1 Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
2 Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
3 Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
4 Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
5 Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
6 Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
7 Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
8 Department of Perioperative Medicine and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
Bakgrund: Ventilator-associated lower respiratory tract infections (VA-LRTI) are associated with prolonged length of stay and increased mortality. We aimed to investigate the incidence of bacterial VA-LRTI among mechanically ventilated COVID-19 patients and compare these findings to non-COVID-19 cohorts throughout the first and second wave of the pandemic.
Metod: Retrospective cohort study of all patients ≥18 years treated with mechanical ventilation year 2011-2020 in Karolinska University Hospital, Stockholm, Sweden.
Resultat: The cohort consisted of 20,223 ICU episodes (479 COVID-19), with a VA-LRTI incidence proportion of 30% (129/426) in COVID-19 and 18% (1,081/5,907) in non-COVID-19 among patients ventilated >48 hours. Median length of ventilator treatment for COVID-19 patients was 10 days (IQR 5-18), which was longer than for all other investigated specific diagnoses. The VA-LRTI incidence rate per 1,000 ventilator days at risk was 31 (95% CI 26-37) for COVID-19 and 34 (95% CI 32-36) for non-COVID-19. With COVID-19 as reference, adjusted subdistribution hazard ratios for VA-LRTI was 0.29-0.50 (95% CI, <1) for influenza, bacterial pneumonia, ARDS and severe sepsis, but 1.38 (95% CI 1.15-1.65) for specific non-infectious diagnoses. Compared to COVID-19 in the first wave of the pandemic, COVID-19 in the second wave had adjusted subdistribution hazard ratio of 1.98 (95% CI 1.28-3.05).
Slutsats: COVID-19 is associated with exceptionally long durations of mechanical ventilation treatment and high VA-LRTI incidence proportions. The incidence rate of VA-LRTI was compared to the pooled non-COVID-19 cohort however not increased in COVID-19. Significant differences in the incidence of VA-LRTI occurred between the first and second wave of the COVID-19 pandemic.