A Computational Fluid Dynamics Analysis of BiPAP Pressure Settings on Airway Biomechanics Using a CT-Based Respiratory Tract Model

Respiratory Physiology & Neurobiology, Год журнала: 2025, Номер unknown, С. 104397 - 104397

Опубликована: Янв. 1, 2025

Язык: Английский

---

Effect of Infrarenal Flow Waveform on Hemodynamics of Abdominal Aortic Aneurysms and Selection of Rheology Models

Isı Bilimi ve Tekniği Dergisi, Год журнала: 2025, Номер 45(1), С. 22 - 35

Опубликована: Апрель 7, 2025

The infrarenal flow waveform (IFW) demonstrates distinct patterns in response to varying cardiac conditions, raising questions regarding the applicability of Newtonian model due variations shear rate (|γ ̇ |) distribution across different IFW patterns. This study aims investigate hemodynamic conditions generated by within an Abdominal Aortic Aneurysm (AAA) model, and their impact on predictions various rheological models. Numerical simulations are conducted using a simplified, axisymmetric AAA geometry. Three patterns, with peak systolic, diastolic, mean rates applied Newtonian, several shear-thinning viscoelastic (Oldroyd-B) compared monitoring important wall stress (WSS) descriptors including time-averaged (TAWSS), oscillatory index (OSI), endothelial cell activation potential (ECAP); |γ | distributions evolution vortex results demonstrate that even small changes influence transport mechanism (VTM) considerably. transportation time vortices from proximal distal regions bulge decreases up 50% increase rate. These alterations VTM affect distribution, causing significant Even at high rates, predicts OSI_(max ) twice as large predicted Carreau Power models, along ECAP_(max is 5 times greater. However, differences obtained Oldroyd-B relatively minor when viscous Therefore, not appropriate for simulations, cases characterized rates. Employing integrating patient-specific constants, might exhibit providing more accurate predictions. Moreover, together |, comprehensive assessment pattern resulting prior selection critical recommended.

Язык: Английский

---

Modeling Techniques and Boundary Conditions in Abdominal Aortic Aneurysm Analysis: Latest Developments in Simulation and Integration of Machine Learning and Data-Driven Approaches

Bioengineering, Год журнала: 2025, Номер 12(5), С. 437 - 437

Опубликована: Апрель 22, 2025

Research on abdominal aortic aneurysms (AAAs) primarily focuses developing a clear understanding of the initiation, progression, and treatment AAA through improved model accuracy. High-fidelity hemodynamic biomechanical predictions are essential for clinicians to optimize preoperative planning minimize therapeutic risks. Computational fluid dynamics (CFDs), finite element analysis (FEA), fluid-structure interaction (FSI) widely used simulate hemodynamics biomechanics. However, accuracy these simulations depends utilization realistic sophisticated boundary conditions (BCs), which properly integrating with rest cardiovascular system. Recent advances in machine learning (ML) techniques have introduced faster, data-driven surrogates modeling. These approaches can accelerate segmentation, predict biomechanics, assess disease progression. their reliability high-quality training data derived from CFDs FEA simulations, where BC modeling plays crucial role. Accurate BCs enhance ML predictions, increasing clinical applicability. This paper reviews existing models, discussing limitations technical challenges. Additionally, recent advancements explored, current states, future directions, common algorithms, limitations.

Язык: Английский

---

Airway stability in sleep apnea: Assessing continuous positive airway pressure efficiency

Respiratory Physiology & Neurobiology, Год журнала: 2024, Номер 325, С. 104265 - 104265

Опубликована: Апрель 21, 2024

Obstructive Sleep Apnea Syndrome (OSAS) disrupts millions of lives with its burden airway obstruction during sleep. Continuous Positive Airway Pressure (CPAP) therapy has been scrutinized for biomechanical impact on the respiratory tract. This study leverages computational fluid dynamics to investigate CPAP's effects at 9 cm H2O (882.6 Pa) computed-tomography-based nasal-to-14-generation full tract model compared ambient conditions, focusing static pressure, airflow velocity, and shear stress. Our findings reveal that CPAP significantly increases enhancing patency without adverse changes in velocity or harmful stress lung tissue, challenging prior concerns about safety. Notably, larynx experiences highest due narrow anatomy, yet overall supports walls against collapse. investigation highlights critical role OSAS treatment, offering reassurance safety efficacy. By clarifying therapy's physiological impacts, our contributes vital insights optimizing management strategies, affirming benefit maintaining open airways minimal tissue strain.

Язык: Английский

---

Large eddy simulation-based modeling of cold-air inhalation from nasal cavities to the distal lung: Insights for athlete health and performance

Results in Engineering, Год журнала: 2024, Номер 23, С. 102475 - 102475

Опубликована: Июнь 26, 2024

In cold environments, athletes are frequently susceptible to injuries from inhaling and dry air, posing significant health risks. Despite abundant prior research focusing on risk analysis prevention, the existing body of literature has predominantly focused heat transfer within lung airways while mainly overlooking broader respiratory tract. This pioneering study introduces a comprehensive assessment entire system, spanning nasal oral cavities larynx, then trachea, extending 13th generation airways. Employing cutting-edge Computational Fluid Dynamics (CFD) techniques, investigation operates Large Eddy Simulation (LES) integrated with an algebraic wall-modeled LES subgrid-scale model simulate human lung. approach provides detailed insight into complex dynamics thermoregulation in environments. By offering temperature, flux, Nusselt number static pressure profiles throughout this fundamentally advances our understanding physiological responses system air exposure. These findings have paramount implications for athlete performance, shedding light complexities cold-induced challenges. Moreover, lays solid foundation developing more effective preventive measures strategies optimizing athletic performance weather conditions.

Язык: Английский

---

A Comprehensive Numerical Study on the Transport and Deposition of Nasal Sprayed Pharmaceutical Aerosols in a Nasal‐To‐Lung Respiratory Tract Model

Particle & Particle Systems Characterization, Год журнала: 2024, Номер unknown

Опубликована: Авг. 23, 2024

Abstract Utilizing a computed tomography (CT)‐based realistic nasal‐to‐lung respiratory tract model allows for comprehensive investigation of the transport and deposition nasal sprayed aerosols. This study has three main objectives: first, to determine optimal mesh that achieves quickest convergence computational fluid‐particle dynamics (CFPD) simulations by assessing performance different element types, sizes, prism boundary layers; second, design validate numerical method compare grid data with structures densities simulation result validation; finally, observe analyze in aid development medications. involves reverse‐engineering anatomically accurate from CT scans. Results reveal approach minimum calculation time is polyhedral hybrid four layers SIMPLE pressure‐velocity coupling scheme. Furthermore, observations particle vocal cords' location contains concentration site deposited small aerosols due turbulent airflow region. The diameters target each region are concluded end.

Язык: Английский

---

Effect of red blood cell concentration on the blood flow in patient-specific aneurysms

Research on Biomedical Engineering, Год журнала: 2024, Номер 41(1)

Опубликована: Ноя. 4, 2024

Язык: Английский

---