Simulation of Respiratory System for Identifying Airway Occlusion

Abstract

A theoretical model is developed to study the dynamic response of the respiratory system using Weibel symmetric model based on the acoustic wave approach. Both rigid and compliant walls with rigid and compliant termination are investigated separately. For each case the response (normalised input impedance against prorogation frequency) is examined for occlusion at each generation from alveolar sacs up to the distal end of the trachea systematically.

Identification of airway characteristics using the input impedance

“…For any branch, the relationship between the impedance of the proximal end Z 0 and terminal end Z L may be written as [3]:…”

“…The impedance of each lobe is deduced from previous work as 32680 Pa.s/m 3 [3]. Using this impedance as the terminal impedance (for Eq.…”

“…Al-Jumaily and Mithraratne [3] developed a theoretical acoustic model of the respiratory system based on the Weibel's symmetric physiological scheme [4]. Incorporating the effect of the wall inertia, they extended Fredberg's model [1] to study the dynamic response of the respiratory system by monitoring the input impedance at the trachea.…”

“…Incorporating the effect of the wall inertia, they extended Fredberg's model [1] to study the dynamic response of the respiratory system by monitoring the input impedance at the trachea. Also Al-Jumaily and Al-Fakhiri [5,6] developed a mathematical model to study the influence of elastance variation on the respiratory system dynamics. To study the effect of the wall properties on the lung response, they incorporated the acoustical approach to determine the impedance at the throat using impedance recursion formulas for both symmetric and asymmetric structures.…”

“…To study the effect of the wall properties on the lung response, they incorporated the acoustical approach to determine the impedance at the throat using impedance recursion formulas for both symmetric and asymmetric structures. They cited that "the overall normalised input impedance frequency spectrum could be used to give a reasonable signature for identifying such abnormality" [6]. Further, Al-Jumaily and Du [7] modelled and simulated the airways for identifying and detecting obstructions.…”