Measurement of particle dose distribution in a model of a human larynx and tracheobronchial tree

Abstract

Monodisperse ammonium fluorescein aerosols were deposited in combined replica human larynx casts and single-pathway tracheobronchial (TB) models. These new TB models permit control of airflow rates in airways, are constructed following anatomical measurements, and are expendable for quantification of aerosol deposition. Larynx configurations corresponded to steady inspiratory flow rates of 15, 30 and 601/min. Particle sizes ranged from 1.9 to 6.7 μm. Total larynx and TB deposition measurements are expressed in terms of a single parameter, the particle Stokes number. Intratracheobronchial dose distributions indicated large tracheal losses attributed to the laryngeal jet. Some airway bifurcations were sites of enhanced deposition. Such "hot spots" indicate high dosage to human airway cells and have important inhalation toxicology and aerosol therapy implications. Findings are in agreement with aerosol deposition data from replica TB casts and human inhalation exposure tests, which suggest that the single-pathway TB model is suitable for use in studies of factors effecting aerosol behavior and deposition in the human. © 1983.