Neurocognitive Function and Cerebral Perfusion in Cardiac Surgery

描述（由申请人提供）：心脏手术后的神经认知功能障碍是一种公认的并发症，影响约50%的出院患者。脑是最容易受到心肺转流（CPB，即心肺机）期间灌注不足损伤的器官，但由于缺乏用于监测术中脑灌注的可行模式，脑也是手术期间监测最少的器官。该项目的主要目的是使近红外光谱（NIRS）断层扫描适应术中监测。NIRS断层扫描提供了时间和空间脑灌注的实时测量，空间分辨率与功能MRI相当，但时间分辨率明显更好。除了在传统的还原框架（氧合血红蛋白，脱氧血红蛋白，总血红蛋白分别考虑）的数据分析，一种新的对比度增强方法，基于解决每种形式的血红蛋白分为六个类别，是敏感的诱导氧债，将被应用于进一步细化脑灌注模式的空间和时间特征。该项目的最终目标是确定可逆阶段后续神经认知功能障碍的术中生物标志物。本项目将招募至少50名心脏手术患者和25名接受不涉及CPB的开胸手术的患者（对照组）。他们将在手术前后接受一系列标准的神经认知测试。将进行脑灌注的术中NIRS成像并进行分析，以确定缺氧区域以及缺氧应激的持续时间和幅度。将对神经认知测试结果以及外科医生、麻醉师和灌注师的术中操作记录进行比较，以确定哪些与缺氧事件共变，并预测随后的神经功能缺损。将研究已识别的事件，以确定受影响受试者组中是否存在共同特征，提示在手术期间采取适当对策以逆转或预防脑灌注不良。这些研究的结果将为辨别心脏手术期间循证脑保护方案提供基础。此外，基于实时NIRS成像，可以做出改进的术中管理决策，以提醒临床医生注意灌注不足的罪犯特征模式，并评估抢救措施的有效性。 公共卫生相关性：神经认知功能障碍是心脏手术后常见的并发症。本计画旨在利用近红外线光学断层摄影术在术中监测脑灌注.收集的信息将有助于外科医生和麻醉师适当地管理患者，以防止神经系统并发症。

DESCRIPTION (provided by applicant): Neurocognitive dysfunction after cardiac surgery is a well-recognized complication that affects about 50% of patients at discharge. The brain is the organ most susceptible to damage from inadequate perfusion during cardiopulmonary bypass (CPB, i.e. heart-lung machine), but it is also the organ least monitored during surgery, due to the absence of a feasible modality for monitoring intraoperative cerebral perfusion. The broad aim of this project is to adapt near-infrared spectroscopic (NIRS) tomography to intraoperative monitoring. NIRS tomography provides real-time measures of the temporal and spatial cerebral perfusion, with spatial resolution comparable to functional MRI, but with significantly better temporal resolution. In addition to analysis of data within a conventional reductionistic framework (oxyhemoglobin, deoxyhemoglobin, and total hemoglobin considered separately), a novel contrast-enhancement method, based on resolving each form of hemoglobin into six categories that are sensitive to induced oxygen debt, will be applied to further refine spatial and temporal features of cerebral perfusion patterns. The ultimate goal of this project is to identify intraoperative biomarkers of subsequent neurocognitive dysfunction at a reversible stage. A minimum of 50 cardiac surgical patients, and 25 patients undergoing open chest surgery not involving CPB (control group), will be recruited for this project. They will undergo a standard battery of neurocognitive tests before and after surgery. Intraoperative NIRS imaging of cerebral perfusion will be performed and analyzed to identify areas of hypoxia, as well as the duration and magnitude of hypoxic stress. Comparison will be made to neurocognitive test results, as well as to records of intraoperative maneuvers by surgeons, anesthesiologists, and perfusionists, to determine which of these co-vary with the hypoxic events and are predictive of subsequent neurological deficit. Identified events will be studied to determine whether common features exist within the affected subject group that is suggestive of appropriate countermeasures during surgery to reverse or forestall cerebral malperfusion. Results from these studies will provide a basis for discerning an evidence-based cerebral protection protocol during cardiac surgery. Furthermore, improved intraoperative management decisions can be made, based on real-time NIRS imaging, to alert clinicians to culprit signature patterns of hypoperfusion and to assess the effectiveness of rescue maneuvers. PUBLIC HEALTH RELEVANCE: Neurocognitive dysfunction is a common complication after cardiac surgery. This project aims to utilize near- infrared optical tomography to monitor cerebral perfusion in intraoperative settings. The information gathered will help surgeons and anesthesiologists manage patients appropriately to prevent neurological complications.