• Bronchiolitis
• Humidified High-flow Nasal Cannula Oxygen

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 respiratory failure were not a prerequisite to commencing HFNC. Admission data (age, LOS, oxygen support modality and PICU admission) for infants ≤12 months with bronchiolitis without significant preexisting comorbidities (eg, congenital cardiac disease, chronic lung disease and chronic neurological disorders) were obtained from electronic discharge summaries. Bronchiolitis was categorised as mild (no respiratory support), moderate (oxygen therapy in any combination of low-flow nasal prong oxygen, head-box oxygen or HFNC) or severe (requiring continuous positive airway pressure (CPAP) and/or invasive positive pressure ventilation (IPPV)) for subanalysis.

Six hundred and forty-five episodes of bronchiolitis fulfilling the inclusion criteria were identified (mean age 5.29 months±SD 3.38). A greater number of children were treated with HFNC in 2015 than in 2012 (59/344 (17.2%) versus 5/301 (1.7%) respectively, p<0.01). There was no difference in LOS between the two study periods for the entire cohort (2.06 vs 2.08 days, p=0.58) or within severity categories (table 1). There was no difference in the frequency of admissions to PICU (15/301, 5.0% vs 14/344, 4.1%, p=0.60) or use of CPAP (10/301, 3.3% vs 10/344, 2.9%, p=0.92) and IPPV (1/301, 0.3% vs 1/344, 0.3%, p=1.0).

The outcomes of our study support those of Kepreotes2 and Riese3 and prompt reflection: what are our actual treatment goals when using HFNC? Why has HFNC become so well established internationally without an adequate evidence base to guide appropriate use? Can we define a subset of children who are likely to benefit from HFNC compared with traditional rescue modalities? Is HFNC cost-effective compared with standard low-flow oxygen? We eagerly await the results of the Paediatric Acute Respiratory Intervention Study (PARIS) trial4 to help answer some of these critical questions and further define the role of HFNC in children with bronchiolitis.