Prevalence and etiology of ventilator-associated pneumonia during the COVID-19 pandemic in Denmark: Wave-dependent lessons learned from a mixed-ICU.

Background: Ventilator-associated pneumonia (VAP) may be a particular concern in patients with severe coronavirus disease 2019 (COVID-19). We aimed to determine the prevalence and etiology of VAP in critically ill COVID-19 patients in a Danish intensive care unit (ICU) during the first three waves of the COVID-19 pandemic and to study associations between dexamethasone (DXM) use and development of VAP.

Methods: In an observational single-center study patients were retrospectively screened for VAP including causative pathogens, use of DXM and commonly used antibiotics. Diagnosis of VAP required invasive mechanical ventilation (IMV) >48 h with presence of a new bacterial agent and clinical signs of infection. For analysis, common descriptive statistics were applied. Cox proportional hazards models were used to analyze the association between DXM use and VAP.

Results: VAP was detected in 53/119 (44.5%) mechanically ventilated patients across all three COVID-19 waves. Median length of IMV for VAP patients was 24 [15-41] days, and 3 out of 4 were males. VAP was most prevalent (47.0%) during the second wave. Common pathogens included Klebsiella pneumoniae (24.5%), Enterobacter aerogenes (17.0%) and Pseudomonas aeruginosa (13.2%), Staphylococcus aureus (13.2%), and Escherichia coli (13.2%). A change from Gram-negative bacteria only to a combination of Gram-positive and Gram-negative bacteria was observed in the second wave compared to first. Use of DXM was not associated with VAP (adjusted hazard ratio 1.63 95% CI: 0.84-3.17).

Conclusion: The prevalence of VAP was high across all three COVID-19 waves and showed a different distribution of pathogens between the first and second wave. Use of DXM was not associated with VAP development. Further and larger studies are needed to understand the risk factors associated with VAP in patients with COVID-19.