The Science Journal of the American Association for Respiratory Care

2012 OPEN FORUM Abstracts

GROWTH OF NASAL-LARYNGEAL AIRWAYS IN CHILDREN AND THEIR IMPLICATIONS IN BREATHING AND INHALED AEROSOL DYNAMICS.

Jinxiang Xi1,2, JongWon Kim1, Yue Zhou4, Ariel Berlinski3; 1Systems Engineering, University of Arkansas at Little Rock, Little Rock, AR; 2Mechanical and Biomedical Engineering, Central Michigan University, Mount Pleasant, MI; 3Department of Pediatrics, University of Arkansas for Medical Science, Little Rock, AR; 4Aerosol and Respiratory Dosimetry Program, Lovelace Respiratory Research Institute, Albuquerque, NM

Background: Infants and children are more vulnerable to respiratory disorders than adults. Evaluating the health effects of environmental exposure in children requires a thorough understanding of transport and deposition of inhaled agents in their respiratory airways. As a human grows from birth to adulthood, both airway anatomy and breathing conditions vary, altering the aerodynamics and behaviors of inhaled aerosols. Method: In this study, we developed anatomical accurate computer models of the nasal-to-laryngeal airway based on CT/MRI scans of pediatric subjects at different ages, i.e., a 10-day-old newborn, a 7-month-old infant, a 3-year-old girl, and a 5-year-old boy. Dramatic growth was observed with age in both airway morphology and dimension. The airway dimension was further quantitatively compared based on different parameters (i.e., volume, cross-section area, and hydraulic diameter) and different sub-regions (i.e., nose, pharynx, and larynx). To investigate the breathing in children, a high-fidelity fluid-particle transport model was employed to simulate the multi-regime airflows and particle transport/deposition. Results and conclusions: For a same flow rate, breathing resistance persistently decreases with rising age. Specifically, ultrafine particles were evaluated under breathing conditions from sedentary to heavy activities. Results of this study indicate that the nasal airways at different ages, albeit differ significantly in morphology and dimension, do not significantly affect the total depositions for ultrafine aerosols. However, the deposition partitioning in the sub-regions (i.e., turbinate, nasopharynx, pharynx, and larynx) was quite different among the four subjects considered. Sponsored Research - None Image-based nasal airway model of (a) 10-day-old girl (neonate), (b) a 7-month-old girl (infant), (c) a 3-year-old girl, and (d) a five-year-old boy (child).