Assessment of cerebral autoregulation: the quandary of quantification
Assessment of cerebral autoregulation: the quandary of quantification
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DOI：
10.1152/ajpheart.00328.2012
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发表时间：
2012-09-01
影响因子：
4.8
通讯作者：
Rickards, C. A.
中科院分区：
文献类型：
--
作者：
Tzeng, Y. C.;Ainslie, P. N.;Rickards, C. A.
曾亚春，安斯利PN，库克WH，Peeble KC，Willie CK，Macrae BA，Smirl JD，Horsman HM，Rickards CA。大脑自我调节的评估：量化的困境。Am J Physiol心脏圈Physiol 303：H658-H671,2012。2012年7月20日首次出版；doi：10.1152/ajpheart.00328.2012。-我们评估了脑自动调节(CA)常用指标的收敛有效性，以确定这些指标可互换使用的程度。为了检验低频(0.07-0.2赫兹)和甚低频(0.02-0.07赫兹)传递函数相干性、相位、增益和归一化增益之间的对象间关系，我们对105名个体的自发性血压和大脑中动脉血流速度记录进行了回溯性传递函数分析。我们描述了自发传递函数指标与调节指数和自身调节指数的比率之间的关系(n=29)，这些指标来自双侧大腿袖带收缩试验。此外，我们分析了29名受试者(n=29)的数据，这些受试者接受了重复的蹲-立方案，以确定强迫血压波动期间传递函数指标之间的关系。最后，对16例呼气末二氧化碳分压(PETCO2)阶跃变化的受试者的数据进行分析，以确定传递函数指标是否能够可靠地跟踪个体内CA的调制。CA指标一般不相关或仅显示出弱到中等的相关性。PETCO2的变化与一致性正相关[低频：贝塔=0.0065个任意单位(AU)/毫米汞和甚低频：贝塔=0.011 AU/毫米汞，均P<；0.01]，与相位(低频：贝塔=-0.026拉德/毫米汞和甚低频：贝塔=-0.018拉德/毫米汞)和归一化增益(低频：贝塔=-0.042%/毫米汞(2)和甚低频：贝塔=-0.013%/毫米汞(2)，P<；0.01)负相关。然而，PETCO2与增益呈正相关(低频：β=0.0070 cm·s(-1).mm Hg(-2)，P<；0.05；甚低频：β=0.014 cm·s(-1).mm Hg(-2)，P<；0.01)。因此，在PETCO2变化过程中，LF时相与LF增益呈负相关(β=-0.29 cm·s(-1)·mm Hg(-1)·rad(-1)，P<；0.01)，而与LF归一化增益呈正相关(beta=1.3%mm Hg(-1)/rad，P<；0.01)。这些发现共同表明，只有选定的CA指标可以互换使用，对这些指标的解释应该谨慎进行。
Tzeng YC, Ainslie PN, Cooke WH, Peebles KC, Willie CK, MacRae BA, Smirl JD, Horsman HM, Rickards CA. Assessment of cerebral autoregulation: the quandary of quantification. Am J Physiol Heart Circ Physiol 303: H658-H671, 2012. First published July 20, 2012; doi:10.1152/ajpheart.00328.2012.-We assessed the convergent validity of commonly applied metrics of cerebral autoregulation (CA) to determine the extent to which the metrics can be used interchangeably. To examine between-subject relationships among low-frequency (LF; 0.07-0.2 Hz) and very-low-frequency (VLF; 0.02-0.07 Hz) transfer function coherence, phase, gain, and normalized gain, we performed retrospective transfer function analysis on spontaneous blood pressure and middle cerebral artery blood velocity recordings from 105 individuals. We characterized the relationships (n = 29) among spontaneous transfer function metrics and the rate of regulation index and autoregulatory index derived from bilateral thigh-cuff deflation tests. In addition, we analyzed data from subjects (n = 29) who underwent a repeated squat-to-stand protocol to determine the relationships between transfer function metrics during forced blood pressure fluctuations. Finally, data from subjects (n = 16) who underwent step changes in end-tidal PCO2 (PETCO2) were analyzed to determine whether transfer function metrics could reliably track the modulation of CA within individuals. CA metrics were generally unrelated or showed only weak to moderate correlations. Changes in PETCO2 were positively related to coherence [LF: beta = 0.0065 arbitrary units (AU)/mmHg and VLF: beta = 0.011 AU/mmHg, both P < 0.01] and inversely related to phase (LF: beta = -0.026 rad/mmHg and VLF: beta = -0.018 rad/mmHg, both P < 0.01) and normalized gain (LF: beta = -0.042%/mmHg(2) and VLF: beta = -0.013%/ mmHg(2), both P < 0.01). However, PETCO2 was positively associated with gain (LF: beta = 0.0070 cm.s(-1.)mmHg(-2), P < 0.05; and VLF: beta = 0.014 cm.s(-1).mmHg(-2), P < 0.01). Thus, during changes in PETCO2, LF phase was inversely related to LF gain (beta = -0.29 cm.s(-1).mmHg(-1).rad(-1), P < 0.01) but positively related to LF normalized gain (beta = 1.3% mmHg(-1)/rad, P < 0.01). These findings collectively suggest that only select CA metrics can be used interchangeably and that interpretation of these measures should be done cautiously.