[High flow oxygen therapy with nasal cannula: use and applications in respiratory failure in internal medicine.]

High-flow nasal cannula (HFNC) are an oxygen therapy device developed in the last years for the treatment of patients with acute or acute on chronic hypoxemic respiratory failure with different etiology and severity (including covid-19 pneumonia). HFNC combine the possibility of delivering high flows of gases, actively humidified and heated, with the use of a comfortable nasal interface, resulting generally well tolerated by most patients. In light of these characteristics, together with the simplicity of use and versatility, they have spread not only in intensive and semi-intensive care units but also in general medical ward in which they can play an important role in the treatment of elderly, frail patients with comorbidity where other more aggressive and invasive methods of ventilations are not indicated or not practicable.