The repeatability of cerebral autoregulation assessment using sinusoidal lower body negative pressure
The repeatability of cerebral autoregulation assessment using sinusoidal lower body negative pressure
复制标题
DOI：
10.1088/0967-3334/23/1/307
复制
发表时间：
2002-02-01
影响因子：
3.2
通讯作者：
Murrills, AJ
中科院分区：
文献类型：
--
作者：
Birch, AA;Neil-Dwyer, G;Murrills, AJ
血压的强制性周期性变化会产生脑血流速度的类似变化。压力和速度波形的幅度和相位指示大脑自动调节的动态响应。速度的相位领先于压力;相位差越大，自动调节响应越快。已经采用了各种技术来振荡动脉血压，但是测量再现性很差。本研究的目的是评估正弦下体负压用于改变血压时相位测量的可重复性，5名健康志愿者在两个真空水平下进行了评估，每次8次。每次测量保持12 s正弦周期5 min，在振荡频率下测定血压和大脑中动脉血流速度的傅立叶分量，血流速度的相位始终领先于血压。真空度较强时的平均相位差为42+/-13度，真空度较弱时的平均相位差为36+/-42度。给出的变异是从单因素方差分析估计的受试者内标准差。正弦下体负压是研究自动调节的有用刺激;它比其他方法具有优势。高真空显示出良好的再现性，但对于患者使用来说太不舒服。
A forced periodic variation in blood pressure produces a similar variation in cerebral blood velocity. The amplitudes and phases of the pressure and velocity waveforms are indicative of the dynamic response of the cerebral autoregulation. The phase of the velocity leads the pressure; the greater the phase difference the faster the autoregulation response. Various techniques have been employed to oscillate arterial blood pressure but measurement reproducibility has been poor. The purpose of this study was to assess the reproducibility of phase measurements when sinusoidal lower body negative pressure is used to vary blood pressure.Five healthy volunteers were assessed at two vacuum levels on each of eight visits. For each measurement a 12 s sinusoidal cycle was maintained for 5 min. The Fourier components of blood pressure and the middle cerebral artery velocity were determined at the oscillation frequency.The phase of velocity consistently led the pressure. The mean phase difference was 42+/-13degrees for the stronger vacuum and 36+/-42degrees for the weaker vacuum. The variation given is the within-subjects standard deviation estimated from a one-way analysis of variance.Sinusoidal lower body negative pressure is a useful stimulus for investigating autoregulation; it has advantages over other methods. High vacuums show good reproducibility but are too uncomfortable for patient use.