权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Estimation of the aortic flow and clinical application of thoracic bio-electrical impedance method.

胸部生物电阻抗法主动脉血流的估计及临床应用

基本信息

批准号：
63570408
负责人：
FUJINAMI Takao
金额：
$ 1.28万
依托单位：
Nagoya City University Medical School
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63570408/
关键词：
Bio-electric impedance method Aortic blood flow Water volume in tissue atherosclerosis obliterance Lung congestion Pulmonary edema Pulmonary extravascular water volume Frequency variation on bio-electrical impedance 生体電気インピーダンスインピーダンス・カ

项目摘要

When a constant high frequency alternative electric current is passed through the thorax, voltage change detected from the chest refers to the thoracic electrical property. Bioelectrical impedance is obtained as the ratio of voltage to alternative electrical current. From the thoracic impedance change, Kubicek has introduced impedance cardiography to estimate stroke volume non-invasively. Present studies are intended to expand clinical application of the thoracic bio-electrical impedance method to obtain more informations on the circulation. Following results were obtained.1) To eliminate impedance change by respiration, we have recorded the thoracic impedance change (DELTA Z) without holding respiration to a data recorder, then DELTA Z data was digitalized by A-D converter, and respiratory fluctuation of DELTA Z was obtained by cubic spline interpolation. By subtraction of respiratory DELTA Z change from original DELTA Z, new DELTA Z wave without respiration change was obtained.2) To … More detect aortic flow selectively by bio-electrical impedance changes, the electrodes were positioned at the point of V_8 of ECG and of second thoracic vertebra on the posterior median line. By this lead system, height of the first derivative of impedance change (dZ/dt) wave was correlated with the aortic flow velocity obtained by the catheter tip velocity transducer (r= 0.84). This result indicates that the impedance change of this system reflects aortic flow. An index of the aortic compliance was calculated from division of amplitude of the impedance change (DELTA Z) by pulse pressure. This index(Y) was correated with volume elasticity(X) obtained, from RI angiography by equation of Y = 124.52 X100/X + 4.52 (r = 0.78, P<0.001).3) Ratio of aortic flow and lower leg determined with bioelectric impedance method was valuable for diagnosis of arteriosclerosis obliterance (ASO).4) Using frequency variable impedance analyzer, tissue fluid changes in the leg during pregnancy were studied. Lower frequency of applied current may pass through extra-cellular fluid, and high frequency of the current may pass both extra- and intra- cellular fluid. We used 12 steps of frequency from 2 kHz to 300 kHz for the study and estimated resistance of extracellular fluid (Re) and of intra cellular fluid (Ri) from a locus of admittance. An apparent increase in Re during the mid term of pregnancy was observed.5) Determination of water content in the thorax to estimate degree of lung congestion (congestive heart failure) was intended. The thorax was considered as truncated cone model and mean thoracic impedance (rho chest) was calculated from basal thoracic impedance (Zo) of Kubicek's impedance cardiography with variable frequency from 2 kHz to 200 kHz. The highest rho chest value was obtained at the frequency of 10 KHz. and significantly low rho chest value in the patients with pulmonary edema as compared with the healthy control subjects.Although, it is considered that the applied electric current does not distribute equally through the lung, we used an experimental model with one of the electrode in the central vein and the other on the surface of the thorax. Experimental model of congestive heart failure was induced in rabbits by infusion of 70% dextran solution and bio-electrical impedance was determined between an electrode in the central vein and combined electrode at the neck and lower thoracic. Pulmonary extravascular water volume was determined by the method of Pearce and Yamashita on desiccated lung at the end of the experiment. Impedance at 10 kHz of applied electric current was significantly correlated with PEWV (r= 0.87) and central venous pressure (r=0.93) Application for human study is under consideration. Less

当恒定的高频交流电流通过胸腔时，从胸腔检测到的电压变化是指胸腔电特性。生物电阻抗是以电压与交流电流的比率获得的。从胸阻抗变化，Kubicek引入了阻抗心动图来无创估计每搏输出量。本研究旨在扩大胸壁生物电阻抗法的临床应用，以获得更多的循环信息。结果表明：1）为了消除呼吸引起的阻抗变化，我们将不保持呼吸的胸阻抗变化（Δ Z）记录在数据记录仪上，然后将Δ Z数据经A-D转换器数字化，用三次样条插值法得到Δ Z的呼吸波动。通过从原始DELTA Z减去呼吸DELTA Z变化，获得没有呼吸变化的新DELTA Z波。 ...更多信息通过生物电阻抗变化选择性检测主动脉血流，电极定位于心电图V_8点和第二胸椎后正中线上。通过该电极系统，阻抗变化的一阶导数（dZ/dt）波的高度与由导管尖端速度传感器获得的主动脉流速相关（r= 0.84）。该结果表明，该系统的阻抗变化反映了主动脉血流。主动脉顺应性的指数由阻抗变化的幅度（Δ Z）除以脉压来计算。该指数（Y）与RI血管造影测量的容积弹性（X）之间的相关方程为Y = 124.52 × 100/X + 4.52（3）生物电阻抗法测定主动脉血流与下肢血流比值对动脉硬化闭塞症（阿索）的诊断有一定价值。研究了妊娠期间腿部组织液的变化。较低频率的施加电流可以通过细胞外流体，并且高频率的电流可以通过细胞外流体和细胞内流体两者。我们使用了12个步骤的频率从2 kHz到300 kHz的研究和估计电阻的细胞外液（Re）和细胞内液（Ri）从一个轨迹的导纳。在妊娠中期，Re明显增加。5）测定胸腔含水量以估计肺充血（充血性心力衰竭）的程度。胸部被认为是截锥模型，平均胸阻抗（rho胸部）由Kubicek阻抗心动图的基础胸阻抗（Zo）计算，频率从2 kHz到200 kHz。在10 KHz频率下获得最高的rho胸部值。肺水肿患者的Rho胸值显著低于健康对照者。虽然认为施加的电流在肺中分布不均匀，但我们使用了一个电极位于中心静脉而另一个电极位于胸部表面的实验模型。用70%右旋糖酐溶液建立家兔充血性心力衰竭模型，测定中心静脉电极与颈胸联合电极间的生物电阻抗。实验结束时，用皮尔斯和山下法测定干燥肺血管外水含量。施加电流10 kHz时的阻抗与PEWV（r= 0.87）和中心静脉压（r=0.93）显著相关。正在考虑用于人体研究。少