Improved Accuracy of NIRS-based Skeletal Muscle Oxygen Saturation Measurement through Model Creation and Advanced Signal Processing Techniques

描述(申请人提供)：近红外光谱(NIRS)血氧仪有可能测量大脑、肌肉和其他器官的组织氧合，以改善对输血、休克、缺氧-缺血和血管疾病的管理。然而，目前可用的近红外组织血氧仪要么主要针对大脑氧合测量进行校准，要么针对有限深度的其他组织进行校准，这限制了这些临床条件的准确性或适用性。这项计划的目的是开发基于LED的近红外组织血氧传感器，能够测量表面几厘米深的骨骼肌氧合。传感器的设计将减少测量对象之间的变异性，提高测量的准确性。这一测量深度将允许应用于监测外周动脉疾病、休克检测和血细胞输注。主要里程碑包括： ·通过血管闭塞研究，确定影响近红外组织血氧仪准确性的骨骼肌组织的光学光特性 ·确定利用脂质混合技术改进的体外血液-组织模型是否能够充分反映血液组织的光学特征 ·确定动态路径长度调整信号处理的有效性，以减少受试者之间的变异性并提高骨骼肌组织血氧仪的准确性 体外模型允许已知和可控的参考值，但无法模拟适当的组织散射特性。断肢模型已经过测试，但也不一定代表近红外光谱测量的活体人体组织的散射特性。人体血管闭塞模型允许评估适当的光散射特性，但不能控制或已知参考饱和度。改进的体外模型和血管闭塞研究与先进的信号处理技术相结合的方法将改变体外建模，以更好地代表组织的光学特征。最终的结果将是一个健壮的骨骼肌组织模型和一个组织氧饱和度传感器，提高了骨骼肌测量的准确性，并减少了受试者之间的变异性。第二阶段的工作将集中于扩展到外周动脉疾病(PAD)患者的下肢闭塞研究和验证，以记录存在斑块时骨骼肌的光学特性特征，以及用于纠正光学变化的可能的光路调整技术。最终的商业化包括一种手持便携式设备，它将支持在多种临床环境中对肌肉氧合进行现场检查，并可能扩展到可穿戴的移动设备。

DESCRIPTION (provided by applicant): Near infrared spectroscopy (NIRS) oximeters have the potential to measure tissue oxygenation in brain, muscle, and other organs to improve management of blood transfusion, shock, hypoxia-ischemia, and vascular disease. However, currently available NIRS tissue oximeters have either been calibrated primarily for cerebral oxygenation measurements or for other tissues at a limited depth, limiting accuracy or applicability to these clinical conditions. The aim of this proposal is to develop LED-based NIRS tissue oximetry sensors capable of measuring skeletal muscle oxygenation several centimeters deep to the surface. The sensor design will decrease inter-subject variability of the measurement and improve accuracy of the measurement. This depth of measurement will allow for application to monitor peripheral artery disease, shock detection, and blood cell transfusion. Key milestones include: • Determine optical light characteristics of skeletal muscle tissue which impact accuracy of NIRS tissue oximetry through a vascular occlusion study • Determine if an improved ex vivo blood-tissue model utilizing lipid mixing techniques can adequately represent blood tissue optical characteristics • Determine effectiveness of dynamic path-length adjustment signal processing to reduce inter-subject variability and improve skeletal muscle tissue oximetry accuracy Ex vivo models allow for known and controllable reference values, but fail to model the appropriate tissue scattering properties. Severed limb models have been tested, but also do not necessarily represent the scattering properties of living human tissue measured by NIRS. Human vascular occlusion models allow for appropriate light scattering properties to be assessed, but fail to have controlled or known reference saturations. A combined approach of an improved ex vivo model and a vascular occlusion study with advanced signal processing techniques will be incorporated, altering the ex vivo modeling to better represent optical characteristics of tissue. The end result will be a robust model of skeletal muscle tissue and a tissue oximetry sensor with improved accuracy for skeletal muscle measurement and reduced inter-subject variability. Phase II work will focus on expanding into lower limb occlusion studies and validation in peripheral arterial disease (PAD) patients to document characterization of the optical properties of skeletal muscle in the presence of plaque and possible light path adjustment techniques for correcting alterations in optics. Eventual commercialization includes a hand held portable device that will support spot check of muscle oxygenation in multiple clinical settings with possible extension to a wearable, mobile device.