Comment on “Humidification with High-Flow Nasal Cannula and Airway Epithelial Cells: Caution, Still Learning from an Extremely Complex Environment”

We read with interest the paper by Chidekel et al. [1] on the effects of gas humidification with high-flow nasal cannula on cultured human airway epithelial cells. The authors used an “in vitro” method of bronchial epithelial cells culture and found increased total protein secretion and secretion of interleukins 6 and 8 after 8 hours of dry airflow compared with 69% and >90% of relative humidification groups as well as histological injury. The results raise the interest of this area focusing on the effects of humidification during spontaneous breathing and mechanical ventilation on epithelial cell structure, function and inflammatory response as pointed out by the authors [2, 3].We are aware that all several variables that may interfere in this physiological process cannot be completely reproducible and controlled by in vitromodels; however, some interesting aspects need attention.