Academic Neurosurgical Unit, University of Cambridge Clinical School, Cambridge, UK.
Stroke. 2010 Sep;41(9):1963-8. doi: 10.1161/STROKEAHA.109.577320. Epub 2010 Jul 22.
In patients with subarachnoid hemorrhage, the assessment of cerebral autoregulation aids in prognosis as well as detection of vasospasm. Mx is a validated index of cerebral autoregulation based on measures of cerebral perfusion pressure and mean flow velocity on transcranial Doppler but is impractical for longer-term monitoring. Near-infrared spectroscopy is noninvasive and suitable for continuous monitoring of cerebral tissue oxygenation using the Tissue Oxygenation Index. In this study, we compared near-infrared spectroscopy-based indices of cerebral autoregulation (TOx) with Mx in patients with subarachnoid hemorrhage.
Arterial blood pressure, intracranial pressure, mean flow velocity, and Tissue Oxygenation Index were recorded. Mx and TOx were calculated as moving correlation coefficients between 10-second averaged values of cerebral perfusion pressure and mean flow velocity and between cerebral perfusion pressure and Tissue Oxygenation Index. We also calculated TOxA, the moving correlation coefficient between arterial blood pressure and Tissue Oxygenation Index.
Fifty-one recording sessions were performed in 27 patients with subarachnoid hemorrhage with a total duration of 62.5 hours. Correlations of Mx and TOx over time varied markedly among individual recordings. However, time-averaging over the entire recording interval in each of the 51 recordings, we found correlations between Mx and TOx and between Mx and TOxA were highly significant. This correlation was even stronger after correction for multiple sampling for each patient, reaching r=0.81 for Mx and TOx and r=0.72 for Mx and TOxA.
Near-infrared spectroscopy can be used to continuously assess cerebral autoregulation in adults after subarachnoid hemorrhage.
在蛛网膜下腔出血患者中，脑自动调节的评估有助于预后和血管痉挛的检测。Mx 是一种基于经颅多普勒测量脑灌注压和平均血流速度的脑自动调节的验证指数，但不适合长期监测。近红外光谱是一种非侵入性的方法，适合使用组织氧合指数连续监测脑组织氧合。在这项研究中，我们比较了蛛网膜下腔出血患者基于近红外光谱的脑自动调节指数（TOx）与 Mx。
记录动脉血压、颅内压、平均血流速度和组织氧合指数。Mx 和 TOx 分别计算为脑灌注压和平均血流速度和脑灌注压与组织氧合指数 10 秒平均值之间的移动相关系数。我们还计算了 TOxA，即动脉血压与组织氧合指数之间的移动相关系数。
在 27 例蛛网膜下腔出血患者中进行了 51 次记录，总持续时间为 62.5 小时。个体记录之间的 Mx 和 TOx 的时间相关性差异很大。然而，在每个患者的 51 个记录中的整个记录间隔的时间平均化中，我们发现 Mx 和 TOx 之间以及 Mx 和 TOxA 之间的相关性非常显著。在对每个患者进行多次采样校正后，这种相关性更强，达到 Mx 和 TOx 之间的 r=0.81，以及 Mx 和 TOxA 之间的 r=0.72。
近红外光谱可用于连续评估蛛网膜下腔出血后成人的脑自动调节。
