Invasive mechanical ventilation is the cornerstone therapy for the acute respiratory distress syndrome (ARDS). However, because invasive mechanical ventilation is also associated with side effects and complications leading to substantial morbidity or even mortality, physicians have developed strategies to prevent endotracheal intubation. One of these strategies is non-invasive ventilation (NIV), which is the application of positive airway pressure via an external (non-invasive) interface. Recently, a newer non-invasive device has seen increasing use that allows delivery of heated and humidified high-flow gas at body temperature and saturation and flows up to 60 l/min with the fraction of inspired oxygen (FIO2) adjustable up to 100 % through a soft wide-bore nasal cannula (high-flow nasal cannula, HFNC).