Department of Neurology (M.M., K.T., D.N., S.B.K., J.F., A.V., S.A., D.J.R., J.C., S.P.), Columbia University, NY.
Program in Hospital and Intensive Care Informatics of Department of Neurology (M.M., K.T., D.N., S.B.K., S.P.), Columbia University, NY.
Stroke. 2023 Jan;54(1):189-197. doi: 10.1161/STROKEAHA.122.040339. Epub 2022 Oct 31.
Targeting a cerebral perfusion pressure optimal for cerebral autoregulation (CPPopt) has been gaining more attention to prevent secondary damage after acute neurological injury. Brain tissue oxygenation (PbtO) can identify insufficient cerebral blood flow and secondary brain injury. Defining the relationship between CPPopt and PbtO after aneurysmal subarachnoid hemorrhage may result in (1) mechanistic insights into whether and how CPPopt-based strategies might be beneficial and (2) establishing support for the use of PbtO as an adjunctive monitor for adequate or optimal local perfusion.
We performed a retrospective analysis of a prospectively collected 2-center dataset of patients with aneurysmal subarachnoid hemorrhage with or without later diagnosis of delayed cerebral ischemia (DCI). CPPopt was calculated as the cerebral perfusion pressure (CPP) value corresponding to the lowest pressure reactivity index (moving correlation coefficient of mean arterial and intracranial pressure). The relationship of (hourly) deltaCPP (CPP-CPPopt) and PbtO was investigated using natural spline regression analysis. Data after DCI diagnosis were excluded. Brain tissue hypoxia was defined as PbtO <20 mmHg.
One hundred thirty-one patients were included with a median of 44.0 (interquartile range, 20.8-78.3) hourly CPPopt/PbtO2 datapoints. The regression plot revealed a nonlinear relationship between PbtO and deltaCPP (<0.001) with PbtO decrease with deltaCPP <0 mmHg and stable PbtO with deltaCPP ≥0mmHg, although there was substantial individual variation. Brain tissue hypoxia (34.6% of all measurements) was more frequent with deltaCPP <0 mmHg. These dynamics were similar in patients with or without DCI.
We found a nonlinear relationship between PbtO and deviation of patients' CPP from CPPopt in aneurysmal subarachnoid hemorrhage patients in the pre-DCI period. CPP values below calculated CPPopt were associated with lower PbtO. Nevertheless, the nature of PbtO measurements is complex, and the variability is high. Combined multimodality monitoring with CPP/CPPopt and PbtO should be recommended to redefine individual pressure targets (CPP/CPPopt) and retain the option to detect local perfusion deficits during DCI (PbtO), which cannot be fulfilled by both measurements interchangeably.
针对有利于脑自动调节的脑灌注压（CPPopt）的目标已逐渐受到重视，以防止急性神经损伤后的继发性损伤。脑组织氧合（PbtO）可识别脑血流不足和继发性脑损伤。定义蛛网膜下腔出血后 CPPopt 和 PbtO 之间的关系可能导致（1）对 CPPopt 为基础的策略是否可能有益以及如何有益的机制性理解，（2）支持将 PbtO 作为充分或最佳局部灌注的附加监测手段的证据。
我们对前瞻性收集的 2 个中心数据集中的伴有或不伴有迟发性脑缺血（DCI）的蛛网膜下腔出血患者进行了回顾性分析。CPPopt 计算为对应于最低压力反应性指数（平均动脉和颅内压的移动相关系数）的脑灌注压（CPP）值。使用自然样条回归分析研究了（每小时）ΔCPP（CPP-CPPopt）与 PbtO 的关系。排除 DCI 诊断后的数据。脑组织缺氧定义为 PbtO<20mmHg。
共纳入 131 例患者，中位数每小时 CPPopt/PbtO2 数据点为 44.0（四分位间距 20.8-78.3）。回归图显示 PbtO 与ΔCPP 之间存在非线性关系（<0.001），ΔCPP<0mmHg 时 PbtO 降低，ΔCPP≥0mmHg 时 PbtO 稳定，尽管存在较大的个体差异。ΔCPP<0mmHg 时，脑组织缺氧（所有测量值的 34.6%）更为常见。在有或无 DCI 的患者中，这些动态变化相似。
我们发现，在 DCI 前阶段，蛛网膜下腔出血患者的 PbtO 与 CPP 与 CPPopt 的偏差之间存在非线性关系。低于计算 CPPopt 的 CPP 值与较低的 PbtO 相关。然而，PbtO 测量的性质复杂，变异性高。应推荐联合使用 CPP/CPPopt 和 PbtO 的多模态监测来重新定义个体压力目标（CPP/CPPopt），并保留在 DCI 期间检测局部灌注不足（PbtO）的选项，这两种测量都无法替代。
