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

库比切克介绍，当恒定的高频交流电流通过胸部时，从胸部检测到的电压变化是指胸部电特性，即电压与交流电流的比值。目前的研究旨在扩大胸部生物电阻抗法的临床应用，以获得更多有关循环的信息。 1）为了消除呼吸引起的阻抗变化，我们在不进行呼吸的情况下将胸廓阻抗变化（DELTA Z）记录到数据记录仪中，然后通过A-D转换器将DELTA Z数据数字化，并通过三次方得到DELTA Z的呼吸波动通过样条插值从原始 DELTA Z 中减去呼吸 DELTA Z 变化，获得没有呼吸变化的新 DELTA Z 波。2) 选择性检测主动脉血流通过生物电阻抗变化，将电极定位在心电图的V_8点和后正中线上的第二胸椎点通过该导联系统，将阻抗变化（dZ/dt）波的一阶导数的高度相关联。与导管尖端速度传感器获得的主动脉血流速度（r=0.84）这一结果表明，该系统的阻抗变化反映了主动脉顺应性的一个指标。是用阻抗计算变化 (DELTA Z) 的幅度除以脉压得出的。该指数 (Y) 与从 RI 血管造影中通过方程 Y = 124.52 X100/X + 4.52 (r = 4.52) 获得的体积弹性 (X) 相关。 0.78, P<0.001).3) 生物电阻抗法测定主动脉血流与小腿血流之比对诊断动脉硬化闭塞症（ASO）。4）使用频率可变阻抗分析仪，研究了怀孕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液，而高频电流可以通过细胞外液和细胞外液。我们使用从 2 kHz 到 300 kHz 的 12 步频率进行研究，并从导纳点估计细胞外液 (Re) 和细胞内液 (Ri) 的阻力。观察到妊娠中期Re的增加。5)测定胸部的含水量以估计肺充血(充血性心力衰竭)的程度。胸部被认为是截锥体模型和平均胸部阻抗(rho胸部)。 ) 是根据 Kubicek 的阻抗心动图计算的胸部阻抗 (Zo) 计算的基础值，频率范围为 2 kHz 至 200 kHz 最高 rho。与健康对照受试者相比，在 10 KHz 频率下获得胸值，并且肺水肿患者的 rho 胸值明显较低。尽管我们认为所施加的电流在肺部分布不均。采用一电极在中央静脉，一电极在胸腔表面的实验模型，通过输注70%右旋糖酐溶液诱导家兔充血性心力衰竭实验模型，并测量生物电阻抗。实验结束时，通过 Pearce 和 Yamashita 的方法在干燥的肺上测定中央静脉的电极和颈部和下胸部的组合电极之间的阻抗。与 PEWV（r=0.87）和中心静脉压（r=0.93）显着相关。正在考虑应用于人体研究。