NIRS FOR BRAIN MONITORING IN CARDIAC SURGERY

接受先天性心脏畸形手术修复的儿童 有严重的脑损伤风险。与成年人不同的是，他们的事业 心脏手术中脑损伤的最常见的是固定或栓子 动脉粥样硬化，在儿童中最常见的原因是全球性的 缺氧/缺血。在拟议的研究中要检验的第一个假设 全球脑缺氧/缺血是可定义的、相加的结果吗 灌流参数的极端操作的相互作用 在儿童心脏手术中使用，即极端程度的低 灌注流量、低温、血液稀释和pH值变化，这可能会导致 向大脑线粒体输送氧气的障碍。 近红外光谱分析是一种新的实时脑监测方法 这提供了检测即将到来的危急大脑的可能性 缺氧/缺血。这项技术比目前的技术有明显的优势 间接监测大脑功能的方法，因为它有能力 定义通过以下途径将氧气成功输送到神经元线粒体 细胞色素aa3氧化还原状态的评估。这项研究将定义一个 标准连续法测定细胞色素Aa3还原的临界阈值 波近红外光谱学。这一脑损伤的门槛将 用一种新的侵入性近红外光谱方法进行验证 它测量了血红蛋白和线粒体的绝对变化。 氧合作用。在研究的第一阶段确定了关键的 损伤阈值，第二阶段的研究将测试第二 假设用近红外光谱进行实时监测可以 允许操作灌流参数，从而使神经损伤 是可以避免的。这项研究将阐明流动的机制 速率、温度、红细胞压积和pH相互作用决定神经元内 氧气输送。它还将演示近红外线的用途。 儿科手术中避免脑损伤的临床方法--波谱 心脏手术。

Children undergoing surgical repair of congenital cardiac anomalies are at significant risk of brain injury. In contrast to adults in whom the cause of brain injury during cardiac surgery is most commonly fixed or embolic atherosclerosis, in children the cause is most commonly global hypoxia/ischemia. The first hypothesis to be tested in the proposed study is that global cerebral hypoxia/ischemia results from definable, additive interactions of the extreme manipulations of perfusion parameters that are employed in pediatric cardiac surgery, namely extreme degrees of low perfusion flow, hypothermia, hemodilution and pH shifts, which can result in impaired oxygen delivery to cerebral mitochondria. Near infrared spectroscopy is a mew method of real-time brain monitoring that offers the potential to detect impending critical cerebral hypoxia/ischemia. This technique offers distinct advantages over current indirect methods of monitoring brain function because of its capacity to define successful delivery of oxygen to neuronal mitochondria through assessment of the redox state of cytochrome aa3. This study will define a critical threshold of cytochrome aa3 reduction using standard continuous wave near infrared spectroscopy. This threshold for cerebral injury will be validated using a novel invasive method of near infrared spectroscopy that measures absolute changes in both hemoglobin and mitochondrial oxygenation. After the first phase of the study has defined the critical threshold of injury, the second phase of the study will test the second hypothesis that real time monitoring with near infrared spectroscopy can allow manipulation of perfusion parameters such that neurological injury is avoided. The study will shed light on the mechanisms by which flow rate, temperature, hematocrit and pH interact to determine intraneuronal oxygen delivery. It also will demonstrate the utility of near infrared spectroscopy as a clinical method for avoid brain injury during pediatric cardiac surgery.