DYNAMIC MODELING OF STATE CARDIORESPIRATORY INTERACTIONS

心肺相互作用状态的动态建模

• 批准号: 6205812
• 负责人: MICHAEL C KHOO
• 金额: $ 14.11万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2000-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6205812
• 关键词: aging; anesthesiology; bioengineering /biomedical engineering; biomedical resource; nervous system; respiratory system; statistics /biometry; technology /technique

The overall goal of this project is to develop models of, and computational strategies for analyzing, the dynamics of interacting closed-loop physiological systems; in particular, the project focuses on elucidating the complex interactions between respiratory control and the control of sleep-wake state. In the past year, we continued to develop a minimal model for delineating the chemoreflex-mediated changes from state-induced fluctuations in respiratory drive. We found that approximately 19% of the respiratory variability in obstructive sleep apneics (OSA) during CPAP (continuous positive airway pressure) therapy could be attributed to chemoreflex-mediated fluctuations in drive. Thus, contrary to expectations, this chemoreflex contribution is not significantly smaller than the 25% found in normals. The estimated chemoreflex loop gain in both groups was not statistically different; however, the characteristic time for the chemoreflex-mediated responses in OSA was only ~60% as long as that for normals. These results suggest that ventilatory stability in OSA subjects is reduced relative to normal controls, and support the hypothesis that respiratory control instability may be a key factor in the pathogenesis of OSA. We also developed an improved methodology for assessing autonomic function in patients with OSA. This methodology is based on two new indices computed from spectral measures of respiration and heart rate variability: the modified ratio of low-frequency to high-frequency power (MLHR) and the average gain relating respiration to RR changes (GRSA). Significant changes resulted in MLHR and GRSA during acute application of CPAP in OSA patients, while no changes in more traditional measures of autonomic function were detectable. We applied spectral analysis and system identification techniques to data obtained from cocaine-exposed and control full-term neonates at two weeks of age during quiet sleep (QS) and active sleep (AS). The cocaine-exposed neonates showed enhanced heart rate variability that was due to an increase in spectral power across all frequency bands during QS, but only in the low-and mid-frequency power bands in AS. The dynamic relationship between respiration and heart rate showed no statistically significant differences between the subject groups or between states. However, a significant interaction effect (P<0.03) between group and state was found. These results suggest an increase in both sympathetic and parasympathetic modulation of heart rate in cocaine-exposed infants.

该项目的总体目标是开发模型和 分析的计算策略，交互的动态 闭环生理系统；特别是，该项目重点 阐明呼吸控制之间的复杂相互作用 以及对睡眠效果状态的控制。 在过去的一年中，我们继续 开发一个最小模型来描述化学反射介导的 呼吸驱动中国家引起的波动发生的变化。 我们 发现大约有19％的呼吸变异性 CPAP期间阻塞性睡眠呼吸暂停（OSA）（连续阳性 气道压力）治疗可以归因于化学反射介导的 驱动器的波动。 因此，与期望相反， ChemoreFlex的贡献不小于25％ 在正常中发现。 两组的估计化学反射回路增益 在统计学上没有不同；但是，特征时间 OSA中的化学反射介导的反应仅为60％ 对于正常人。 这些结果表明在 相对于正常对照组，OSA受试者减少了，并支持 假设呼吸控制不稳定性可能是一个关键因素 OSA的发病机理。 我们还开发了一种改进的方法 用于评估OSA患者的自主功能。 这 方法学是基于从光谱计算的两个新索引 呼吸和心率变异性的度量：修改后 低频与高频功率（MLHR）的比率和平均值 获得与RR变化有关的呼吸（GRSA）。 重大变化 在OSA中急性应用CPAP时，导致MLHR和GRSA 患者，虽然更传统的自主措施没有变化 功能可检测到。 我们应用光谱分析和系统 识别从可卡因暴露获得的数据和 在安静的睡眠（QS）中控制两个星期大的新生儿（QS） 和活跃的睡眠（AS）。 可卡因暴露的新生儿显示出增强的 频谱功率增加引起的心率变异性 在QS期间的所有频带中，但仅在低和 中频频段。 之间的动态关系 呼吸和心率没有统计学意义 主题群体或国家之间的差异。 However, a 组和状态之间的显着相互作用效应（p <0.03）为 成立。 这些结果表明同情和 可卡因暴露婴儿心率的副交感神经调节。