(1210) The Respiratory Oxygenation (ROX) Index to Predict Negative-Pressure Ventilation Treatment Failure

Introduction: Bronchiolitis, defined as an acute lower viral respiratory tract infection affecting children less than 2 years of age, is the leading cause of acute respiratory failure in this age group. Negative pressure ventilation (NPV) with high-flow nasal cannula (HFNC) is used in some centers for the escalation of non-invasive respiratory support in children with bronchiolitis. Evidence has shown an association with the decrease in oxygen requirements and improved Pco2 clearance within hours of initiation, thus decreasing the need for mechanical ventilation. The Respiratory Oxygenation (ROX) Index has shown good specificity in predicting failure with HFNC in adult and pediatric patients thereby mitigating the risks of delayed intervention with mechanical ventilation. This novel study investigates the use of the ROX Index, as well as modified indices (ROX-M and ROX-HR) for pediatric patients, in early prediction of failure with negative pressure ventilation (NPV).

Methods: A single-center retrospective study including children under 2 years of age admitted to the pediatric intensive care unit (PICU) with acute respiratory failure secondary to bronchiolitis over a 4-year study period. Eligible patients identified by ICD-10 codes: J21.9, J21.0, J21.1, J96.0, J96.1. S/F Ratio and ROX Indices were calculated at initiation and hour 2, 4, 6, 12,18, and 24.

Results: Of 1,151 eligible patients, 259 children were treated with NPV. Of those subjects, 53 (20%) failed treatment with NPV and required escalation to mechanical ventilation. Mean ROX Index estimates at time points of interest for the total study population were greater than 5. Similarly, mean ROX-HR and ROX-M indices are greater than 200 and 3, respectively. The ROX Index and modified indices showed moderate to strong correlation with the S/F Ratio at each hour of interest (Pearson’s r= 0.346 to 0.702, p < 0.001).

Conclusions: Although preliminary, this data is consistent with previous ROX Index thresholds for predicting treatment failure of non-invasive respiratory support. The application of the ROX Index and the pediatric modified indices during negative pressure ventilation management may help identify those patients that are likely to fail treatment, leading to earlier escalation of respiratory support.