDS in COVID-19: authors argue for a new management approach

  • Gattinoni L & al.
  • Intensive Care Med
  • 14 Apr 2020

  • curated by Liz Scherer
  • Clinical Essentials
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Takeaway

  • COVID-19-related severe acute respiratory distress syndrome (ARDS) presents in 2 ways.
  • 3 factors appear to interact: severity, ventilatory responsiveness to hypoxemia, and time between disease onset and hospitalization.
  • These factors should guide recognition of phenotype and approach to treatment.

Why this matters

  • The authors argue that treatment should rely on establishing the correct pathophysiology within 2 primary phenotypes: Type L and Type H.
  • Use CT scans to identify patient type, or if unavailable, distinguish patients by respiratory system elastance and recruitability.

Key points

  • Type L: 1) low elastance, 2) low ventilation-to-perfusion ratio, 3) low lung weight, 4) low lung recruitability.
    • Course: patient status remains unchanged and then improves or worsens; negative intrathoracic pressure depth linked to increased tidal volume may drive progression to interstitial lung edema and dyspnea, worsening patient "self-inflicted" lung injury and causing transition to Type H.
  • Type H: 1) high elastance, 2) high right-to-left shunt, 3) high lung weight, 4) high lung recruitability. 
    • Fully meets ARDS criteria.

Treatment pearls:

  • Reverse hypoxemia through increased FiO2.
  • Dyspnea: esophageal manometry critical to assess pressure swings, drive noninvasive treatment selection.
  • Inspiratory pleural pressure swing magnitude determines transition to type H, and >15 cmH2O indicates intubation need.
  • If hypercapnic, ventilate with volumes >6 mL/kg to 8-9 mL/kg; use prone positioning for rescue only.
  • Treat type H as severe ARDS.