Govindan Rathinaswamy B, Brady Ken M, Massaro An N, Perin Jamie, Jennings Jacky M, DuPlessis Adre J, Koehler Raymond C, Lee Jennifer K
Fetal Medicine Institute, Children's National Health System, Washington, District of Columbia, USA.
The George Washington University School of Medicine, Washington, District of Columbia, USA.
Dev Neurosci. 2019 May 2:1-13. doi: 10.1159/000499425.
The optimal method to detect impairments in cerebrovascular pressure autoregulation in neonates with hypoxic-ischemic encephalopathy (HIE) is unclear. Improving autoregulation monitoring methods would significantly advance neonatal neurocritical care.
We tested several mathematical algorithms from the frequency and time domains in a piglet model of HIE, hypothermia, and hypotension. We used laser Doppler flowmetry and induced hypotension to delineate the gold standard lower limit of autoregulation (LLA). Receiver operating characteristics curve analyses were used to determine which indices could distinguish blood pressure above the LLA from that below the LLA in each piglet.
Phase calculation in the frequency band with maximum coherence, as well as the correlation between mean arterial pressure (MAP) and near-infrared spectroscopy relative total tissue hemoglobin (HbT) or regional oxygen saturation (rSO2), accurately discriminated functional from dysfunctional autoregulation. Neither hypoxia-ischemia nor hypothermia affected the accuracy of these indices. Coherence alone and gain had low diagnostic value relative to phase and correlation.
Our findings indicate that phase shift is the most accurate component of autoregulation monitoring in the developing brain, and it can be measured using correlation or by calculating phase when coherence is maximal. Phase and correlation autoregulation indices from MAP and rSO2 and vasoreactivity indices from MAP and HbT are accurate metrics that are suitable for clinical HIE studies.
目前尚不清楚检测缺氧缺血性脑病（HIE）新生儿脑血管压力自动调节功能受损的最佳方法。改进自动调节监测方法将显著推动新生儿神经重症监护的发展。
我们在HIE、低温和低血压仔猪模型中测试了频域和时域的几种数学算法。我们使用激光多普勒血流仪并诱导低血压来确定自动调节下限（LLA）的金标准。采用受试者工作特征曲线分析来确定哪些指标可以区分每只仔猪高于LLA的血压和低于LLA的血压。
最大相干频段的相位计算，以及平均动脉压（MAP）与近红外光谱相对总组织血红蛋白（HbT）或局部氧饱和度（rSO2）之间的相关性，准确地区分了功能性和功能失调性自动调节。缺氧缺血和低温均未影响这些指标的准确性。相对于相位和相关性，单独的相干性和增益具有较低的诊断价值。
我们的研究结果表明，相移是发育中大脑自动调节监测中最准确的组成部分，可以使用相关性或在相干性最大时通过计算相位来测量。来自MAP和rSO2的相位和相关性自动调节指标以及来自MAP和HbT的血管反应性指标是适用于临床HIE研究的准确指标。
