Newman D G, Callister R
Royal Australian Air Force Institute of Aviation Medicine, RAAF Base Edinburgh.
Aviat Space Environ Med. 1999 Aug;70(8):780-9.
Impedance cardiography (IC) is an inexpensive, reliable and noninvasive technique for determining stroke volume (SV) and cardiac output (CO). It relies on the measurement of phasic changes in transthoracic electrical resistivity, related to ejection of blood into the ascending aorta with each heart beat. Because of its non-invasive nature, IC is becoming increasingly used in clinical settings, as well as in many areas of physiological research. This paper discusses IC in terms of its theoretical basis, the components of the impedance signal and how impedance data is mathematically processed. One of the major controversies surrounding IC concerns how well it compares with conventional methods of determining SV and CO, such as thermodilution. A literature review of such comparative studies demonstrated that the controversy is far from settled, but that IC is generally agreed to be capable of accurately monitoring trends in cardiovascular dynamics. The question of accuracy of IC in terms of absolute values of SV and CO remains to be determined. The methodological limitations, accuracy, reliability and reproducibility of IC are examined, as are some of the methods developed to improve these aspects of the technique. The application and utility of IC in aerospace medicine research is also addressed.
阻抗心动图（IC）是一种用于测定每搏输出量（SV）和心输出量（CO）的廉价、可靠且无创的技术。它依赖于对经胸电阻抗相位变化的测量，这种变化与每次心跳时血液射入升主动脉有关。由于其无创性，IC在临床环境以及许多生理学研究领域中越来越多地得到应用。本文从其理论基础、阻抗信号的组成部分以及阻抗数据的数学处理方式等方面对IC进行了讨论。围绕IC的主要争议之一是它与测定SV和CO的传统方法（如热稀释法）相比的效果如何。对这类比较研究的文献综述表明，争议远未解决，但普遍认为IC能够准确监测心血管动力学趋势。IC在SV和CO绝对值方面的准确性问题仍有待确定。本文探讨了IC的方法学局限性、准确性、可靠性和可重复性，以及为改进该技术这些方面而开发的一些方法。还讨论了IC在航空航天医学研究中的应用和效用。
