Clinical Predictors of High-Flow Nasal Cannula Failure in Children with Acute Respiratory Illness: A Single-Center Experience.

High-flow nasal cannula (HFNC) therapy is increasingly used for managing pediatric respiratory distress; however, early identification of children at risk of treatment failure remains challenging. This retrospective observational study evaluated clinical predictors of HFNC failure among children aged 1 mo to 12 y admitted with moderate-to-severe respiratory illness at a tertiary care center between April and June 2025. Fifty children received HFNC therapy, of whom 44 (88%) had successful outcomes, while six (12%) required invasive mechanical ventilation, among these two died. HFNC failure was significantly associated with a Respiratory Severity Score (RSS) ≥10, admission oxygen saturation (SpO2) <85%, congenital heart disease, severe acute malnutrition, and anemia. The combination of RSS ≥10 and SpO2 <85% demonstrated the highest predictive accuracy for HFNC failure. Owing to the limited number of failure events, only univariate analyses were performed. Early bedside assessment using RSS and SpO2 may facilitate timely escalation of respiratory support and improve clinical decision-making in resource-limited pediatric settings.