VASOREACTIVITY OF CEREBRAL HEMODYNAMICS-NEONATES WITH CONGENITAL HEART DEFECTS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 新生儿心脏手术幸存者的神经发育受损结局已观察到 先天性心脏缺陷。先前有证据表明，术前脑部检查的重要性 幸福感取决于观察到的结果。此外，众所周知，手术参数 包括心脏旁路、深度降温和停搏需要通过床边实时优化 监控。一个很大程度上无法获得的关键参数是脑血流量(CBF)。我们有 近几年发展起来的无创、连续测量的漫相关光谱技术 相对脑血流量。在这项工作中，我们报告了它在新生儿中的临床应用的第一个结果 将其与漫反射光谱(DOS)相结合，用于测量血液氧合和 脑氧代谢。在这项双队列研究中，患有严重先天性心脏病的新生儿 在手术前进行测量，以评估大脑的二氧化碳反应性和 自动调节。第一个队列(n=44)是在长期高碳酸血症期间测量的 MRI磁体和DCS测量与动脉自旋标记MRI测量结果进行了对比验证 CBF显示两种方法具有较好的一致性。二氧化碳反应性的损害不是 由于文献中报告的大范围的二氧化碳反应性值和样本大小而观察到。 目前正在招募第二个队列(n=18)，以进行更广泛的监测，包括 术前准备时间及术后复查结果的统计学比较 结果衡量标准。我们已经监测了这一新的脑血流和氧合变化 使用床边光学技术的心脏手术后立即进行12小时的队列研究。我们是 大脑自我调节受损的投资期，即脑血流的时间段 和平均动脉压高度相关。此外，手术后一周，受试者 接受手术后解剖核磁共振扫描，以确定是否有缺氧缺血的程度 脑白质损伤。 这项研究的第三阶段旨在调查这些患者的绝对光学性质，以便 更准确地量化组织氧饱和度(StO2)和大脑代谢率的变化 氧气提取(CMRO2)。 目前，我们根据已发表的文献对这些婴儿的基线光学性质进行了假设 非常稀疏的值，以便近似StO2和CMRO2。我们将设计和 实施新的光学探头来评估每个患者的这些特性，作为我们现有的 最终评估StO2和CMRO2的方案。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Impaired neurodevelopmental outcome has been observed for survivors of neonatal heart surgery for congenital heart defects. There is prior evidence indicating the importance of preoperative cerebral well-being on the observed outcome. Furthermore, it is well known that the surgical parameters which include cardiac by-pass, deep-cooling and arrest need to be optimized via real-time, bed-side monitoring. A crucial parameter that is largely inaccessible is the cerebral blood flow (CBF). We have recently developed diffuse correlation spectroscopy (DCS) for non-invasive, continuous measurement of relative CBF. In this work, we report our first results from its clinical application to neonates where it was combined with diffuse optical spectroscopy (DOS) for measurement of blood oxygenation and cerebral oxygen metabolism. In this two-cohort study, neonates with severe congenital heart defects scheduled for cardiac surgery were measured preoperatively to assess cerebral C02 reactivity and autoregulation. The first cohort (n=44) was measured during an extended period of hypercapnia in the MRI magnet and DCS measurement was validated against arterial spin-labeling MRI measure of CBF showing good agreement between two methods. An impairment of C02 reactivity was not observed due to large range of C02 reactivity values reported in the literature and the sample size. The second cohort is now being recruited (n=18) for a more extended monitoring including the preoperative preparation period and statistically comparing the findings with the post-operative outcome measures. We have monitored cerebral blood flow and oxygenation changes in this new cohort for 12 hours immediately following cardiac surgery using bedside optical techniques. We are investing periods of damaged cerebral autoregulation, i.e. periods of time in which cerebral blood flow and mean arterial pressure are highly correlated. Additionally, a week after surgery, the subjects undergo a post-surgical anatomical MRI scan to determine the extent, if any, of hypoxic-ischemic white matter injury. Phase 3 of this study aims to investigate absolute optical properties of these patients in order to more accurately quantify changes in tissue oxygen saturation (StO2), and cerebral metabolic rate of oxygen extraction (CMRO2). Currently, we make assumptions on baseline optical properties of these infants based on published values, which are very sparse, in order to approximate StO2 and CMRO2. We will design and implement a new optical probe to assess these properties on each patient as part of our existing protocol to definitively evaluate StO2 and CMRO2.