Deterministic Chaos in the Hemodynamics of an Artificial Heart
Deterministic Chaos in the Hemodynamics of an Artificial Heart
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人工心脏血流动力学中的确定性混沌
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
M. Yoshizawa
中科院分区：
文献类型：
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作者：
T. Yambe;S. Nitta;T. Sonobe;Y. Kakinuma;K. Izutsu;H. Akiho;S. Kobayashi;N. Ohsawa;T. Fukuju;M. Miura;N. Uchida;N. Sato;K. Tabayashi;S. Koide;K. Abe;H. Takeda;M. Yoshizawa
为了将人工循环期间的血流动力学参数作为一个整体进行分析，使用了非线性数学技术。为了比较自然循环和人工循环，在成年山羊的慢性动物实验中植入两种双心室驱动的心室辅助装置作为双心室旁路，以建立心室颤动的双心室旁路完全人工循环模型。植入后，将这些山羊置于笼中，清醒后拔管。在清醒状态下记录自然循环无双心室转流泵送和心室颤动情况下人工循环有双心室转流泵送的所有血流动力学参数。利用非线性数学技术，将动脉血压波形嵌入到四维相空间中，并投影到三维相空间中。李雅普诺夫数值方法被用来作为一个辅助的图形分析的状态空间。吸引子的相图显示了一个高维的复杂结构，三维固体环面表明在自然循环过程中的确定性混沌。然而，一个简单的吸引子，如极限环吸引子，在人工循环过程中观察到。人工循环过程中的正李雅普诺夫指数表明系统是低维混沌系统。因此，在人工循环过程中的血液动力学参数必须仔细控制时，意外的刺激，从外部馈送。
To analyze the hemodynamic parameters during prosthetic circulation as an entity, non linear mathematical techniques were used. To compare natural and prosthetic circulation, two pneumatically actuated ventricular assist devices were implanted as biventricular bypasses in chronic animal experiments using adult goats to consitute the biventricular bypass complete prosthetic circulation model with ventricular fibrillation. After implantation, these goats were placed in a cage and extubated after waking. All hemodynamic parameters with the natural circulation without biventricular bypass pumping, and the artificial circulation with biventricular bypass pumping under ventricular fibrillation were recorded under awake conditions. By the use of a non linear mathematical technique, the arterial blood pressure waveform was embedded into a four dimensional phase space and projected into three dimensional phase space. The Lyapunov numeric method is used as an adjunct to the graphic analysis of the state space. A phase portrait of the attractor showed a high dimension complex structure, with three dimensional solid torus suggesting deterministic chaos during natural circulation. However, a simple attractor, such as a limit cycle attractor, was observed during artificial circulation. Positive Lyapunov exponents during artificial circulation suggest the lower dimensional chaotic system. Thus, hemodynamic parameters during prosthetic circulation must be carefully controlled when unexpected stimuli are fed from outside.