Effects of Physical Properties of the Lung Parenchyma and Airways on Cough Efficiency

The effects of the physical parameters of the parenchyma and airways on the temporal relationships between the volume flow rate and the linear velocity of airflow in the trachea during coughing were studied using a mathematical model. It was shown that the relationship between the volume flow rate and the duration of the act of conghing can be used for assessment of inertial and viscous properties of the posterior wall of the trachea and for assessment of the parameter characterizing the nonlinearity of the intrapulmonary airway resistance. Computations indicated that the linear air velocity in the trachea and, therefore, the cough efficiency depend weakly on the physical properties of the posterior wall of the trachea and lung parenchyma.