When used conservatively, high-flow warm humidified oxygen (HFWHO) improves outcomes for infants admitted to the hospital for moderate bronchiolitis after standard low-flow cannula oxygen therapy fails, according to results of a comparative trial recently published in The Lancet.1
In an investigation led by Elizabeth Kepreotes, MD, of John Hunter Research Hospital, Newcastle in New South Wales, Australia, from July 2012 to May 2016, 202 children under the age of 24 months diagnosed with bronchiolitis were randomly assigned (101 patients in each group) to either HFWHO or standard 100% cold oxygen therapy on admission. Weaning started after 3 hours and nasopharyngeal aspirate samples were taken from all participants. At that time, 6 patients had no detectable virus (3% in each group), and the most commonly detected viruses were respiratory syncytial virus (RSV) in 62 patients (61%) of patients given HFWHO compared with 54 children (53%) given standard therapy, and rhinovirus in 55 (54%) and 40 patients (40%), respectively.
The primary outcome of time to weaning did not differ significantly between groups. The investigators were not able to calculate the secondary end point of time to treatment failure as it was never reached by 50% of the population, and so they substituted 24-hour survival without treatment failure as the secondary end point. By this measure, HFWHO was superior to standard therapy; 90% vs 60% of patients were free of treatment failure, with a 95% CI.
Cost analysis indicated initially that standard therapy was significantly more economical at $A 5 per week per infant compared to $A 80 per week for the equipment required for HFWHO. This was significantly countered, however, by total cost savings to HFWHO in reducing the need for intensive care unit (ICU) stays and additional resources, due to 19 fewer treatment failures than with standard therapy.
Adverse events were minimal and not serious, with 2 occurring in each treatment group that were the result of caregiver errors in hooking up the equipment. In addition, the investigators reported 13 violations of weaning protocols during the trial, pointing to the need for greater attention to administration. “It is important to think about oxygen as being a drug and use the same rigor as is needed for medication administration and dosing,” Dr Kepreotes told Infectious Disease Advisor. “Everyone who is involved with oxygen administration, including families, needs education about its safe use, the required equipment checks, and patient observations. HFWHO looks more dramatic than standard therapy with a warming base and water for humidification, but regardless of the mode of oxygen delivery, hourly equipment checks and safe standardized procedures for use and weaning are required.”
The results of this study pointed to clinical benefits to HFWHO over standard therapy, at lower total costs, although when standard therapy works, it is significantly more cost-effective. “For the majority, starting on standard therapy and then changing over to HFWHO if it is not sufficiently supportive is the most economical approach.” Dr Kepreotes said. “If you could predict the children who were going to deteriorate and fail to be supported by standard therapy, you would start them on HFWHO. Some risk factors such as young age, prematurity, comorbidities have been identified in other studies, but some children without these factors go on to develop severe infections requiring additional respiratory support.”
This is the first randomized clinical trial to investigate comparative measures for oxygen therapy in bronchiolitis in young children, Dr Kepreotes pointed out, suggesting that more clinical trials are needed to add to the evidence base for pediatric use of HFWHO RCT.
Kepreotes E, Whitehead B, Attia J, et al. High-flow warm humidified oxygen versus standard low-flow nasal cannula oxygen for moderate bronchiolitis (HFWHO RCT): an open, phase 4, randomised controlled trial. Lancet. 2017;389:930-939. doi: 10.1016/S0140-6736(17)30061-2