Fire simulator exposure alters the innate epithelial response and inflammatory status in the airways of firefighters

Background: Firefighters are often exposed to high temperatures and by-products of combustion, which can compromise their health. We aimed to evaluate the effect of fire exposure in fire simulators on the airways of firefighters at different time-points. Methodology: Thirty-seven male firefighters exposed to fire simulators were evaluated in three phases: pre-exposure, at the end of the first week, and 4 weeks after. Pulmonary function by spirometry, nasal mucociliary clearance; peripheral oxygen saturation, inflammatory markers in the nasal lavage and CC16 in the sputum, nasal obstruction, and quality of life (using the questionnaires NOSE and SNOT-22) were assessed. Results: Higher levels of IL-8, IL-10, and exhaled carbon monoxide were found more in phase 2 than in phase 1. Higher CC16 levels and lower peripheral oxygen saturation were observed in phase 3 as compared to phase 1. Lower levels of IL-2 and peripheral oxygen saturation were found in phase 3 than in phase 2. Higher nasal mucociliary clearance, as well as the worst quality of life and nasal obstruction, were observed in phases 2 and 3 as compared to phase 1. Conclusions: The firefighters' exposures to high temperatures and by-products of combustion in the fire simulators elicit an inflammatory process in the airways with impairment in the innate epithelial response of the upper airway lining. Furthermore, changes in O2 transport affected the professionals' quality of life negatively.