脑血流自动调节下限的无创测定方法研究

Study of noninvasive estimation the lower limit of cerebral autoregulation in human.

目的探讨脑血流自动调节下限(LLCA)的无创测定方法。方法选择青年健康志愿者32人,用经颅超声多普勒仪、无创血压监测仪监测和记录大脑中动脉的血流流速、桡动脉血压,用常规法和傅立叶变换法分别测定两组临界关闭压(CCP)和LLCA值。结果用常规法测定CCP有4例为负值,这4例经傅立叶变换法测定均为正值。常规法测定的LLCA值为(66.76±9.14)mmHg,傅立叶变换法测定的LLCA值为(60.79±10.12)mmHg,两者比较有显著性差异。结论临床无创测定LLCA宜用傅立叶变换法。

Objective To study the method of noinvasive estimation the lower limit of cerebral autoregulation (LLCA) in human. Methods TCD velocities in the middle cerebral artery and noninvasive blood pressure in the radial artery were continuous recorded in 32 healthy young volunteers. Critical closing pressure (CCP) and LLCA were calculated by two different methods: 1) linear extrapolation from normal heartbeat data; 2)first harmonic Fourier filtering of normal heartbeat data. Results Although 4 negative CCP values were elicited by the method of linear extrapolation from normal heartbeat data, 4 positive values were produced when the data of the same 4 volunteers were estimated with the use of a Fourier filter. LLCA calculated by the firet method(66.76 ± 9.14) mm Hg was higher than the LLCA estimated by the second method (60.79 ± 10.12) mm Hg. Conclusions Fourier transform method is recommended in the future studies of noninvasive estimation of the LLCA in human.