Factors associated with treatment failure of high-flow nasal cannula among children with bronchiolitis: a single-centre retrospective study

Objectives: Bronchiolitis is the most common viral lower respiratory tract infection in children under age 2 for which high-flow nasal cannula (HFNC) is increasingly used. Understanding factors associated with HFNC failure is important to identify patients at risk for respiratory deterioration. The objective of this study was to evaluate patient characteristics associated with HFNC failure in bronchiolitis. Methods: A retrospective review of patients aged 0 to 24 months, with bronchiolitis who received HFNC within a single tertiary paediatric intensive care unit, between January 2014 and December 2018 was conducted. HFNC treatment failure was defined as escalation to non-invasive positive pressure or invasive mechanical ventilation. Multivariable regression analysis was used to identify demographic, clinical, and biochemical parameters associated with HFNC failure. Results: Two hundred eight patients met inclusion criteria, of which 61 (29.33%) failed HFNC. Risk factors for HFNC failure included younger age (odds ratio [OR] 1.12; 95% confidence interval [CI] 1.03, 1.23; P=0.011) and a Modified Tal score greater than 5 at 4 hours of HFNC therapy (OR 2.81; 95% CI 1.04, 7.64; P=0.042). Duration of HFNC in hours was protective (OR 0.94; 95% CI 0.92, 0.96; P<0.001), such that deterioration is less likely once patients have remained stable on HFNC for a prolonged time. Conclusion: This is the first study exploring predictors of HFNC failure among Canadian children with bronchiolitis. Patient age, HFNC duration, and Modified Tal score were associated with HFNC failure. These factors should be considered when initiating HFNC for bronchiolitis to identify patients at risk for deterioration.