High-flow nasal oxygen [HFNO] therapy is a focus of growing attention as an alternative to standard oxygen therapy. By providing warmed and humidified gas, HFNO allows the delivery of higher flow rates [of up to 60 L/min] via nasal cannula devices, with Fraction of inspired oxygen (FiO2) values of nearly 100%. Physiological benefits of HFNO consist of higher and constant FiO2 values, decreased work of breathing, nasopharyngeal washout leading to improved breathing-effort efficiency, and higher positive airway pressures associated with better lung recruitment.