Definitions

• Ventilator-Induced Lung Injury (VILI): Acute Lung Injury Caused by Mechanical Ventilation
• Ventilator-Associated Lung Injury (VALI): Acute Lung Injury Associated with Mechanical Ventilation (Used if Unable to Determine if the Injury is Due to Mechanical Ventilation Itself or Due to Worsening of the Underlying Disease Process)
  • Most Commonly Noted in Patients with ARDS but Can Be Seen in Patients with Any Indication for Mechanical Ventilation
• *Terms are Often Used Interchangeably and Some Describe VILI as the “Process” of Injury with VALI as the Resulting Condition

Mechanisms of Injury

• Volutrauma – Trauma from Increased Volume Causing Alveolar Over-Distention
  • Generally Considered to Have Increased Risk with Volumes ≥ 6 mL/kg Ideal Body Weight
  • Heterogenous Consolidation or Atelectasis (ARDS) Can Cause Regional Overdistention Even with Lower Tidal Volumes
• Barotrauma – Trauma from High Inspiratory Pressure Causing Alveolar Over-Distention
  • Can Cause Alveolar Rupture with Air Leakage, Pneumothorax, and Pneumomediastinum
• Atelectrauma – Trauma from the Shear-Stress Created by the Cyclic Opening (Recruitment) and Collapse (De-Recruitment) in Atelectatic Alveoli
  • Stress is Exacerbated by Lung Inhomogeneity (Seen in Atelectasis, ARDS, Surfactant Deficiency, and Pulmonary Edema)
• Biotrauma – Additional Injury Due to the Inflammatory Response to Mechanical Injury
  • Inflammatory Mediators are Increased (Neutrophils, Macrophages, TNF-alpha, IL-6, etc.)

Presentation

• Worsening Hypoxemia
• Tachycardia
• Tachypnea
• Worsening Bilateral Opacities on Chest Imaging
• New or Worsening Organ Failure

Management

• Diagnosis is Clinical
• Management is Primarily with Lung Protective Ventilation, Similar to the Management of ARDS
  • Use Low Tidal Volumes (6 mL/kg Ideal Body Weight)
  • Avoid Elevated Plateau Pressures > 30 cm H2O
  • *See Acute Respiratory Distress Syndrome (ARDS)
• Adjuncts:
  • Systemic Glucocorticoids (Steroids)
  • Inhaled Pulmonary Vasodilators (Nitric Oxide/Prostacyclin)
  • Paralysis/Neuromuscular Blockade
  • Prone Positioning
  • Extracorporeal Membrane Oxygenation (ECMO)
  • Alternative Modes of Ventilation:
    • Airway Pressure Release Ventilation (APRV)
    • High-Frequency Oscillatory Ventilation (HFOV)