Assessment of high-flow nasal cannula efficacy in humidification of infant airways: A computational fluid dynamics approach.

Introduction: High-flow nasal cannula therapy has garnered significant interest for managing pathologies affecting infants' airways, particularly for humidifying areas inaccessible to local treatments. This therapy promotes mucosal healing during the postoperative period. However, further data are needed to optimize the use of these devices. In vivo measurement of pediatric airway humidification presents a challenge; thus, this study aimed to investigate the airflow dynamics and humidification effects of high-flow nasal cannulas on an infant's airway using computational fluid dynamics.

Methods: Two detailed models of an infant's upper airway were reconstructed from CT scans, with high-flow nasal cannula devices inserted at the nasal inlets. The airflow was analyzed, and wall humidification was modeled using a film-fluid approach.

Results: Air velocities and pressure were very high at the airway inlet but decreased rapidly towards the nasopharynx. Maximum relative humidity-close to 100%-was achieved in the nasopharynx. Fluid film development along the airway was heterogeneous, with condensation primarily occurring in the nasal vestibule and larynx.

Conclusion: This study provides comprehensive models of airway humidification, which pave the way for future studies to assess the impact of surgical interventions on humidification and drug deposition directly at operative sites, such as the nasopharynx or larynx, in infants.