CARDIAC AND RESPIRATORY-RELATED ELECTRICAL-IMPEDANCE CHANGES IN THE HUMAN THORAX
CARDIAC AND RESPIRATORY-RELATED ELECTRICAL-IMPEDANCE CHANGES IN THE HUMAN THORAX
复制标题
DOI：
10.1109/10.310088
复制
发表时间：
1994-08-01
影响因子：
4.6
通讯作者：
LEATHARD, AD
中科院分区：
文献类型：
--
作者：
BROWN, BH;BARBER, DC;LEATHARD, AD
在9.6 kHz至614 kHz的频率范围内对人体躯干进行了电阻抗测量。测量已从12个正常受试者和与心脏和呼吸周期相关的阻抗变化的幅度已被记录。结果发现，阻抗的真实的部分在测量的频率范围内下降到其低频值的64.0%，并且与呼吸相关的变化以类似的方式下降。然而，心脏相关变化随频率增加而下降更快，达到低频值的28.2%。测量的变化的起源进行了讨论，以了解为什么心脏相关的变化下降得更快。不可能以任何简单的方式将单个分量的频散与整个干线的频散联系起来。然而，结果与肺是心脏和呼吸相关组分的主要来源一致。心脏相关阻抗变化的起源可能是肺动脉树中的脉动容积变化。这些可以被非脉动肺组织分流，非脉动肺组织在高频下具有降低的阻抗，从而降低心脏相关变化的相对幅度。这一假设需要进行测试，从胸部和3-D模型的躯干局部测量。
Electrical impedance measurements have been made from the human trunk over the frequency range 9.6 kHz to 614 kHz. Measurements have been made from 12 normal subjects and the amplitude of the impedance changes associated with the cardiac and respiratory cycles have been recorded. It was found that the real part of the impedance fell to 64.0% of its low frequency value over the measured range of frequencies and that the changes associated with respiration fell in a similar manner. However, the cardiac related changes fell more rapidly with increasing frequency to 28.2% of the low frequency value. The origin of the measured changes is discussed with a view to understanding why the cardiac related changes fall more rapidly. It is not possible to relate in any simple way the frequency dispersion of a single component to that of the whole trunk. However, the results are consistent with the lungs being the major origin of both the cardiac and respiratory related components. The origin of the cardiac related impedance changes could be the pulsatile volume changes in the pulmonary tree. These could be shunted by nonpulsatile lung tissue that has decreasing impedance at high frequency and thus decreases the relative magnitude of the cardiac related changes. This hypothesis needs to be tested using localized measurements from the thorax and 3-D modeling of the trunk.