This analysis was originally posted on REBEL EM here

Bronchiolitis is an acute inflammatory injury of the distal smaller airways, most commonly caused by viral infections.  There have been a host of medications studied in the treatment of bronchiolitis, including steroids, albuterol, epinephrine, and  inhaled hypertonic saline, with none proving to be effective in treatment.  Oxygen therapy via high-flow nasal cannula (HFNC) as opposed to standard nasal prongs provides some positive airway pressure which decreases work of breathing, improves oxygenation, and rates of intubation.  This trial evaluated early high-flow oxygen therapy vs standard oxygen therapy in infants with bronchiolitis and hypoxemia in both the emergency department and general pediatric ward settings.

Clinical Question

Does the use of HFNC in hypoxic infants with bronchiolitis reduce the need for escalation of care in comparison to standard oxygen therapy?


Infants <12 months of age with bronchiolitis and need for supplemental oxygen therapy



  • Heated & humidified high-flow oxygen at a rate of 2L/kg/min via Optiflow system
  • Fraction of inspired oxygen (FiO2) adjusted to obtain O2 sat levels between 92 – 98% or 94 – 98% at some of the treatment hospitals as they had a higher minimum oxygen threshold


Standard oxygen therapy

  • Supplemental oxygen through nasal cannula up to 2L/min
  • Maintain oxygen saturation level between 92 – 98% or 94 – 98% at some of the treatment hospitals as they had a higher minimum oxygen threshold


Primary: Escalation of care due to treatment failure (defined as meeting ≥3 out of 4 clinical criteria (Persistent tachycardia, Persistent tachypnea, Hypoxemia, Medical review triggered by a hospital early-warning tool)


  • Duration of hospital stay
  • Duration of oxygen therapy
  • Rates of transfer to a tertiary hospital
  • Rate of ICU admission
  • Rate of intubation
  • Rate of adverse events


Multicenter, randomized, controlled trial


  • Critically ill infants who had immediate need for respiratory support and ICU admission
  • Cyanotic heart disease
  • Basal skull fracture
  • Upper airway obstruction
  • Craniofacial malformation
  • Receiving oxygen therapy at home

Primary Results

  • 1472 infants included in the analysis
  • Baseline demographic characteristics were similar between groups
  • Approximately 18% of the included patient population had premature (<37weeks) birth
  • Non-study treatments/medications balanced between the two groups

Critical Results

  • Escalation of Care (Primary Outcome)
    • High-Flow Group: 12%
    • Standard Therapy Group: 23%
    • P <0.001
    • NNT = 9
    • Fragility Index = 51
  • Secondary outcomes
    • No significant differences in duration of hospital stay, duration of oxygen therapy or duration of ICU stay
    • Adverse Events: 1 infant in each group suffered a pneumothorax (<1% of infants) – no drainage needed in either case
  • 167 infants who had treatment failure with standard therapy
    • 102 (61%) had a response to high flow oxygen therapy


  • Protocol published previous to enrollment and completion of trial
  • Clinically important primary endpoint particularly in hospitals without pediatric ICUs
  • Investigators were unaware of trial outcome until the trial was completed
  • High-flow equipment for trial was donated by Fisher and Paykel Healthcare, who had no involvement in the design, analysis of data, or preparation of manuscript
  • Pre-specified subgroups were evaluated for heterogeneity of the studies results


  • Unblinded study – masking of the assigned treatment was not possible due to visually obvious differences between the two interventions. This may minimize the validity of the results of this paper due to placebo effect/bias or effect on physician decisions
  • Escalation rates were markedly higher in the hospitals that had an ICU on site in comparison to those that did not
  • Clinicians could escalate therapy if they were concerned for other clinical reasons, which is a subjective decision – this occurred in 34% of the patients who did not meet 3 out of the 4 criteria for escalation of care
  • The respiratory rate was quite a bit higher in the HFNC group vs Standard therapy group (62.6 +/- 15.2 vs 54.6 +/ 12.4), which could potentially mean that the HFNC group was a bit sicker and therefore the results of this study would underestimate the true benefit of HFNC vs Standard therapy

Other Issues

  • Interestingly at the sites that did not have an ICU, the treatment failure rate was significantly lower in the HFNC group vs standard therapy group: 7% vs 28% (NNT = 5) compared to sites that did have an ICU 14% vs 20% (NNT = 17)

Author's Conclusions

“Among infants with bronchiolitis who were treated outside an ICU, those who received high-flow oxygen therapy had significantly lower rates of escalation of care due to treatment failure than those in the group that received standard oxygen therapy.”

Our Conclusions

We agree with the authors conclusions. HFNC appears to decrease the rate of escalation of care in patients with bronchiolitis.

Potential Impact To Current Practice

There are few interventions that improve outcomes in patients with bronchiolitis. HFNC appears to be one of these. Clinicians should consider applying HFNC early on in the management of hypoxic infants with bronchiolitis.

Bottom Line

This large, well-done RCT demonstrates the superiority of HFNC to standard oxygen therapy in hypoxic infants with bronchiolitis with an NNT = 9.

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