Hoffman Ruddy Bari, Nadun Kuruppumullage Don, Carnaby Giselle, Crary Michael, Lehman Jeffery, Ilegbusi Olusegun J
Department of Communication Sciences and Disorders.
Department of Mechanical and Aerospace Engineering University of Central Florida Orlando Florida.
Laryngoscope Investig Otolaryngol. 2017 Jan 31;2(1):23-29. doi: 10.1002/lio2.44. eCollection 2017 Feb.
OBJECTIVE/HYPOTHESIS: Patients with laryngeal disorders often exhibit changes to cough function contributing to aspiration episodes. Two primary cough variables (peak cough flow: PCF and compression phase duration: CPD) were examined within a biomechanical model to determine their impact on characteristics that impact airway compromise.
Computational study.
A Computational Fluid Dynamics (CFD) technique was used to simulate fluid flow within an upper airway model reconstructed from patient CT images. The model utilized a finite-volume numerical scheme to simulate cough-induced airflow, allowing for turbulent particle interaction, collision, and break-up. Liquid penetrants at 8 anatomical release locations were tracked during the simulated cough. Cough flow velocity was computed for a base case and four simulated cases. Airway clearance was evaluated through assessment of the fate of particles in the airway following simulated cough.
Peak-expiratory phase resulted in very high airway velocities for all simulated cases modelled. The highest velocity predicted was 49.96 m/s, 88 m/s, and 117 m/s for Cases 1 and 3, Base case, and Cases 2 and 4 respectively. In the base case, 25% of the penetrants cleared the laryngeal airway. The highest percentage (50%) of penetrants clearing the laryngeal airway are observed in Case 2 (with -40% CPD, +40% PCF), while only 12.5% cleared in Case 3 (with +40% CPD, -40% PCF). The proportion that cleared in Cases 1 and 4 was 37.5%.
Airway modelling may be beneficial to the study of aspiration in patients with impaired cough function including those with upper airway and neurological diseases. It can be used to enhance understanding of cough flow dynamics within the airway and to inform strategies for treatment with "cough-assist devices" or devices to improve cough strength.
N/A.
目的/假设：喉部疾病患者常表现出咳嗽功能改变，这会导致误吸发作。在一个生物力学模型中研究了两个主要的咳嗽变量（峰值咳嗽流量：PCF和压缩相持续时间：CPD），以确定它们对影响气道阻塞特征的影响。
计算研究。
采用计算流体动力学（CFD）技术，对根据患者CT图像重建的上呼吸道模型内的流体流动进行模拟。该模型利用有限体积数值格式来模拟咳嗽引起的气流，考虑湍流颗粒相互作用、碰撞和破碎。在模拟咳嗽过程中，追踪8个解剖释放位置的液体渗透剂。计算了一个基础案例和四个模拟案例的咳嗽流速。通过评估模拟咳嗽后气道中颗粒的归宿来评估气道清除情况。
在所有模拟案例中，呼气高峰期气道速度都非常高。案例1和案例3、基础案例、案例2和案例4预测的最高速度分别为49.96米/秒、88米/秒和117米/秒。在基础案例中，25%的渗透剂清除了喉气道。在案例2（CPD为-40%，PCF为+40%）中，观察到清除喉气道的渗透剂比例最高（50%），而在案例3（CPD为+40%，PCF为-40%）中只有12.5%的渗透剂清除。案例1和案例4中清除的比例为37.5%。
气道建模可能有助于研究咳嗽功能受损患者的误吸情况，包括上呼吸道疾病和神经系统疾病患者。它可用于增强对气道内咳嗽流动动力学的理解，并为使用“咳嗽辅助装置”或改善咳嗽强度的装置的治疗策略提供信息。
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