Bronchiolitis is the most common viral lower respiratory tract infection in children under two years of age and is the leading cause of hospital admission for children under the age of one year. Respiratory support for bronchiolitis with high flow nasal cannula (HFNC) is increasingly being used outside of critical care areas and in community hospitals. It is important to understand the patient factors associated with HFNC treatment failure in order to identify which patients are at higher risk for requiring escalation of respiratory support and transfer to a pediatric critical care centre.
The primary objective of this study was to evaluate the patient characteristics that are associated with HFNC treatment failure in bronchiolitis.
We completed a retrospective review of patients under 24 months of age with a clinical diagnosis of bronchiolitis admitted to a single tertiary level children’s hospital for supportive management with HFNC between January 2014 and December 2018. Patients who were mechanically ventilated or on non-invasive positive pressure ventilation prior to the initiation of HFNC during their hospital stay were excluded. HFNC treatment failure was the primary endpoint of the study, with treatment failure defined as escalation to non-invasive positive pressure or invasive mechanical ventilation. Multivariable logistic regression analysis was used to identify the patient demographic, clinical, and biochemical parameters associated with HFNC failure.
Four hundred and thirty-five patient charts were identified, of which 208 patients met inclusion criteria for the study. Of these patients, 61 (29%) were classified as HFNC treatment failures. The likelihood of failing HFNC support was reduced with older age (OR 0.89; 95% CI 0.81, 0.97; p= 0.011) and greater time spent on HFNC (OR 0.94; 95% CI 0.92, 0.96; p<0.001). Patients with a Modified Tal score greater than 5 at 4 hours of HFNC treatment had a greater likelihood of failing HFNC support (OR 2.81; 95% CI 1.04, 7.64; p= 0.042).
This was the first study to examine predictors of HFNC failure among Canadian children with bronchiolitis. We found that patient age, time spent on HFNC, and severity of bronchiolitis as defined using a Modified Tal score were associated with HFNC failure. These patient factors should be considered when initiating HFNC for bronchiolitis, and may identify patients at risk for escalation of respiratory support, warranting earlier referral to pediatric critical care centres.