Multifractal Analysis of Hemodynamic Behavior: Intraoperative Instability and Its Pharmacological Manipulation
Multifractal Analysis of Hemodynamic Behavior: Intraoperative Instability and Its Pharmacological Manipulation
复制标题
血流动力学行为的多重分形分析：术中不稳定性及其药理操作
作者：
S. Bishop;S. Yarham;V. Navapurkar;D. Menon;A. Ercole
背景：生理性不稳定是危重病患者常见的临床问题。许多自然反馈系统是非线性的，看似随机的波动可能是外部扰动放大的结果，甚至是潜在动力学的结果而从头开始。对潜在的非线性状态的表征可能具有临床重要性，提供了一种实时监测复杂生理、指导患者护理和改善结果的技术。方法：采用小波模极大值技术，对4例腹主动脉瘤修补术患者的心率和平均动脉压生理过程中的多重分形特征进行了回顾性研究。我们计算了心率和平均动脉压信号的主要Hölder指数(hmHR，hmMAP)和多重分形谱半高宽度的点估计。我们研究了静脉注射血管紧张剂后这些参数的变化，并研究了阿托品预处理对这些参数的影响。结果：低血压患者的hmMAP值较低，与波动较大和复杂的行为相一致。血管紧张剂治疗导致hmMAP的一过性升高，显示出较长范围的相关性，但不影响hmHR。另一方面，阿托品预先治疗对hmMAP行为没有影响，但有增加hmHR的趋势。结论：低血压导致平均动脉压的优势Hölder指数降低，显示出与重要的顺势过程的激活一致的信号复杂性的增加。相反，药物干预也可能改变潜在的动态。动态平衡的药理学恢复导致系统解链，这表明动态平衡机制随着动态平衡的恢复而被破坏。
Background:Physiologic instability is a common clinical problem in the critically ill. Many natural feedback systems are nonlinear, and seemingly random fluctuations may result from the amplification of external perturbations or even arise de novo as a consequence of their underlying dynamics. Characterization of the underlying nonlinear state may be of clinical importance, providing a technique to monitor complex physiology in real-time, guiding patient care and improving outcomes. Methods:We employ the wavelet modulus maxima technique to characterize the multifractal properties of heart rate and mean arterial pressure physiology retrospectively for four patients during open abdominal aortic aneurysm repair. We calculated point-estimates for the dominant Hölder exponent (hmHR, hmMAP) and multifractal spectrum width-at-half-height for both heart rate and mean arterial pressure signals. We investigated how these parameters changed with the administration of an intravenous vasoconstrictor and examined how this varied with atropine pretreatment. Results:Hypotensive patients showed lower values of hmMAP, consistent with a more highly fluctuating and complex behavior. Treatment with a vasoconstrictor led to a transient increase in hmMAP, revealing the appearance of longer-range correlations, but did not impact hmHR. On the other hand, prior treatment with atropine had no effect on hmMAP behavior but did tend to increase hmHR. Conclusions:Hypotension leads to a reduction in dominant Hölder exponents for mean arterial pressure, demonstrating an increasing signal complexity consistent with the activation of important homeokinetic processes. Conversely, pharmacological interventions may also alter the underlying dynamics. Pharmacological restoration of homeostasis leads to system decomplexification, suggesting that homeokinetic mechanisms are derecruited as homeostasis is restored.
影响因子：
3.3
作者：
HAUSDORFF, JM;PENG, CK;GOLDBERGER, AL
通讯作者：
GOLDBERGER, AL