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气道反复塌陷。有证据表明，呼吸控制不稳定（RCI）是OSA发病的重要因素。最近引入了一种量化RCI的新技术，该技术涉及呼吸系统环路增益（LG）的测量。LG是一个工程术语，描述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，它被定义为纠正反应（例如，呼吸急促）与干扰（例如，呼吸暂停）的比率。如果纠正作用的幅度大于干扰（LG bbbb1），则系统被认为是不稳定的，并且在受到干扰时具有持续周期性波动（例如通风和血气）的潜力。本建议的目的是利用这种新技术更好地定义RCI和OSA发病机制的作用。具体而言，我们建议：

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.