Heated High-Flow Nasal Cannula Therapy for Pediatric Obstructive Sleep Apnea: Physiology, Clinical Evidence, and Future Directions

Pediatric obstructive sleep apnea (OSA) is a common disorder associated with significant neurocognitive, behavioral, cardiovascular, and metabolic consequences. Although adenotonsillectomy remains first-line therapy for many children, residual OSA is common, particularly among those with obesity, craniofacial abnormalities, genetic syndromes, neuromuscular disease, or other forms of medical complexity. Continuous positive airway pressure (CPAP) is the standard non-surgical treatment; however, long-term effectiveness is frequently limited by poor tolerance and adherence. Heated high-flow nasal cannula (HFNC) therapy has emerged as a potential alternative for selected children with sleep-disordered breathing, particularly those who are unable to tolerate conventional positive airway pressure therapy. Unlike CPAP, HFNC delivers heated, humidified gas through an open nasal interface and may improve sleep-disordered breathing through a combination of flow-dependent positive airway pressure generation, dead-space washout, improved ventilatory efficiency, enhanced gas conditioning, and reductions in inspiratory resistance. However, the relative contribution of these mechanisms during sleep remains incompletely understood. Current clinical evidence consists primarily of physiological studies, retrospective cohorts, case series, and a limited number of prospective comparative studies. Collectively, these data suggest that HFNC can reduce obstructive respiratory events and improve oxygenation in selected pediatric populations, including children with persistent OSA, CPAP intolerance, medical complexity, and syndromic conditions. Nevertheless, important uncertainties remain regarding optimal patient selection, titration strategies, patient monitoring, long-term adherence and comparative effectiveness relative to CPAP. This review summarizes the physiological basis of HFNC therapy, critically appraises the current clinical evidence, discusses practical considerations related to adherence and implementation, and highlights key knowledge gaps and future research priorities. Overall, HFNC should be viewed as an alternative for selected children who cannot tolerate CPAP, rather than as a universal substitute for pressure-based therapy.