Epidemiology, risk factors and prognosis of ventilator-associated pneumonia during severe COVID-19: Multicenter observational study across 149 European Intensive Care Units

Abstract

Background: COVID-19 patients requiring mechanical ventilation are particularly at risk of developing ventilator-associated pneumonia (VAP). Risk factors and the prognostic impact of developing VAP during critical COVID-19 have not been fully documented.

Methods: Patients invasively ventilated for at least 48 h from the prospective multicentre COVID-ICU database were included in the analyses. Cause-specific Cox regression models were used to determine factors associated with the occurrence of VAP. Cox-regression multivariable models were used to determine VAP prognosis. Risk factors and the prognostic impact of early vs. late VAP, and Pseudomonas-related vs. non-Pseudomonas-related VAP were also determined.

Main findings: 3388 patients were analysed (63 [55-70] years, 75.8% males). VAP occurred in 1523/3388 (45.5%) patients after 7 [5-9] days of ventilation. Identified bacteria were mainly Enterobacteriaceae followed by Staphylococcus aureus and Pseudomonas aeruginosa. VAP risk factors were male gender (Hazard Ratio (HR) 1.26, 95% Confidence Interval [1.09-1.46]), concomitant bacterial pneumonia at ICU admission (HR 1.36 [1.10-1.67]), PaO₂/FiO₂ ratio at intubation (HR 0.99 [0.98-0.99] per 10 mmHg increase), neuromuscular-blocking agents (HR 0.89 [0.76-0.998]), and corticosteroids (HR 1.27 [1.09-1.47]). VAP was associated with 90-mortality (HR 1.34 [1.16-1.55]), predominantly due to late VAP (HR 1.51 [1.26-1.81]). The impact of Pseudomonas-related and non-Pseudomonas-related VAP on mortality was similar.

Conclusion: VAP affected almost half of mechanically ventilated COVID-19 patients. Several risk factors have been identified, among which modifiable risk factors deserve further investigation. VAP had a specific negative impact on 90-day mortality, particularly when it occurred between the end of the first week and the third week of ventilation.

Keywords: COVID-19; Intensive Care Unit; Invasive mechanical ventilation; Mortality; Risk factors; Ventilator-associated pneumonia.