[High nasal flow, the solution for hypoxaemia?]

High nasal flow (HNF) is a new method to deliver a high flow of oxygen (up to 60 l/min) through a nasal cannula. The inspiratory oxygen fraction can be set in a range from 21 to 100%. The inspired air is adjusted to body temperature and saturation. Many patients find it more comfortable than a conventional oxygen mask. In spite of these advantages, the mechanism of action is not completely understood and empirical evidence for its use is limited. This article provides a simplified explanation of variable positive airway pressure generation by HNF and related flushing of the anatomic dead space. Based on a short discussion of recent studies, it is concluded that HNF is a promising technique but that questions remain about the indications for use in clinical practice.