人脑循环临界关闭压、有效脑灌注压无创测定方法的研究

Methods of noninvasively estimating critical closing pressure and cerebral perfusion pressure in human

目的探讨人脑循环临界关闭压(criticalclosingpressure,CCP)和有效脑灌注压(cerebral perfusionpressure,CPP)的无创测定方法。方法选择符合入组要求的青年健康志愿者32例,应用经颅超声多普勒、无创血压监测仪持续记录大脑中动脉血流流速、桡动脉血压,用动态压力流量关系法中的常规法和傅立叶变换法分别测得两组CCP和CPP值。结果用常规法测定CCP有4例为负值,后经傅立叶变换法测定均为正值。常规法测定的CCP为(13.05±8.24)mmHg(1mmHg=0.133kPa),傅立叶变换法测定的CCP平均为(19.68±9.30)mmHg,较常规法测定值高(t=-2.904,P=0.005)。常规法测定的有效CPP为(66.76±9.14)mmHg,傅立叶变换法测定的有效CPP为(60.79±10.12)mmHg,两者差异有显著性意义(t=2.382,P=0.021)。结论临床无创测定CCP和有效CPP应该采用傅立叶变换法。

Objective To investigate the methods of noninvasively estimating critical closing pressure(CCP) and cerebral perfusion pressure(CPP) in human. Methods Transcranial Doppler velocities and noninvasive blood pressure in radial artery were continuously recorded in 32 healthy young volunteers. CCPs were calculated by two different methods: linear extrapolation from normal heartbeat data and first harmonic Fourier filtering of normal heartbeat data. Results Although 4 negative CCP values were elicited by the first method,four positive values were produced when the same data were estimated by the second method. CCP [((13.05)±(8.24))mm Hg(1 mm Hg=(0.133 )kPa)] calculated by the first method was lower than the CCP [((19.68)±(9.30))mm Hg ] estimated by the second method (t=(-2.904),P=(0.005)); CPP calculated by the first method [((66.76)±(9.14))mm Hg] was higher than the CPP [((60.79)±(10.12))mm Hg ] estimated by the second method (t=(2.382), P=(0.021)),respectively. Conclusions Fourier transform method is recommended in the future studies of noninvasive estimation of the CCP and CPP.