Humidification of inspired gas is important for patients receiving respiratory support. High-flow nasal cannula (HFNC) effectively provides temperature and humidity-controlled gas to the airway. We hypothesized that various levels of gas humidification would have differential effects on airway epithelial monolayers. Calu-3 monolayers were placed in environmental chambers at 37°C with relative humidity (RH) < 20% (dry), 69% (noninterventional comparator), and >90% (HFNC) for 4 and 8 hours with 10 L/min of room air. At 4 and 8 hours, cell viability and transepithelial resistance measurements were performed, apical surface fluid was collected and assayed for indices of cell inflammation and function, and cells were harvested for histology (n=6/condition). Transepithelial resistance and cell viability decreased over time (P<0.001) between HFNC and dry groups (P<0.001). Total protein secretion increased at 8 hours in the dry group (P<0.001). Secretion of interleukin (IL)-6 and IL-8 in the dry group was greater than the other groups at 8 hours (P<0.001). Histological analysis showed increasing injury over time for the dry group. These data demonstrate that exposure to low humidity results in reduced epithelial cell function and increased inflammation.
Research for the Influence of Inlet Gas Humidification on PEMFC
