Oscillatory cerebral hemodynamics - the macro- vs. microvascular level
Oscillatory cerebral hemodynamics - the macro- vs. microvascular level
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DOI：
10.1016/j.jns.2006.07.011
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发表时间：
2006-12-01
影响因子：
4.4
通讯作者：
Hetzel, Andreas
中科院分区：
文献类型：
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作者：
Reinhard, Matthias;Wehrle-Wieland, Elisabeth;Hetzel, Andreas
血压(BP)和大脑中动脉血流速度(MCAFV)波动之间的相移反映了大脑持续的自我调节作用。目前尚不清楚用近红外光谱(NIRS)评估的皮质血流动力学(微血管水平)是否存在类似的相移，以及病理条件的影响。本研究探讨了38例健康老年人和28例单侧重度梗阻性颈动脉疾病患者的血压、MCAFV和近红外光谱参数振荡之间的时相关系。用手指体积描记法无创记录血压。呼吸频率为6次/min时，所有血流动力学参数均出现稳定的0.1 Hz振荡。基本结果是：(1)BP诱发的皮质微血管振荡(NIR)遵循宏大血管振荡(MCAFV)的80-90度时相(对应于S在0.1赫兹时的2-2.5度)，最可能反映一种穿越时间现象；(2)氧和脱氧血红蛋白因此在反相振荡；(3)颈动脉阻塞时的血流动力学损害导致(A)相对于BP的NIRS振荡延迟，这与MCAFV对BP的时相缩短高度相关；(B)氧/脱氧血红蛋白反相脱钩至240度。由于大脑自身调节作用和循环传递时间的原因，皮质血流动力学对血压振荡的反应遵循特定的时相关系。随着血流动力学受损，如单侧颈动脉阻塞，这些时相显著改变，反映了自我调节的紊乱。2006 Elsevier B.V.学位保留所有权利。
The phase shift between oscillations of blood pressure (BP) and Doppler middle cerebral artery flow velocity (MCAFV) reflects continuous cerebral autoregulatory action. It is not known whether a similar phase shift exists for cortical hemodynamics ('microvascular level') assessed by near infrared spectroscopy (NIRS) and what the effects are of pathological conditions. This study investigates the phase relations between oscillations of BP, MCAFV and NIRS parameters in 38 healthy older adults and 28 patients with unilateral severe obstructive carotid disease. BP was recorded noninvasively by finger plethysmography. Stable 0.1 Hz oscillations of all hemodynamic parameters were induced by regular breathing at a rate of 6/min. Basic results were that: (1) BP-induced cortical microvascular oscillations (NIRS) follow those of rnacrovascular oscillations (MCAFV) with a phase of 80-90 degrees (corresponding to 2-2.5 s at 0.1 Hz), most likely reflecting a transit time phenomenon; (2) oxy-and deoxyhemoglobin thereby oscillate in counterphase; (3) hemodynamic compromise in carotid obstruction leads to (a) delayed NIRS oscillations in comparison to BP which are highly correlated to a shorter phase lead of MCAFV against BP and (b) a decoupling of the oxy-/deoxyhemoglobin counterphase to 240 degrees. Cortical hemodynamic responses to BP oscillations follow specific phase relationships due to cerebral autoregulatory action and circulatory transit times. With hemodynamic impairment, as in unilateral carotid obstruction, these phases are significantly changed reflecting disturbed autoregulation. degrees 2006 Elsevier B.V. All rights reserved.