Impact of initial high flow nasal cannula flow rates on clinical outcomes in children with bronchiolitis

Purpose Our aim was to evaluate the impact of the initial high flow nasal cannula (HFNC) flow rate on clinical outcomes in children with bronchiolitis. Methods This secondary analysis of retrospective data included children <2 years who required HFNC for bronchiolitis between 10/01/2018–04/20/2019, and following implementation of a revised institutional bronchiolitis pathway between 10/01/2021–04/30/2022. The new pathway recommended weight‐based initiation of HFNC at 1.5–2 L/kg/min. We evaluated the effect of low (<1.0 L/kg/min), medium (1–1.5 L/kg/min) and high (>1.5 L/kg/min) HFNC flow rates on need for positive pressure ventilation (PPV), intensive care unit (ICU) transfer, HFNC treatment time, and hospital length of stay (LOS). Results The majority of the 885 included children had low initial flow rates (low [ n = 450, 50.8%], medium [ n = 332, 37.5%] and high [ n = 103, 11.7%]). There were no significant differences in PPV (high: 7.8% vs. medium: 9.3% vs. low: 8.2%, p = 0.8) or ICU transfers (high: 4.9% vs. medium: 6.0% vs. low: 3.8%, p = 0.3). The low flow group had a significantly longer median HFNC treatment time (High: 29 [18, 45] vs. medium: 29 [16, 50] vs. low: 39 [25, 63], p < .001) and hospital LOS (High: 41 [27, 59] vs. medium: 42 [29, 66] vs. low: 50 (39, 75), p < .001). Logistic and linear regression models did not demonstrate any associations between HFNC flow rates and PPV or hospital LOS. Conclusions Initial HFNC flow rates were not associated with significant changes in clinical outcomes in children in children with bronchiolitis.