Application of the TIDieR checklist to improve the HFNC use in bronchiolitis management

The use of High-Flow Nasal Cannula (HFNC) in children with bronchiolitis is globally increased in the last decade, despite the lack of evidence-based and universal guidelines to standardize their application in the clinical practice. In this systematic review, we aimed to analyse the completeness of previous studies on HFNC interventions in children with bronchiolitis using an adapted Template for Intervention Description and Replication (TIDieR) checklist. Randomized clinical trials (RCTs) and cohort studies on children younger than 2 years old with a diagnosis of bronchiolitis were included. We analysed manuscripts published between January 2010 and October 2023. An adapted TIDieR checklist based on 14 items about HFNC interventions was used to assess the completeness of the studies. A total sample of 67,324 patients was analysed in the 78 included manuscripts (21 RCTs and 57 cohort studies). Completeness of TIDieR checklist items ranged from 1% to 100%. The most reported items were related to the study rationale and the selection strategy (inclusion/exclusion criteria), identifying high quality of patients' selection in the included manuscripts. However, most of the studies did not provide separate indications for children with comorbidities. Only 23% of studies reported a complete definition and rates of treatment failure suggesting that this item needs more clarification in future studies. A minority of articles (40%) described the HFNC weaning procedures. Interestingly, most of the interventions took place in ICUs (61%), showing how, in the last decade, this location was the most cited for the use of HFNC in children with bronchiolitis.

Our results suggest complete reporting of our TIDieR checklist in future studies may improve the quality of the research on HFNC use in children with bronchiolitis. Our findings encourage researchers to clarify the personalization of treatment administration and to better define the criteria for treatment failure. The adoption of universal definitions in this field is needed to increase the results' comparability and create standardized protocols. Researchers may use the proposed TIDieR checklist to develop, conduct and report clinical research into HFNC and bronchiolitis as this may help to create a consensus for establishing an evidence-based protocol for HFNC.

• High-flow nasal cannula (HFNC) is a common device used in children with bronchiolitis in the presence of respiratory distress, after the failure of standard oxygen therapy. However, no evidence-based and standardized protocol for the use of this device is globally available.

• By using an adapted Template for Intervention Description and Replication (TIDieR) checklist to review previous studies on HFNC in bronchiolitis, we found a global heterogeneity in the description of interventions with some items of the checklist poorly reported. Thus, we suggest using our TIDieR checklist for developing, conducting and reporting clinical research into HFNC and bronchiolitis as this may help to create a consensus for establishing an evidence-based protocol for HFNC.