Contribution of mathematical modelling to the interpretation of bedside tests of cerebrovascular autoregulation
Contribution of mathematical modelling to the interpretation of bedside tests of cerebrovascular autoregulation
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DOI：
10.1136/jnnp.63.6.721
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发表时间：
1997-12-01
影响因子：
11
通讯作者：
Pickard, JD
中科院分区：
文献类型：
--
作者：
Czosnyka, M;Piechnik, S;Pickard, JD
目的：脑血流动力学对短期和长期脑灌流压降低事件的反应包含有关脑血流自动调节状态的信息。数学模拟可以帮助阐明哪些指标可以通过经颅多普勒超声获得，以及颅内压和血压的变化趋势，用于自我调节储备的临床测试。方法使用一组非线性微分方程来模拟脑血流和脑脊液的压力、流量和容量之间的时间依赖的相互作用。该模型模拟了动脉血流入和储存、脑自动调节控制的微动脉和毛细血管血流量、颅内压变化调节的静脉血储存和静脉流出以及脑脊液储存和重吸收的变化。该模型被用来模拟大脑灌流压在短期或长期下降期间的血流模式。这些模拟可以被认为在临床上等同于颈总动脉短时间压迫、全身性低血压和颅内高压。在自动调节和非自动调节系统中进行模拟，并与患者获得的记录进行比较。结果-在短暂压迫颈总动脉后，随后的一过性充血可被解释为完整的自我调节的证据。在持续的持续低灌流过程中，血流速度波形的收缩期值逐渐增加，舒张期值逐渐降低，这是脑血管系统自我调节的特有现象。结论模型研究有助于解释临床和实验脑血流动力学现象及其对自我调节状态的依赖。
Objectives-Cerebral haemodynamic responses to short and longlasting episodes of decreased cerebral perfusion pressure contain information about the state of autoregulation of cerebral blood flow. Mathematical simulation may help to elucidate which of the indices, that can be derived using transcranial Doppler ultrasonography and trends of intracranial pressure and blood pressure, are useful in clinical tests of autoregulatory reserve.Methods-Time dependent interactions between pressure, flow, and volume of cerebral blood and CSF were modelled using a set of non-linear differential equations. The model simulates changes in arterial blood inflow and storage, arteriolar and capillary blood flow controlled by cerebral autoregulation, venous blood storage and venous outflow modulated by changes in ICP, and CSF storage and reabsorption. The model was used to simulate patterns of blood flow during either short or longlasting decreases in cerebral perfusion pressure. These simulations can be considered as clinically equivalent to a short compression of the common carotid artery, systemic hypotension, and inh acranial hypertension. Simulations were performed in autoregulating and non-autoregulating systems and compared with recordings obtained in patients.Results-After brief compression of the common carotid artery, a subsequent transient hyperaemia can be interpreted as evidence of intact autoregulation. During longlasting sustained hypoperfusion, a gradual increase in the systolic value of the blood flow velocity waveform along with a decrease in the diastolic value is specific for an autoregulating cerebrovascular system.Conclusion-Modelling studies help to interpret both clinical and experimental cerebral haemodynamic phenomena and their dependence on the state of autoregulation.