Despite living in an era of evidence-based medicine and austerity, where every health dollar must be justified, the use of humidified high-flow nasal cannula oxygen (HFNC) in children with bronchiolitis has become increasingly prevalent, 1 with limited evidence to substantiate its clinical benefit or economic worth. Current National Institute for Health and Care Excellence (NICE 2015) guidelines for bronchiolitis state that ‘the use of this medical device is becoming widespread without demonstration of additional efficacy’. Recent studies by Kepreotes et al 2 and Riese et al 3 have shown that the use of ward-based HFNC in children with bronchiolitis did not reduce the hospital length of stay (LOS) or rate of admission to the paediatric intensive care unit (PICU), when compared with standard low-flow oxygen therapy.

We undertook a retrospective pre–post cohort study of infants aged≤ 12 months with bronchiolitis who were admitted to a tertiary Australian paediatric hospital. A period of 12 months prior to the widespread use of HFNC (January–December 2012) was compared with a 12-month period following the establishment of HFNC as a ward-based treatment escalation modality for children with bronchiolitis (January–December 2015). The commencement of HFNC was considered for clinical signs of persistent or worsening hypoxia and respiratory distress despite standard flow oxygen at the discretion of the treating clinician; objective measures of