Respiratory Control Stability in Obstructive Sleep Apnea

描述(由申请人提供)：阻塞性睡眠呼吸暂停(OSA)是一种常见的疾病，其特征是睡眠期间咽部呼吸道反复塌陷。有证据表明，呼吸控制不稳定(RCI)是阻塞性睡眠呼吸暂停综合征(OSA)发病的重要因素。最近引入了一种新的量化RCI的技术，涉及到呼吸系统环增益(Lg)的测量。LG是一个工程术语，描述了由反馈控制回路控制的机械或生理系统中的不稳定性。在数学上，它被定义为矫正反应(例如，呼吸暂停)与干扰(例如，呼吸暂停)的比率。如果纠正措施的大小大于干扰(LG&gt；1)，则系统被认为是不稳定的，在受到干扰时可能会出现持续的周期性波动(例如，在通风和血气方面)。这项建议的目的是使用这项新技术来更好地确定RCI和OSA发病机制的作用。具体来说，我们建议： 1.修改目前的技术，在轻度缺氧条件下测量Lg，我们相信这将使我们能够量化呼吸控制稳定(Lg接近于零)的个体的RCI。 2.测量具有呼吸暂停严重程度的患者的Lg和上呼吸道塌陷性(咽部关闭压力，Pcrit)，以确定是否： A.具有相对上呼吸道塌陷性(Pcrit)的个体需要较高的Lg(Lg接近1)才能发展为OSA。 高Lg与上呼吸道塌陷无关，与更严重(更常见的呼吸暂停)OSA相关。 C.低Lg将减轻高Lg患者的OSA严重程度。

DESCRIPTION (provided by applicant): Obstructive sleep apnea (OSA) is a common disorder characterized by recurrent collapse of the pharyngeal airway during sleep. There is evidence to suggest that respiratory control instability (RCI) is an important contributor to OSA pathogenesis. A novel technique for quantifying RCI has recently been introduced and involves the measurement of respiratory system loop gain (LG). LG is an engineering term that describes the instability in a mechanical or physiologic system governed by feedback control loops. Mathematically, it is defined as the ratio of a corrective response (e.g., hyperpnea) to a disturbance (e.g., apnea). If the corrective action is greater in magnitude than the disturbance (LG > 1), the system is said to be unstable and has the potential for sustained, periodic fluctuations (e.g., in ventilation and blood gases) when disturbed. The purpose of this proposal is to use this new technique to better define the role of RCI and OSA pathogenesis. Specifically, we propose to: 1. Modify the current technique by measuring LG under mildly hypoxic conditions, which we believe will allow us to quantify RCI in individuals with stable (LG close to zero) respiratory control. 2. Measure LG and upper airway collapsibility (pharyngeal closing pressure, Pcrit) in patients with a spectrum of apnea severity to determine if: a. Individuals with relatively upper airway collapsibility (Pcrit) require a high LG (LG close to 1) to develop OSA. b. High LG, independent of upper airway collapsibility, is associated with more severe (more frequently apneas) OSA. c. Lower LG will reduce OSA severity in patients with high LG.