Table 2

Inclusion and exclusion criteria

Inclusion criteriaExclusion criteria

  • Children aged 1–4 years plus 364 days presenting with AHRF

  • and require hospital admission despite initial assessment and therapy

  • and an ongoing oxygen requirement (SpO2 <90/92%* in room air, dependent on hospital policy)

  • and have a persistent tachypnoea of ≥35 breath/min for ≥10 mins at the time of randomisation

  • Oxygen requirement and therapy in the emergency department existed for longer than 4 hours prior to inclusion (excludes oxygen given in ambulance or other hospital)

  • Previous use of high-flow during this illness episode

  • Upper airway obstruction

  • Craniofacial malformations

  • Critically ill infants requiring immediate higher level of respiratory support that is, non-invasive or invasive ventilation, low level of consciousness OR

  • Critically ill with immediate need for intubation or non-invasive ventilation with the need of closer observation in ICU

  • Basal skull fracture

  • Trauma

  • Cyanotic heart disease (eg, blue baby, expected normal saturation in room air <90/92%)

  • Home oxygen therapy

  • Palliative care

  • Cystic fibrosis

  • Oncology

  • Child protection patients

  • AHRF, acute hypoxaemic respiratory failure; ICU, intensive care unit; SpO2, oxygen saturation.