High-Flow Nasal Cannula for Peri-Intubation Oxygenation in Pediatric Rapid Sequence Intubation: A Narrative Best-Evidence Review

Pediatric rapid sequence intubation (RSI) carries a high risk of peri-intubation hypoxemia because children have limited oxygen reserve and desaturate rapidly during apnea. High flow nasal cannula (HFNC) is an appealing adjunct because it can deliver high, humidified flows that reduce room air entrainment and support a more stable upper airway oxygen concentration, with modest flow and leak-dependent distending pressure and upper airway dead space washout. Across pediatric perioperative and sedation studies and in acute care cohorts, the most consistent signal is improved oxygenation reliability, with fewer or less severe desaturation events and fewer rescue interventions, rather than a predictable extension of safe apnea time, which remains variable across settings. Adult peri-intubation trials provide a comparator context and reinforce that the observed benefit depends on baseline hypoxemia and the comparator strategy, often favoring NIV in severe hypoxemia, limiting direct generalization to children. Pediatric RSI-specific randomized trials are needed with standardized flow protocols and clinically meaningful endpoints, including severe desaturation rates, nadir SpO₂, time spent below clinically relevant thresholds, need for rescue ventilation or interrupted laryngoscopy, first pass success, and adverse events.