High-Flow Nasal Cannula

HFNC is a respiratory-support therapy, not simply a higher setting on a conventional nasal cannula. In adults with acute hypoxemic respiratory failure, it is generally preferred over conventional oxygen when the patient needs more reliable oxygen delivery and relief of respiratory effort. It can also support selected patients after extubation or during preparation for intubation. The bedside question is not whether the pulse oximeter improves for a few minutes. It is whether oxygenation improves while respiratory rate, work of breathing, gas exchange, mental status, and hemodynamics recover. HFNC can buy time, but persisting with it in a non-responder can delay a necessary airway intervention. In Canada, initiation, titration, and weaning follow provincial or territorial requirements and institutional protocol, commonly in collaboration with a registered respiratory therapist and the prescribing team. Adult settings must not be transposed to children; pediatric flow and oxygen targets require an age- and weight-based pathway.