Micro- and nanoparticle transport and deposition in a realistic neonatal and infant nasal upper airway

The human nasal cavity develops from birth with size anatomical changes. This study aims to evaluate the flow parameters and particle deposition parameters. Neonatal and infant nasal cavities are developed using MIMICS 21.0, and the flow is evaluated by ANSYS 2021 R2 using CFD to evaluate velocity, pressure, micro- and nanoparticle depositions under sedentary breathing conditions. Neonatal nasal valve velocity was recorded 3.5 times higher compared to the infant for 1.8 LPM and 2.7 times for 3 LPM. Neonatal vestibular depositions up to 10 µm were 6.6%, which increased to 76% for 60 µm for 1.8 LPM and increased to 21.3% for 10 µm and 79% for 60 µm for 1.8 LPM. The neonatal nasal valve showed maximum depositions of around 35% for 20 µm for both flow rates. Maximum depositions of nanoparticles are in the mid-nasal region. Infant nasal cavities deposit around 1% to 2% for nanoparticles below 20 nm for both flow rates. Neonatal overall microparticle depositions doubled with an increase in flow rate up to 10 µm. The overall deposition efficiency of nanoparticles increases 1.5 times with increasing flow rate. This study will help with the medical administration of aerosol-based medications in the patient and age-specific nasal cavity.