High-flow nasal cannula for lower respiratory infections in children under 2 years: a systematic review of indications

Background High-flow nasal cannula (HFNC) therapy is increasingly used for lower respiratory tract infections (LRTIs) in infants and young children, but recommendations vary, and standardised practice is lacking. Objective To systematically review national or international guidelines on HFNC use in children aged 1–23 months with LRTIs, focusing on initiation, administration, monitoring, discontinuation and feeding. Methods We searched MEDLINE, EMBASE, CINAHL, Web of Science and professional society websites (2014–2025) for guidelines on HFNC use in this age group. Four reviewers independently screened, extracted data and assessed quality with the AGREE II tool. Interguideline concordance was calculated for all guidelines and separately for those addressing bronchiolitis and for evidence-based versus consensus-based guidelines. Recommendations were synthesised narratively. Results Fifteen guidelines were included, including nine bronchiolitis guidelines. All addressed HFNC initiation, with low oxygen saturation (73%) and respiratory distress (47%) as common indications. Initial flow recommendations varied; 2L/kg/min was most frequent (57%), and all bronchiolitis guidelines reporting it advised weight-based settings. Only two guidelines included weaning or discontinuation protocols, and seven addressed failure criteria. Monitoring typically included pulse oximetry and clinical observation; pulse oximetry was endorsed by all bronchiolitis guidelines that reported it (8/9). Enteral feeding was supported by all reporting guidelines (6/15). Guideline quality was moderate to high, though applicability and updating were frequent gaps. Conclusions HFNC guideline recommendations for young children with LRTIs remain inconsistent, particularly regarding weaning, failure criteria and procedural details. Regular updates and greater standardisation are needed to improve care and optimise resource use. PROSPERO registration number CRD42024622544