Chiu C C, Yeh S J
Institute of Automatic Control Engineering, Feng Chia University, ROC, Taichung, Taiwan.
Comput Biol Med. 2001 Nov;31(6):471-80. doi: 10.1016/s0010-4825(01)00015-4.
Time domain cross-correlation analysis of pre-filtered mean arterial blood pressure (MABP) and mean cerebral blood flow velocity (MCBFV) was applied to assess the cerebral autoregulation (CA). Beat-to-beat time series of spontaneous arterial blood pressure and cerebral blood flow velocity were obtained from 13 young normal volunteers with the Finapres device and the transcranial Doppler for periods of approximately 5 min in the supine position. Cross-correlation functions (CCFs) were estimated using a 64 beat wide moving window. Mean CCF patterns were obtained for each subject and for the entire population. The MABP and MCBFV signals were bandpass filtered in the very low-frequency range (VLF, 0.015-0.07 Hz), low-frequency range (LF, 0.07-0.15 Hz) and high-frequency range (HF, 0.15-0.40 Hz) before applying CCF for the purpose of studying the effect of different bandwidths on the resulting mean CCFs. Results revealed that the corresponding time lags of the peak values of the MABP-MCBFV CCFs increased significantly between the LF and HF frequency ranges (LF: -1.20+/-0.91 s, HF: -0.07+/-0.42 s,p < 0.001; paired sign test). The left-shift (negative lag) of the CCF peak between MABP and MCBFV is a result of the phase-lead property. The increasing time lag of the CCF peak indicated evidence of the autoregulatory disturbance. The CCF of pre-filtered spontaneous MABP and MCBFV could be a useful tool to estimate the CA dynamic response.
应用预滤波的平均动脉血压（MABP）和平均脑血流速度（MCBFV）的时域互相关分析来评估脑自动调节（CA）。使用Finapres设备和经颅多普勒从13名年轻正常志愿者中获取仰卧位约5分钟的逐搏动脉血压和脑血流速度的时间序列。使用64拍宽的移动窗口估计互相关函数（CCF）。获得每个受试者和整个人群的平均CCF模式。在应用CCF之前，将MABP和MCBFV信号在极低频范围（VLF，0.015 - 0.07 Hz）、低频范围（LF，0.07 - 0.15 Hz）和高频范围（HF，0.15 - 0.40 Hz）进行带通滤波，以研究不同带宽对所得平均CCF的影响。结果显示，MABP - MCBFV CCF峰值的相应时间滞后在低频和高频范围之间显著增加（低频：-1.20±0.91秒，高频：-0.07±0.42秒，p < 0.001；配对符号检验）。MABP和MCBFV之间CCF峰值的左移（负滞后）是相位超前特性的结果。CCF峰值时间滞后的增加表明存在自动调节紊乱的证据。预滤波的自发MABP和MCBFV的CCF可能是估计CA动态反应的有用工具。
