Using Two-Way Fluid-Structure Interaction to Study the Collapse of the Upper Airway of OSA Patients

2014 ◽  
Vol 553 ◽  
pp. 275-280 ◽  
Author(s):  
Mo Yin Zhao ◽  
Tracie J. Barber ◽  
Peter A. Cistulli ◽  
Kate Sutherland ◽  
Gary Rosengarten
Keyword(s):  
Computational Models ◽  
Treatment Success ◽  
Fluid Structure Interaction ◽  
Maximum Velocity ◽  
Upper Airway ◽  
Post Treatment ◽  
Mandibular Advancement ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Obstructive Sleep

Obstructive Sleep Apnea (OSA) is a common sleep disorder characterized by repetitive collapse of the upper airway (UA) during sleep. Treatment options for OSA include mandibular advancement splints (MAS), worn intra-orally to protrude the lower jaw to stabilize the airway. However not all patients will respond to MAS therapy and individual effects on the upper airway are not well understood. Simulations of airway behavior represent a non-invasive means to understand this disorder and treatment responses in individual patients. The aims of this study was to perform analysis of upper airway (UA) occlusion and flow dynamics in OSA using the fluid structure interaction (FSI) method, and secondly to observe changes associated with MAS usage. Magnetic resonance imaging (MRI) scans were obtained with and without mandibular advance splint (MAS) treatment in a patient known to be a treatment responder. Computational models of the anatomically correct UA geometry were reconstructed for both pre-and post-treatment (MAS) conditions. By comparing the simulation results, the treatment success of MAS was demonstrated by smaller UA structure deformation (maximum 2mm) post-treatment relative to the pre-treatment fully collapsed (maximum 6mm) counterpart. The UA collapse was located at the oropharynx and the low oropharyngeal pressure (-51 Pa to-39 Pa) was induced by the velopharyngeal jet flow (maximum 10 m/s). The results support previous OSA computational fluid dynamics (CFD) studies by indicating similar UA pressure drop and maximum velocity values. These findings lay a firm platform for the application of computational models for the study of the biomechanical properties of the upper airway in the pathogenesis and treatment of OSA.

scholarly journals Simulation of the Retroglossal Fluid-Structure Interaction During Obstructive Sleep Apnea

2006 ◽  
pp. 48-57 ◽  
Author(s):  
Franz Chouly ◽  
Annemie Van Hirtum ◽  
Pierre-Yves Lagrée ◽  
Jean-Roch Paoli ◽  
Xavier Pelorson ◽  
...  
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Obstructive Sleep

Novel avenues to approach non-CPAP therapy and implement comprehensive OSA care

2021 ◽  
pp. 2101788
Author(s):  
Jean-Louis Pépin ◽  
Peter Eastwood ◽  
Danny J. Eckert
Keyword(s):  
Treatment Success ◽  
Clinical Manifestations ◽  
Upper Airway ◽  
Sleep Apnoea ◽  
Mandibular Advancement ◽  
Individual Risk ◽  
Future Research ◽  
Success Rates ◽  
Recent Advances ◽  
Obstructive Sleep

Recent advances in obstructive sleep apnoea (OSA) pathophysiology and translational research have opened new lines of investigation for OSA treatment and management. Key goals of such investigations are to provide efficacious, alternative treatment and management pathways that are better tailored to individual risk profiles to move beyond the traditional, continuous positive airway pressure (CPAP)-focused, “one size fits all”, trial and error approach which is too frequently inadequate for many patients. Identification of different clinical manifestations of OSA (clinical phenotypes) and underlying pathophysiological phenotypes (endotypes), that contribute to OSA have provided novel insights into underlying mechanisms and have underpinned these efforts. Indeed, this new knowledge has provided the framework for precision medicine for OSA to improve treatment success rates with existing non-CPAP therapies such as mandibular advancement devices and upper airway surgery, and newly developed therapies such as hypoglossal nerve stimulation and emerging therapies such as pharmacotherapies and combination therapy. These concepts have also provided insight into potential physiological barriers to CPAP adherence for certain patients. This review summarises the recent advances in OSA pathogenesis, non-CPAP treatment, clinical management approaches and highlights knowledge gaps for future research. OSA endotyping and clinical phenotyping, risk stratification and personalised treatment allocation approaches are rapidly evolving and will further benefit from the support of recent advances in e-health and artificial intelligence.

scholarly journals Image-Guided Fluid-Structure Interaction Simulation of Transvalvular Hemodynamics: Quantifying the Effects of Varying Aortic Valve Leaflet Thickness

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 119 ◽  
Author(s):  
Anvar Gilmanov ◽  
Alexander Barker ◽  
Henryk Stolarski ◽  
Fotis Sotiropoulos
Keyword(s):  
Blood Flow ◽  
Aortic Valve ◽  
Heart Valve ◽  
Fluid Structure Interaction ◽  
Maximum Velocity ◽  
Patient Specific ◽  
Hemodynamic Parameters ◽  
Orifice Area ◽  
Fluid Structure ◽  
Structure Interaction

When flow-induced forces are altered at the blood vessel, maladaptive remodeling can occur. One reason such remodeling may occur has to do with the abnormal functioning of the aortic heart valve due to disease, calcification, injury, or an improperly-designed prosthetic valve, which restricts the opening of the valve leaflets and drastically alters the hemodynamics in the ascending aorta. While the specifics underlying the fundamental mechanisms leading to changes in heart valve function may differ from one cause to another, one common and important change is in leaflet stiffness and/or mass. Here, we examine the link between valve stiffness and mass and the hemodynamic environment in aorta by coupling magnetic resonance imaging (MRI) with high-resolution fluid–structure interaction (FSI) computational fluid dynamics to simulate blood flow in a patient-specific model. The thoracic aorta and a native aortic valve were re-constructed in the FSI model from the MRI data and used for the simulations. The effect of valve stiffness and mass is parametrically investigated by varying the thickness (h) of the leaflets (h = 0.6, 2, 4 mm). The FSI simulations were designed to investigate systematically progressively higher levels of valve stiffness by increasing valve thickness and quantifying hemodynamic parameters known to be linked to aortopathy and valve disease. The computed results reveal dramatic differences in all hemodynamic parameters: (1) the geometric orifice area (GOA), (2) the maximum velocity V max of the jet passing through the aortic orifice area, (3) the rate of energy dissipation E ˙ diss ( t ) , (4) the total loss of energy E diss , (5) the kinetic energy of the blood flow E kin ( t ) , and (6) the average magnitude of vorticity Ω a ( t ) , illustrating the change in hemodynamics that occur due to the presence of aortic valve stenosis.

scholarly journals Dealing with the Effect of Air in Fluid Structure Interaction by Coupled SPH-FEM Methods

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1162 ◽  
Author(s):  
Cristiano Fragassa ◽  
Marko Topalovic ◽  
Ana Pavlovic ◽  
Snezana Vulovic
Keyword(s):  
Finite Element Method ◽  
Smoothed Particle Hydrodynamics ◽  
Computational Models ◽  
Fluid Structure Interaction ◽  
The Finite Element Method ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
High Computational Complexity

Smoothed particle hydrodynamics (SPH) and the finite element method (FEM) are often combined with the scope to model the interaction between structures and the surrounding fluids (FSI). There is the case, for instance, of aircrafts crashing on water or speedboats slamming into waves. Due to the high computational complexity, the influence of air is often neglected, limiting the analysis to the interaction between structure and water. On the contrary, this work aims to specifically investigate the effect of air when merged inside the fluid–structure interaction (FSI) computational models. Measures from experiments were used as a basis to validate estimations comparing results from models that include or exclude the presence of air. Outcomes generally showed a great correlation between simulation and experiments, with marginal differences in terms of accelerations, especially during the first phase of impact and considering the presence of air in the model.

MODELING OF ILIAC ARTERY ANEURYSM USING FLUID–STRUCTURE INTERACTION

2015 ◽  
Vol 15 (01) ◽  
pp. 1550041 ◽  
Author(s):  
HATEF SABOONI ◽  
KAMRAN HASSANI ◽  
HAMIDREZA GHASEMI BAHRASEMAN
Keyword(s):  
Iliac Artery ◽  
Computational Models ◽  
Fluid Structure Interaction ◽  
Artery Aneurysm ◽  
Computational Method ◽  
Discussion Section ◽  
Iliac Artery Aneurysm ◽  
Fluid Structure ◽  
Shear Rates ◽  
Structure Interaction

The aneurysm of iliac artery is a rare entity and there are few computational models that have studied the disease. In this study, we have presented the flow patterns in the aneurysmal artery using Fluid–structure interaction method. The blood was assumed Newotonian, pulsatile, laminar, incompressible, and homogenous. The geometry of the model was made based on CT images of clinical cases. Using the computational method, we have obtained the velocity and pressure contours, shear rates and vortices for the healthy and aneurysmal artery. The results show that a pressure maximum was found at the midpoint of the dilation. The vortices are formed in the aneurysmal area26 and shear rates do not change much. However, the rate increased in the neck of aneurysms. Furthermore, the aneurysm with bigger dilation tend to rupture due to more shear rates in the neck and the velocity at peak systole decreases in the aneurysmal area due to increase of the artery diameter. We have compared our results with some available relevant clinical data in discussion section.

Computational dynamic models and experiments in the fluid–structure interaction of pipe systems

2016 ◽  
Vol 43 (1) ◽  
pp. 60-72 ◽  
Author(s):  
M. Simão ◽  
J. Mora-Rodriguez ◽  
H.M. Ramos
Keyword(s):  
Computational Models ◽  
Dynamic Models ◽  
Numerical Models ◽  
Fluid Structure Interaction ◽  
Rheological Behaviour ◽  
Pipe Material ◽  
Expansion Joints ◽  
Fluid Structure ◽  
Pipe System ◽  
Structure Interaction

Fluid–structure interaction is analyzed using 1D and 3D computational models and results from an experimental facility, where transient events are induced. The water-hammer phenomenon is modelled by a 1D model based on the method of characteristics and the COMSOL Multiphysics 4.3b, which uses finite element method to study the fluid structural interaction involved in a long pressurized pipe system with curves, expansion joints, anchor and support blocks and different rheological behaviour of the pipe material. Comparisons are made between the experimental data and the two numerical models, where the type of response of each model was enhanced, as well as the ability of each model to simulate real conditions.

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