A MATHEMATICAL-MODEL OF THE RELATIONSHIP BETWEEN CEREBRAL BLOOD-VOLUME AND INTRACRANIAL-PRESSURE CHANGES - THE GENERATION OF PLATEAU WAVES
A MATHEMATICAL-MODEL OF THE RELATIONSHIP BETWEEN CEREBRAL BLOOD-VOLUME AND INTRACRANIAL-PRESSURE CHANGES - THE GENERATION OF PLATEAU WAVES
复制标题
DOI：
10.1007/bf02368459
复制
发表时间：
1991-01-01
影响因子：
3.8
通讯作者：
DIGIAMMARCO, P
中科院分区：
文献类型：
--
作者：
URSINO, M;DIGIAMMARCO, P
本文借助一个原始的数学模型，研究了颅内压、脑血容量、脑脊液动力学与脑血流调节机制的作用之间的关系。在建立模型时，特别强调再现大脑近端动脉和软脑膜小动脉的力学特性，以及它们对灌流压力和脑血流变化的主动调节反应。该模型可以满意地再现脑灌流压降低后脑血管扩张和脑血流调节的实验结果。此外，可以在不同的动脉降压水平下观察由自我调节引起的脑血容量变化对颅内压时间模式的影响。用正常参数值获得的结果表明，在自动调节的下限，当小动脉扩张达到最大时，脑血容量的增加可以引起显著的、一过性的颅内压升高。在病理条件下，颅内压和自我调节之间的这种对立可能会导致颅内系统的不稳定。特别是，对线性化系统的分析表明，脑脊液(CSF)重吸收的损害、颅内顺应性的降低以及脑血管床的高调节能力都是导致系统平衡变得不稳定(即，至少一个特征值的实部变为正值)的条件。因此，在上述情况下，数学模拟“大体上”显示出颅内压的周期性波动，这种波动在幅度、持续时间、频率和形状上与众所周知的Lundberg A波(或称高原波)非常相似。
The relationship between intracranial pressure (ICP), cerebral blood volume (CBV), cerebrospinal fluid dynamics, and the action of cerebral blood-flow (CBF) regulatory mechanisms is examined in this work with the help of an original mathematical model. In building the model, particular emphasis is placed on reproducing the mechanical properties of proximal cerebral arteries and small pial arterioles, and their active regulatory response to perfusion pressure and cerebral blood flow changes.The model allows experimental results on cerebral vessel dilatation and cerebral blood-flow regulation, following cerebral perfusion pressure decrease, to be satisfactorily reproduced. Moreover, the effect of cerebral blood volume changes-induced by autoregulatory adjustments-on the intracranial pressure time pattern can be examined at different levels of arterial hypotension.The results obtained with normal parameter values demonstrate that, at the lower limits of autoregulation, when dilatation of small arterioles becomes maximal, the increase in cerebral blood volume can cause a significant, transient increase in intracranial pressure. This antagonism between intracranial pressure and autoregulatory adjustments can lead to instability of the intracranial system in pathological conditions. In particular, analysis of the linearized system "in the small" demonstrates that an impairment in cerebrospinal fluid (CSF) reabsorption, a decrease in intracranial compliance and a high-regulatory capacity of the cerebrovascular bed are all conditions which can lead the system equilibrium to become unstable (i.e., the real part of at least one eigenvalue to turn out positive). Accordingly, mathematical simulation "in the large," in the above-mentioned conditions, exhibits intracranial pressure periodic fluctuations which closely resemble, in amplitude, duration, frequency and shape, the well-known Lundberg A-waves (or plateau waves).