Epidemiology of microbiological findings in the lower respiratory tract in mechanically ventilated patients with and without inhalation injury.

BACKGROUND

In mechanically ventilated burn patients, inhalation injury may increase the risk of lower respiratory tract colonization or infection with potentially pathogenic microorganisms and worsen in-hospital outcomes.

OBJECTIVE

We investigated the occurrence of potentially pathogenic microorganisms in lower respiratory tract samples and their association with in-hospital mortality in mechanically ventilated patients with and without inhalation injury.

METHODS

We conducted a retrospective observational study at a tertiary burn center (2007-2022) including patients who required mechanical ventilation for ≥2 days and sustained cutaneous burns and/or inhalation injury; clinical and microbiological data were extracted from medical records.

RESULTS

Among 311 mechanically ventilated patients, 305 had cutaneous burns, 168 had inhalation injury, and 180 had lower respiratory tract samples positive for potentially pathogenic microorganisms. Gram-positive bacteria predominated early during hospitalization, while gram-negative bacteria and fungi became more frequent over time. Patients with inhalation injury showed shorter time to in-hospital death than those without inhalation injury (mean 32 vs 64 days), regardless of total body surface area burned. Detection of extended-spectrum beta-lactamase-producing organisms was associated with higher mortality risk and substantially longer hospital stays.

CONCLUSION

Inhalation injury was associated with a higher likelihood of lower respiratory tract positivity for potentially pathogenic microorganisms and with increased in-hospital mortality in mechanically ventilated patients.