Novel Sensor for Measurement of Blood Oxygenation

描述（由申请人提供）：管理急性，危及生命的神经系统疾病，如严重的创伤性脑损伤，是通过准确和持续的脑氧合监测促进。然而，目前的监测系统是侵入性的，需要在颈内静脉球内插管或将探针直接插入大脑。虽然风险相对较低，但持续的颈静脉球监测在技术上是艰巨的。近红外光谱是一种无创监测脑血氧的方法，很有前景，但尚未提供成人的定量测量。目前还没有准确、无创、连续监测脑血氧的系统。我们提出并进行了一种新型光声传感器的体外和体内测试，该传感器可以直接从上矢状窦精确连续地测量血液氧合，由于光声技术的高分辨率，这种结构可以很容易地定位。光声技术是基于激光脉冲产生超声波（光声）波，并通过灵敏的声换能器检测这些波。光声监测血液氧合利用在近红外光谱范围内氧和脱氧血红蛋白的光学吸收系数的既定差异。在我们目前的NIH R21项目（由项目公告PA-98-050支持，旨在开发包括光声脑监测在内的创新技术）中，我们设计、建造并测试了一种便携式、无创光声系统，用于准确监测脑血氧。我们在体外和体内（绵羊）的研究表明：(1)光声波的参数与血氧呈线性关系；(2)使用特殊设计的换能器和光声探头，尽管厚骨会造成光学和声学衰减，但仍然可以进行灵敏的检测；(3)该技术可以高精度地测量血氧。在这项拨款申请中，我们建议通过临床测试来进一步开发这种传感器。该项目的具体目标是：(1)评估尸体上的传感器；(2)开发一种在线计算志愿者体内血氧饱和度的算法；(3)在第二组志愿者中验证传感器的性能。到项目结束时，传感器将发展到足以允许多中心临床评估。除了大脑监测外，该传感器还可以用于其他器官的局部无创血氧测量。

DESCRIPTION (provided by applicant): Management of acute, life-threatening neurologic illnesses, such as severe traumatic brain injury, is facilitated by accurate and continuous monitoring of cerebral oxygenation. However, current monitoring systems are invasive, requiring either cannulation of the internal jugular venous bulb or insertion of a probe directly into the brain. Although relatively low-risk, continuous jugular venous bulb monitoring is technically arduous. Near-infrared spectroscopy, a noninvasive method of monitoring cerebral blood oxygenation, is promising, but has yet to provide quantitative measurement in adults. At present there is no system for accurate, non-invasive, and continuous monitoring of cerebral blood oxygenation. We proposed and performed in vitro and in vivo testing of a novel optoacoustie sensor that accurately and continuously measures blood oxygenation directly from the superior sagittal sinus, a structure that can easily be localized due to the high resolution of the optoacoustic technique. The optoacoustic technique is based on generation of ultrasonic (optoacoustic) waves by laser pulses and detection of these waves by a sensitive acoustic transducer. Optoacoustic monitoring of blood oxygenation utilizes well-established differences in the optical absorption coefficients of oxy- and deoxyhemoglobin in the near-infrared spectral range. During our current NIH R21 project (supported under Program Announcement PA-98-050 directed at the development of innovative technologies including photoacoustic brain monitoring), we designed, built, and tested a portable, noninvasive optoacoustic system for accurate monitoring of cerebral blood oxygenation. Our in vitro and in vivo (in sheep) studies demonstrated that: (1) the parameters of the optoacoustic waves are linearly dependent on blood oxygenation; (2) the use of specially designed transducers and optoacoustic probes allows sensitive detection despite optical and acoustic attenuation by thick bone; and (3) this technique can measure blood oxygenation with high accuracy. In this grant application, we propose to further develop this sensor by testing it clinically. The specific aims of the project are: (1) to evaluate the sensor in cadavers; (2) to develop an algorithm for calculating oxygen saturation on-line in vivo in volunteers; and (3) to validate the sensor performance in a second group of volunteers. By the end of the project the sensor will be developed sufficiently to permit multi-center clinical evaluation. In addition to brain monitoring, the proposed sensor can potentially be used for local non-invasive measurement of blood oxygenation in other organs.