Extrathoracic deposition

For extrathoracic deposition of particles, the model uses measured airway diameters and experimental data, where deposition is related to particle size and airflow parameters, and scales deposition for women and children from adult male data. Similar to the extrathoracic region, experimental data served as the basis for lung (bronchi, bronchioles, and alveoli) aerosol transport and deposition. A theoretical model of gas transport and particle deposition was used to interpret data and to predict deposition for compartments and subpopulations other than adult males. Table 3-4 provides reference respiratory values for the general Caucasian population during various intensities of physical exertion. 

The extrathoracic deposition fraction estimates developed in this study do not compare well with the results from Stahlhofen et al. (1983), who observed no regional deposition of particulates in the extrathoracic region. Particles of these sizes, 1 and 2 pm aerodynamic diameters, are expected to be deposited in the extrathoracic regions therefore, the discrepancy is of limited concern. This trend is consistent for individuals, regardless of the breathing pattern and gender therefore, extrathoracic deposition estimates are contrasted with theoretical data (Harvey, 2003). 

Extrathoracic deposition in adult nose breathers was shghtly less than that determined by Yu and Diu (1982). Figure 27.1 graphically depicts the theoretical results... 

Figure 27.1 Extrathoracic deposition for aduit male nose breathers.

Consequently, total deposition, DF, is the sum of extrathoracic deposition, DF, upper bronchial deposition, DF g, lower bronchial deposition, DF g, and alveolar deposition, DF ... 

VIII. Extrathoracic Deposition, Locai Side Effects, and Systemic Effects... 

Figure 10 Inspiratory extrathoracic deposition data in humans during mouth breathing as a function of the impaction parameter Q The eurve represents a hyperbolic approximation, d, aerodynamic particle diameter Q, inspiratory flow rate. (From Ref 184.)...

Extrathoracic deposition during mouth breathing (DEet-m) is derived from the collection efficiency weighted by the fraction of tidal volume (1 flowing through this region... 

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