Comparative analysis of predictors of failure for high-flow nasal cannula in bronchiolitis

Objective: To assess a comparative analysis of the ROX index,
Wood-Downes-Ferrés score (WDF), p-ROXI, and the SpO2/FiO2 ratio as
predictors of high-flow nasal cannula (HFNC) failure in children
hospitalized for bronchiolitis. Methods: Data were extracted from
the clinical trial “Comparison between HFNC and NIV in children with acute
respiratory failure caused by bronchiolitis” conducted at a tertiary
Brazilian hospital (Emergency Department and PICU). The inclusion criteria
were children under 2 years of age admitted for bronchiolitis who
developed mild to moderate respiratory distress and were eligible for HFNC
therapy. Performance was determined by ROC and AUC metrics to define the
best sensitivity and specificity for each variable. Children were
evaluated at 0 h, 2 h, 6 h, 12 h, 24 h, 48 h, 72 h and 96 h after HFNC
therapy initiation. Results: A total of 126 patients were
recruited for this analysis. The median age was 3 months. Ninety-one
percent of the patients had an identified viral agent, with RSV being the
most common (65%). Twenty-three percent (29/126) of patients experienced
failed HFNC therapy and required mechanical ventilation. The best cutoff
points at 12 hours were 4.5 for WDF (AUC=0.83, 0.74-0.92), 8.8 for ROX
(AUC=0.7, 0.54-0.84), 1.45 for p-ROXI (AUC=0.56, 0.38-0-74), and 269 for
SpO2/FiO2 (AUC=0.64, 0.48-0.74). The scores and indices were also
correlated with the PICU and hospital LOS. Conclusions: The ROX index and
WDF were the most accurate scores for assessing HFNC failure considering
12-hour cutoff points. Trial registration number: U1111-1262-1740;
RBR-104z966s. Date of registration: 03/01/2023.