Transcranial Doppler Pulsatility Index: Not an Accurate Method to Assess Intracranial Pressure
Transcranial Doppler Pulsatility Index: Not an Accurate Method to Assess Intracranial Pressure
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DOI：
10.1227/01.neu.0000369519.35932.f2
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发表时间：
2010-06-01
期刊：
影响因子：
4.8
通讯作者：
Koskinen, Lars-Owe
中科院分区：
文献类型：
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作者：
Behrens, Anders;Lenfeldt, Niklas;Koskinen, Lars-Owe
背景：经颅多普勒超声（TCD）评估颅内血流速度已被建议准确确定颅内压（ICP）。目的：我们试图在使用预定压力水平的交流脑脊液系统患者中验证该方法。方法：10例患者进行腰椎灌注试验，应用4 ~ 5个预设ICP水平。在每个水平上，通过TCD测量血流速度来测定大脑中动脉的脉搏指数（PI）。脑实质内传感器同时测量颅内压。ICP与PI采用相关分析进行比较。为了进一步了解ICP-PI关系，用计算机模拟了颅内动力学的数学模型。结果：ICP-PI回归方程基于8例患者的数据。2例患者未获得听得多普勒信号。公式为ICP = 23*PI + 14 （R-2 = 0.22, P < 0.01, N = 35）。平均ICP为20毫米汞柱的95%置信区间为-3.8至43.8毫米汞柱。个别回归系数为42至90，偏移量为-32至+3。数学模拟表明，血管顺应性、自动调节和动脉压力的变化对ICP-PI关系有严重影响。结论：体内实验结果表明PI不是ICP的可靠预测指标。数学模拟表明，这是由生理参数的变化引起的。
BACKGROUND: Transcranial Doppler sonography (TCD) assessment of intracranial blood flow velocity has been suggested to accurately determine intracranial pressure (ICP).OBJECTIVE: We attempted to validate this method in patients with communicating cerebrospinal fluid systems using predetermined pressure levels.METHODS: Ten patients underwent a lumbar infusion test, applying 4 to 5 preset ICP levels. On each level, the pulsatility index (PI) in the middle cerebral artery was determined by measuring the blood flow velocity using TCD. ICP was simultaneously measured with an intraparenchymal sensor. ICP and PI were compared using correlation analysis. For further understanding of the ICP-PI relationship, a mathematical model of the intracranial dynamics was simulated using a computer.RESULTS: The ICP-PI regression equation was based on data from 8 patients. For 2 patients, no audible Doppler signal was obtained. The equation was ICP = 23*PI + 14 (R-2 = 0.22, P < .01, N = 35). The 95% confidence interval for a mean ICP of 20 mm Hg was -3.8 to 43.8 mm Hg. Individually, the regression coefficients varied from 42 to 90 and the offsets from -32 to +3. The mathematical simulations suggest that variations in vessel compliance, autoregulation, and arterial pressure have a serious effect on the ICP-PI relationship.CONCLUSIONS: The in vivo results show that PI is not a reliable predictor of ICP. Mathematical simulations indicate that this is caused by variations in physiological parameters.