睡眠状态下上气道塌陷与阻塞的力学机制研究

发布时间：2018-03-29 12:33

本文选题：睡眠呼吸暂停　切入点：上气道　出处：《首都医科大学》2017年博士论文

【摘要】：阻塞性睡眠呼吸暂停(OSA)是一种常见的呼吸系统疾病,严重影响患者的健康与生活质量。该疾病的发生受多种因素的影响,其中之一是由于脂肪沉积或流体重新分布导致的头颈部组织体积增加。由于皮肤对组织体积向外扩张具有约束作用,所以当组织体积增加时,颈部皮肤的弹性性质在调控气道截面的形态改变方面将扮演极为关键的角色。因此,研究头颈部组织体积膨胀对上气道形态与功能的影响,以及颈部皮肤弹性性能在调控气道形态和气道阻力方面扮演的角色,对于探索气道塌陷与阻塞形成的机制,预测患病的风险,以及寻求有效的解决或控制之道极为重要。本论文包括三个部分的研究工作。第一部分针对体位由坐姿或站姿改变为睡眠时的卧姿时引起的流体向头颈部迁移现象,提出并建立一种利用磁共振成像(MRI)研究流体在重力作用下向头颈部自然迁移现象对上气道形态的影响的新方法,并对50名正常体重受试者的上气道截面和颈围变化进行测量和定量分析。研究发现流体向头颈部迁移导致的颈围增加与气道横截面面积的减少之间并不存在线性相关,因此颈围增加的程度不能作为代表气道截面尺度减少程度的指标。研究结果建议在临床上,头颈部流体重新分布后颈围几乎不变的人,而非颈围明显增加的人更易受流体迁移的影响,更具有气道变窄和阻塞的风险。本论文第二部分研究,提出并建立了一种将医学影像与有限元分析模型相结合,反推颈部皮肤在体弹性模量的方法。通过对22名健康受试者建立颈部生物力学与有限元分析模型,模拟并匹配从MRI测得的流体迁移引起的颈截面软组织和气道截面的面积变化,推算出颈部皮肤的在体弹性模量。研究表明个体间颈部皮肤的力学性质存在较大差异,其在调控气道形态方面扮演的关键角色。研究结果明确解释了在流体迁移MRI实验中观察到的现象。在第三部分研究中,我们基于一名患者的MRI图像建立头颈部三维结构,并在此基础上建立有限元分析模型,模拟和预测流体迁移现象以及其对上气道形态和阻力产生的影响。结果表明皮肤弹性模量的不同会导致不同的气道截面尺度和气道阻力变化,较多的流体进入颈部会加重气道的阻塞倾向,这可能是心衰、肾衰等伴有水肿症状的患者多患有OSA的重要原因之一。通过本论文的研究,我们建立了用MRI研究流体迁移影响的方法;建立了利用医学影像和有限元模型测量颈部皮肤在体弹性模量的方法;以及建立了用高仿真三维有限元模型模拟和预测流体迁移对气道形态和阻力影响的方法。本研究建立的方法与获得的重要结果和结论可以为探索OSA发病机制,发展新的、有效的预防和治疗方法提供重要的帮助。
[Abstract]:Obstructive sleep apnea (OSA) is a common respiratory disease that seriously affects the health and quality of life of patients. One of them is an increase in the volume of head and neck tissue due to fat deposition or fluid redistribution. The elastic properties of the neck skin will play a key role in regulating the morphological changes of the airway sections. Therefore, the effect of volume expansion of the head and neck on the morphology and function of the upper airway is studied. And the role of cervical skin elasticity in regulating airway morphology and airway resistance, to explore the mechanism of airway collapse and obstruction, and to predict the risk of disease. It is very important to find an effective solution or control. This paper includes three parts of the research work. The first part focuses on the fluid migration to the head and neck caused by the change of posture from sitting position or standing position to sleeping position. A new method for studying the effect of natural migration of fluid to head and neck on the shape of upper airway by magnetic resonance imaging (MRI) was proposed. The changes of upper airway cross-section and neck circumference in 50 normal weight subjects were measured and quantitatively analyzed. It was found that there was no linear correlation between the increase of neck circumference caused by fluid migration to the head and neck and the decrease of airway cross-sectional area. Therefore, the degree of increase in the neck circumference cannot be used as an indicator of the degree of reduction in the airway cross-sectional size. The results suggest that, in clinical practice, the neck circumference is almost unchanged after the fluid in the head and neck is redistributed. People who do not have a significantly increased neck circumference are more susceptible to fluid migration and are more at risk of narrowing and obstruction of the airway. In the second part of this paper, a new model combining medical images with finite element analysis is proposed and established. The neck biomechanics and finite element analysis (FEM) models were established in 22 healthy subjects to simulate and match the area changes of the soft tissue and airway sections of the neck section caused by fluid migration from MRI. The in vivo modulus of elasticity of neck skin was calculated. The results show that there are great differences in mechanical properties of neck skin among individuals. It plays a key role in regulating airway morphology. The results clearly explain the phenomena observed in the fluid migration MRI experiment. In the third part of the study, we established a three-dimensional structure of the head and neck based on a patient's MRI image. On this basis, the finite element analysis model is established. The effects of fluid migration on the shape and resistance of upper airway were simulated and predicted. More fluid flow into the neck may aggravate airway obstruction, which may be one of the important causes of OSA in patients with edema symptoms such as heart failure, renal failure, and so on. We established a method to study the effect of fluid migration with MRI, and a method to measure the elastic modulus of neck skin in vivo using medical imaging and finite element model. A high simulation three-dimensional finite element model was established to simulate and predict the effects of fluid migration on airway morphology and resistance. The established method and the important results and conclusions obtained in this study can be used to explore the pathogenesis of OSA and develop a new one. Effective prevention and treatment provide important help.
【学位授予单位】：首都医科大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R766

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