Department of Biomedical Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, Canada.
Undergraduate Engineering, Price Faculty of Engineering, University of Manitoba, Winnipeg, Canada.
Physiol Meas. 2023 Jul 24;44(7). doi: 10.1088/1361-6579/acdfb6.
Cerebral blood vessels maintaining relatively constant cerebral blood flow (CBF) over wide range of systemic arterial blood pressure (ABP) is referred to as cerebral autoregulation (CA). Impairments in CA expose the brain to pressure-passive flow states leading to hypoperfusion and hyperperfusion. Cerebrovascular reactivity (CVR) metrics refer to surrogate metrics of pressure-based CA that evaluate the relationship between slow vasogenic fluctuations in cerebral perfusion pressure/ABP and a surrogate for pulsatile CBF/cerebral blood volume. We performed a systematically conducted scoping review of all available human literature examining the association between continuous CVR between more than one brain region/channel using the same CVR index. In all the included 22 articles, only handful of transcranial doppler (TCD) and near-infrared spectroscopy (NIRS) based metrics were calculated for only two brain regions/channels. These metrics found no difference between left and right sides in healthy volunteer, cardiac surgery, and intracranial hemorrhage patient studies. In contrast, significant differences were reported in endarterectomy, and subarachnoid hemorrhage studies, while varying results were found regarding regional disparity in stroke, traumatic brain injury, and multiple population studies. Further research is required to evaluate regional disparity using NIRS-based indices and to understand if NIRS-based indices provide better regional disparity information than TCD-based indices.
大脑血管在全身动脉血压（ABP）广泛变化范围内保持相对恒定的脑血流（CBF），这被称为脑自动调节（CA）。CA 的损害使大脑暴露于压力被动血流状态，导致灌注不足和过度灌注。脑血管反应性（CVR）指标是基于压力的 CA 的替代指标，用于评估脑灌注压/ABP 的缓慢血管源性波动与脉动 CBF/脑血容量的替代指标之间的关系。我们对所有可用的人类文献进行了系统的范围审查，这些文献检查了使用相同 CVR 指数的多个脑区/通道之间连续 CVR 的相关性。在所有纳入的 22 篇文章中，只有少数经颅多普勒（TCD）和近红外光谱（NIRS）基于指标仅计算了两个脑区/通道。这些指标在健康志愿者、心脏手术和脑出血患者的研究中，在左右两侧没有发现差异。相比之下，在颈动脉内膜切除术和蛛网膜下腔出血的研究中报告了显著差异，而在中风、创伤性脑损伤和多人群研究中则发现了区域差异的不同结果。需要进一步研究使用基于 NIRS 的指数评估区域差异，并了解基于 NIRS 的指数是否比基于 TCD 的指数提供更好的区域差异信息。
