COMMENTARY

Does High-Flow Cannula Oxygen Improve Bronchiolitis Outcomes?

William T. Basco, Jr., MD, MS

Disclosures

June 06, 2018

High-Flow Versus Standard Nasal Cannula Oxygen in Bronchiolitis

Current guidelines recommend only supportive care such as supplemental oxygen and hydration for infants with bronchiolitis.[1] A multicenter, randomized trial[2] evaluated whether high-flow nasal cannula oxygen therapy would also be beneficial in these cases. The study was conducted in Australia and New Zealand during a time when high-flow nasal cannula oxygen was already becoming the standard of care at the study institutions. All study children were less than 1 year old and required supplemental oxygen for bronchiolitis, with a target oxygen saturation of 92% or 94% depending on the individual hospital's policy. The study excluded infants who needed immediate respiratory intervention, were transferred to intensive care, or had other chronic conditions that might influence the outcome.

The infants in the intervention group received humidified high-flow oxygen at 2 L/kg of body weight/min. It was discontinued when the infants had gone 4 hours on room air (an inspired oxygen concentration of 21%). The infants who received standard therapy received supplemental oxygen by standard nasal cannula at a rate of up to 2 L/min to reach the same target oxygen saturation.

The primary outcome was treatment failure that required escalation of care. Treatment failure could be documented by any of the following:

  • A lack of improvement in heart rate compared with the admission heart rate;

  • A lack of improvement in respiratory rate;

  • A requirement for oxygen concentration >40% to maintain target pulse oxygen saturations;

  • A nasal cannula flow rate >2L/kg/min in the standard therapy group; or

  • Triggering of an early warning signal that required an assessment to determine the need for escalation of care.

Study Findings

More than 1400 infants (mean age, 6 months) were enrolled between 2013 and 2016, and more than 1400 infants were included in the analysis. More than 60% of each group were boys.

With respect to the primary outcome, treatment failure occurred in 12% of the children in the high-flow group compared with 23% of the children in the standard therapy group (risk difference of -11 percentage points). The time to treatment failure did not differ between the two groups.

Secondary analyses that included history of prematurity, previous hospitalization, or infection with respiratory syncytial virus did not demonstrate a difference in the primary outcome. Similarly, no differences were found in the secondary outcomes (duration of hospital stay, duration of oxygen therapy, or frequency of admission to intensive care). For example, the mean length of stay for those in the standard therapy group was 2.94 days compared with 3.12 days in the high-flow group, a nonsignificant difference. A transfer to intensive care was required for 9% of the standard group compared with 12% of the high-flow group (also not statistically different).

The investigators concluded that infants with bronchiolitis treated with high-flow nasal cannula oxygen were less likely to require escalation of care compared with infants treated with traditional nasal cannula oxygen.

Viewpoint

It seems that every time I review a bronchiolitis trial, I begin with similar comments: In about 20 years of practice looking for the magic bullet for bronchiolitis, it's been hard to find much beyond supportive care! Although the primary outcome was better among the intervention group, I'm sure that individual practitioners and hospitals will want to consider whether the lack of difference in hospital length of stay or intensive care admission is worth changing oxygen delivery systems for hospitals already not routinely using high-flow oxygen. It would also be nice to see this study replicated.

For now, I suspect that people will use the study both ways—both to support use of high-flow oxygen therapy for bronchiolitis and to say that maybe it's not quite ready for universal adoption.

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