Neuroscience Research Australia and Prince of Wales Clinical School, University of New South Wales, New South Wales, Sydney, Australia.
J Appl Physiol (1985). 2014 Feb 1;116(3):314-24. doi: 10.1152/japplphysiol.00539.2013. Epub 2013 Jul 3.
The upper airway is a complex, multifunctional, dynamic neuromechanical system. Its patency during breathing requires moment-to-moment coordination of neural and mechanical behavior and varies with posture. Failure to continuously recruit and coordinate dilator muscles to counterbalance the forces that act to close the airway results in hypopneas or apneas. Repeated failures lead to obstructive sleep apnea (OSA). Obesity and anatomical variations, such as retrognathia, increase the likelihood of upper airway collapse by altering the passive mechanical behavior of the upper airway. This behavior depends on the mechanical properties of each upper airway tissue in isolation, their geometrical arrangements, and their physiological interactions. Recent measurements of respiratory-related deformation of the airway wall have shown that there are different patterns of airway soft tissue movement during the respiratory cycle. In OSA patients, airway dilation appears less coordinated compared with that in healthy subjects (matched for body mass index). Intrinsic mechanical properties of airway tissues are altered in OSA patients, but the factors underlying these changes have yet to be elucidated. How neural drive to the airway dilators relates to the biomechanical behavior of the upper airway (movement and stiffness) is still poorly understood. Recent studies have highlighted that the biomechanical behavior of the upper airway cannot be simply predicted from electromyographic activity (electromyogram) of its muscles.
上呼吸道是一个复杂的、多功能的、动态的神经肌肉系统。其在呼吸过程中的通畅性需要神经和机械行为的时刻协调，并且会随姿势而变化。如果不能持续募集和协调扩张肌来抵消导致气道关闭的力，就会导致低通气或呼吸暂停。反复出现这种情况会导致阻塞性睡眠呼吸暂停（OSA）。肥胖和解剖结构的变化，如下颌后缩，会通过改变上呼吸道的被动机械行为增加上呼吸道塌陷的可能性。这种行为取决于每个上呼吸道组织的机械特性、它们的几何排列以及它们的生理相互作用。最近对上气道壁呼吸相关变形的测量表明，在呼吸周期中，气道软组织的运动存在不同的模式。与健康受试者（按体重指数匹配）相比，OSA 患者的气道扩张似乎不太协调。OSA 患者气道组织的固有机械特性发生了改变，但这些变化的根本原因尚未阐明。气道扩张肌的神经驱动与上气道的生物力学行为（运动和僵硬）之间的关系仍知之甚少。最近的研究强调，上气道的生物力学行为不能仅仅根据其肌肉的肌电图活动来简单预测。
