FSI Analysis of a Healthy and a Stenotic Human Trachea Under Impedance-Based Boundary Conditions

Abstract

In this work, a fluid-solid interaction (FSI) analysis of a healthy and a stenotic human trachea was studied to evaluate flow patterns, wall stresses, and deformations under physiological and pathological conditions. The two analyzed tracheal geometries, which include the first bifurcation after the carina, were obtained from computed tomography images of healthy and diseased patients, respectively. A finite element-based commercial software code was used to perform the simulations. The tracheal wall was modeled as a fiber reinforced hyperelastic solid material in which the anisotropy due to the orientation of the fibers was introduced. Impedance-based pressure waveforms were computed using a method developed for the cardiovascular system, where the resistance of the respiratory system was calculated taking into account the entire bronchial tree, modeled as binary fractal network. Intratracheal flow patterns and tracheal wall deformation were analyzed under different scenarios. The simulations show the possibility of predicting, with FSI computations, flow and wall behavior for healthy and pathological tracheas. The computational modeling procedure presented herein can be a useful tool capable of evaluating quantities that cannot be assessed in vivo, such as wall stresses, pressure drop, and flow patterns, and to derive parameters that could help clinical decisions and improve surgical outcomes.

Simulation of swallowing dysfunction and mechanical ventilation after a Montgomery T-tube insertion

“…As documented in previous studies (Wall and Rabczuk 2008;Malvè, Pérez del Palomar, Trabelsi et al 2011;Malvè et al 2011a), the normal breathing pressure should be negative (with respect to the external pressure) in order to allow the collapse of the tracheal smooth muscle and correctly guarantee the physiological expiration. On the contrary, a positive pressure during expiration causes a constant overload of the trachea especially on the muscle (Figure 9).…”

“…Only few studies have been recently oriented to the coupling between fluid and solid. These studies take into account the deformation that velocity and pressure field generate in the tracheal wall (Wall and Rabczuk 2008;Malvè et al 2010;Malvè, Pérez del Palomar, Mena et al 2011;Malvè, Pérez del Palomar, Trabelsi et al 2011;Malvè et al 2011aMalvè et al , 2011b to understand the muscle collapse during normal breathing and coughing. In previous studies, we already started working on stented trachea analyzing the consequences of the introduction of a Dumon stent (Malvè, Pérez del Palomar, Trabelsi et al 2001;Wall and Rabczuk 2008;Malvè et al 2010) and comparing this results with metallic stents (Malvè, Pérez del Palomar, Mena et al 2011).…”

Computational fluid-dynamics optimization of a human tracheal endoprosthesis

“…2 -right). The identification of the different tracheal tissues was already explained in previous studies [18][19][20]. A grid independence study was carried out for the solid mesh as described in previous studies [18,19].…”

“…However, these do not take the airway deformation into account and are focused on providing detailed information of the flow features in each pulmonar branch. More recently, fluid solid interaction studies performed for tracheal geometries tube and single or multiple bifurcations can be found in literature [16][17][18][19][20][21][22].…”

Construction of healthy arteries using computed tomography and virtual histology intravascular ultrasound

“…Recent developments in computerized techniques have enabled hemodynamic approaches using numerical analysis such as computational fluid dynamics (CFD) and fluid-structure interaction (FSI), and further studies utilizing these techniques are in progress (Tse et al, 2011;Qian et al, 2010;Knight et al, 2010a;Younis et al, 2004;Valencia et al, 2009;Malv e et al, 2011;Taylor and Humphrey, 2009).…”