Flow distribution in human and canine tracheobronchial airway casts.
Health Phys 1989 Jul; 57(1):21-27
This report provided quantitative data on airflow distribution in a realistic central airway cast for two species and for two different airflow patterns: steady inspiratory flow and pulsatile inspiratory flow. Two hollow airway casts were produced, one human and one canine. Measurements of flow rates through these cases were made and showed basic similarities in the distribution of airflow. These measurements also indicated species differences which must be considered in such studies. For both constant and pulsatile inspiratory flow, the distribution of air flow was measured for minute volumes equivalent to 6, 11, 17 and 22 liters/minute for the human and 3, 6, 8, and 11 liters/minute for the dog. Inertia of air flow carried more of the flow to airways of the lower lobes at higher flow rates. The basic differences in airway branching pattern result in a more distinct change in airflow distribution as flow rate changes for the canine cast as compared with the human cast. In-vivo, the inertial effect on distribution of airflow was probably damped by lung tissue compliance, and the tendency of airflow to redistribute from the upper to the lower lobes at higher flow rates may be less pronounced. Results suggested that these differences contribute to differing patterns of mass transfer of inhaled particles and gases in central airways of the two species. The authors indicate that studies of deposition in such hollow casts as these, particularly at lower flow rates, should provide realistic comparisons of mass transfer to airway surfaces.
NIOSH-Publication; NIOSH-Grant; Pulmonary-system-disorders; Pulmonary-function; Airway-resistance; Laboratory-animals; Air-flow
Environmental Medicine New York Univ Medical Center 550 First Avenue New York, N Y 10016
New York University, New York, New York