Template:COVID-19 Lung Phenotypes

COVID Lung Phenotypes and Their Management

Hypoxemic patients can be divided into two general phenotypes

COVID L Lung Phenotype

• Characterized by Low elastance (i.e., high compliance), Low ventilation to perfusion ratio, Low lung weight and Low recruitability
• Often referred to as the “happy hypoxemic”
• Normal lung volumes and low lung recruitability.
• Hypoxemia may be due to loss of regulation of perfusion and loss of hypoxic vasoconstriction.
• These patients can be damaged iatrogenically if you respond to their pulse ox with standard vent modes
• Do poorly with low tidal volume (TV) and high PEEPs
• Best managed with high FiO2 which allows you to limit the PEEP
• Recommended initial vent settings:
  • 8 ml/kg TV, 100% FiO2
  • Increase the PEEP only if the patient is desaturating on a high FiO2.
  • Can turn into COVID H patients on the vent.

COVID H Lung Phenotype

• Characterized by High elastance, High right-to-left shunt, High lung weight and High recruitability.
• Increased permeability of the lung leads to edema, atelectasis, decreased gas volume, and decreased TV for a given inspiratory pressure.
• High degree of lung recruitability.
• 20 – 30% of patients fit ARDS criteria:
  • Hypoxemia
  • Bilateral infiltrates
  • Decreased the respiratory system compliance
  • Increased lung weight and potential for recruitment
• The ARDS ladder applies only to this subset of COVID patients.