The A-B-C of high-flow nasal oxygen therapy use in a sick child.

Heated humidified high flow nasal cannula therapy (HFNC) is a relatively new method of oxygen delivery that came into vogue only a decade ago. The additional physiological benefits it provides make HFNC more than just a fancy oxygen delivery device. Theoretically, Continuous Positive Airway Pressure (CPAP) continues to be the gold standard therapy for moderate to severe respiratory disease. Practically, there are limitations to its use especially in older children outside of an intensive care setting. Initially, thought of as a step-down or step-up from or towards CPAP i.e. halfway between CPAP and nasal oxygen, HFNC has now overtaken CPAP as the respiratory support mechanism of choice. Paediatricians go straight from failure of HFNC to intubation without a trial of CPAP, or extubate children straight onto HFNC. Today, more than a decade later, high quality evidence (FIRST-ABC and Tramontane Trials) is finally available to guide its use. The article summarises the evidence base behind the clinical safety, efficacy, cost-effectiveness and practical use of HFNC in managing sick children on high dependency and intensive care units. We outline what HFNC therapy is, the respiratory physiology underlying its use, currently available devices, practicalities of how to select the flow rate and its role in current paediatric practice with clinical examples. [ABSTRACT FROM AUTHOR]