Narrative review (European Respiratory Review)

• Focus: infections in nonresolving ARDS (>5 days ventilation)
• Key pathogens:
  • Aspergillus (IAPA, CAPA)
  • CMV, HSV reactivation
• Fungal:
  • ~20% in severe viral pneumonia ICU cohorts
  • ~50% mortality
  • IAPA early vs CAPA later
• Viral:
  • HSV: 16%–64% in ventilated patients
  • CMV: less frequent, later onset
  • PCR ≠ active infection
• Diagnostics:
  • No gold standard
  • BAL preferred over blood for CMV
  • Colonization vs infection difficult
• Treatment:
  • Antifungals may help (observational data)
  • Antivirals unclear benefit
  • No strong RCT evidence for CMV/HSV
• Key concept:
  • self-reinforcing cycle of infection + lung injury + immune dysregulation
• Limitations:
  • heterogeneity
  • sampling variability
  • immortal time bias
• Future:
  • viral load thresholds
  • biomarkers
  • prophylaxis strategies