Continuous Measurement in Neurocritical Care of Cerebral Blood Flow (CBF) Calculated from ICP and Central Venous Pressure.

IF 3.2 Q2 CLINICAL NEUROLOGY
Erik Ryding
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Abstract

Background/Objectives: In neurocritical care, usually, the only continuous measurement of brain pathophysiology is intracranial pressure (ICP). The objective of this study was to find the relationship between cerebral blood flow (CBF) and parameters usually measured in neurocritical care, mainly central venous pressure and ICP. Methods: If the venous outflow of the CBF is considered, the CBF is controlled only by two parameters, the rICP (the ICP minus the venous blood pressure in the venous sinus at its outflow) and the Rv (the flow resistance of the soft-walled veins). For the rICP, the sinus blood pressure can be calculated from the central venous pressure (measured at the same horizontal level as the ICP) and the cervical venous flow resistance. For the Rv, the systolic ICP increase indicates the systolic arterial inflow volume, which then flows out before the diastole. The mean ICP increase divided by the mean outflow of the increased blood volume gives the Rv. This method of calculating the CBF by dividing the rICP by the Rv was named CBF(1). For validation of CBF(1), data from nine subjects in an open study were used. The data were ICP and MR blood flow measurements of arterial inflow and jugular vein outflow. Since the rICP, Rv, and CBF were unknown, an iterative method was needed to calculate these parameters. Results: The observed Rv and rICP values showed a close correlation, which indicated that CBF was dependant on the rICP only. Consequently, the comparison between the data in the study of the nine subjects, and the calculated values from CBF(1), boiled down to a comparison between the supine ICP values and the calculated rICP. The comparison showed that the rICP and supine ICP had highly significant similarity, and that the CBF(1) method was validated. Conclusions: A method for CBF measurement from ICP data in neurocritical care was found.

连续测量颅内压和中心静脉压计算的脑血流(CBF)在神经危重症护理中的应用。
背景/目的:在神经危重症护理中,通常唯一连续的脑病理生理测量是颅内压(ICP)。本研究的目的是发现脑血流量(CBF)与神经危重症监护中通常测量的参数,主要是中心静脉压和ICP之间的关系。方法:如果考虑血流的静脉流出,血流仅由两个参数控制,即ICP (ICP减去流出静脉窦的静脉压)和Rv(软壁静脉的流动阻力)。对于ICP,可以通过中心静脉压(与ICP在同一水平水平测量)和颈静脉血流阻力计算窦内血压。对于右心室,收缩期ICP升高表明收缩期动脉流入容量,然后在舒张期之前流出。平均ICP增量除以增加的血容量的平均流出量得到Rv。这种用rICP除以Rv计算CBF的方法被命名为CBF(1)。为了验证CBF(1),使用了一项开放研究中9名受试者的数据。数据为动脉流入和颈静脉流出的ICP和MR血流量测量。由于rICP、Rv和CBF是未知的,因此需要采用迭代方法计算这些参数。结果:观察到的Rv值与rICP值密切相关,表明脑血流仅依赖于rICP。因此,9名受试者的研究数据与CBF(1)计算值之间的比较归结为仰卧位ICP值与计算的ICP值之间的比较。结果表明,颅内压与仰卧颅内压具有高度显著的相似性,验证了CBF(1)方法的有效性。结论:发现了一种从神经危重症监护的ICP数据中测量CBF的方法。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Neurology International
Neurology International CLINICAL NEUROLOGY-
CiteScore
3.70
自引率
3.30%
发文量
69
审稿时长
11 weeks
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