AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Idealized Infant and Child Throats for Mimicking Average Extrathoracic Deposition
Warren Finlay, Laleh Golshahi, Emad Javaheri, CONOR RUZYCKI, University of Alberta
Abstract Number: 227 Working Group: Health Related Aerosols
Abstract Deposition in the extrathoracic region is an important factor in determining the dose of inhaled aerosol that reaches the lungs. While realistic throat replicas are sometimes used in bench-top testing of inhalation aerosols, such replicas are too complex to be accurately and inexpensively manufactured from durable conducting materials. In addition, they only mimic deposition in one particular individual. To address these limitations, we have developed idealized child and infant extrathoracic airways. The idealized child geometry was developed by scaling the adult Alberta Idealized Throat homogeneously such that the ratio of volume to surface area is equal to the average value of this parameter in computed tomography (CT) scans of 9 orally inhaling children aged 6-14 years. Deposition in this scaled, idealized child throat for flow rates of 30-150 l/min and particle sizes of 0.5 -5.3 micrometers is found to match average values seen in realistic replicas of these 9 children (Golshahi et al., J. Aerosol Sci. 49:21-31, 2012). A comparison is also made with published in vivo deposition scintigraphic data with Turbuhaler and Qvar inhalers. Good agreement with this in vivo data is seen. An idealized infant geometry is also defined by examining CT scans of 10 infants (age 3-18 mo.) in which we have previously characterized nasal airway deposition (Storey-Bishoff et al. J. Aerosol Sci. 39:1055-1065, 2008). Deposition in this idealized infant geometry is measured with representative tidal breathing patterns and particle sizes 0.8-5.3 micrometers and found to match average values seen in the 10 realistic replicas. The present pediatric idealized throats may be useful for bench-top estimation of average extrathoracic deposition in infants and children.