Blood flow oscillations and early detection of pressure ulcers in older adults

描述（由申请人提供）：血流振荡（BFO）是评估微血管功能障碍和压力性溃疡风险的新兴生物标志物。研究表明，BFO受内皮代谢、交感迷走神经源性和血管肌源性控制机制的调控。通过评估BFO的变化，可以进一步量化组织活力和缺血损伤。这些知识对于早期发现压疮以及评估预防性干预措施的有效性是必需的。然而，并没有根据BFO值来定义组织活力的好坏。我们建议量化BFO与衰老和缺乏运动相关的变化，以研究微血管功能障碍在压疮发生中的作用。这些信息可用于老年人群压疮的早期检测。本研究的长期目标是在分析BFO的线性和非线性特性的基础上，建立早期发现压疮的方法，并利用这些方法评估预防性干预对提高老年人组织活力的效果。本研究的目的是量化具有不同程度压疮风险的老年人BFO在衰老、不活动和缺血（1期压疮前的软组织状态）时线性和非线性动力学特性的变化。具体目的1是通过分析BFO的线性和非线性特性，研究衰老和缺乏运动对组织活力的影响。线性分析包括小波变换、希尔伯特变换和经验模态分解。非线性分析包括Hurst指数、去趋势波动分析、相关维数、样本熵和Lyapunov指数。本研究将建立对BFO的线性和非线性特性及其与压疮风险关系的基本认识。具体目的2是研究BFO的线性和非线性特性的变化是否可以用于预测压疮。目前，我们假设BFO的线性和非线性特性的下降与压疮的风险有关。我们将在连续24周的时间内测量BFO，以捕捉正常、下降、1期压疮前期和压疮发病阶段BFO的变化。如果成功，我们将能够使用这些信息来评估软组织是否处于良好的生存能力，缺血或1期压疮前期阶段。

DESCRIPTION (provided by applicant): Blood flow oscillations (BFO) is an emergent biomarker to assess micro vascular dysfunction and risk for pressure ulcers. Research studies have demonstrated that BFO is regulated by endothelial metabolic, sympathovagal neurogenic, and vascular myogenic control mechanisms. By assessing the changes of BFO, tissue viability and ischemic injury can be further quantified. Such knowledge is needed to early detect pressure ulcers as well as to assess efficacy of preventive interventions. However, there is no definition of good or poor tissue viability based on the values of BFO. We propose to quantify the changes of BFO associated with aging and physical inactivity to investigate the role of micro vascular dysfunction in developing pressure ulcers. Such information can be used to early detect pressure ulcers in the elderly population. The long-term goal of this study is to develop methods for early detection of pressure ulcers based on the analysis of linear and nonlinear properties of BFO and then to use the methods to assess the efficacy of preventive interventions on enhancing tissue viability in older adults. The objectives of this study are to quantify the changes of linear and nonlinear dynamical properties of BFO in response to aging, inactivity, and ischemia (soft tissue status before stage 1 pressure ulcers) in older people with various levels of risk for pressure ulcers. Specific aim 1 is to investigate the effects of aging and physical inactivity on tissue viability through analysis of linear and nonlinear properties of BFO. Linear analyses include wavelet and Hilbert transforms and empirical mode decomposition. Nonlinear analyses include Hurst exponent, detrended fluctuation analysis, correlation dimension, sample entropy, and Lyapunov exponent. This study will establish the basic understanding of linear and nonlinear properties of BFO and their relationships with risk for pressure ulcers. Specific aim 2 is to examine whether the changes of linear and nonlinear properties of BFO can be used to predict pressure ulcers. Currently we hypothesize that a decline of linear and nonlinear properties of BFO is associated with the risk for pressure ulcers. We will measure BFO in a consecutive 24-week period to capture the changes of BFO from normal, declined, pre stage 1 pressure ulcers, and onset of pressure ulcers stages. If successful, we will be able to use the information to assess whether soft tissue is under good viability, ischemia, or pre-stage 1 pressure ulcer phases. PUBLIC HEALTH RELEVANCE: This study will establish the foundation to develop assessment tools based on linear and nonlinear properties of blood flow oscillations that will guide clinicians for the early detection of pressure ulcers in older people with physical disabilities.