颅内压低频分析

Analysis of the low frequency components of the intracranial pressure

目的 :临床和基础研究发现 ,颅内压存在波动 ,本工作通过动物实验模拟颅高压并研究颅内压的波动。实验方法 :14条犬安置硬膜外球囊并注液制成颅高压模型 ,通过改变球囊内液体量来改变颅高压程度和颅内容积 ,由压力传感器持续记录相应压力。结果 :对颅内压、腰区脑脊液压分别进行FFT分析 ,发现都存在一个约为 0 2Hz的波动 ,该频率既不是心率 (3Hz左右 )也不是呼吸频率 (0 4Hz) ,记为M波。分析表明 :1)正常情况下 ,M波并不出现 ;2 )实验开始阶段 ,不出现M波 ,当颅内压超过一定压力水平时 ,M波出现。随后的药物干预实验显示 ,采用迷走神经阻断药阿托品能明显抑制M波 ,而交感神经阻断药心得安效果不明显 。

Aim:The clinical studies show that the intracranial pressure(ICP)is not a static pressure.This work was planned to simulate high intracranial pressure by animal experiment and investigate the frequency of the ICP.Methods:Fourteen dogs were anesthetized before the operatuion.A small rubber balloon for changing the ICP was placed in the epidural space through a drill hole in the skull.Pressure transducers were arranged to monitor,and pressures were recorded.Spectral analysis of the collected ICP、LCP(the pressure in the lumbar subarachnoid cavity)data was performed later.Results:The frequency spectrum of each pressure waveform was calculated using an algorithm for Fast Fourier Transform.The analysis showed that there was a special spectral component roughly 0 2Hz in the waveform when the ICP exceeded a certain level.The special spectral component didn't associate with respiration(0 4Hz)and the cardiac beat(3Hz).It was named the M wave.1)Under normal condition,the M wave did not appear.2)At the beginning of the experiment,the M wave did not appear,when ICP exceeded a certain level,it appeared.The following experiments suggested that the M wave might relate to the cerebrovascular autoregulation.