Impedance rheography for systemic and pulmonary circulation study and clinical application

Abstract

A modified Kubicek's impedance cardiographic method for study of total systemic blood flow (SBF) and another own impedance method for investigation of right pulmonary artery blood flow (RPABF) and clinical applications of both methods was presented. The impedance measurements are based on tetrapolar current technique. The alternating current with amplitude of 1 mA and frequency about 100 kHz is used. The study methods are based on the analysis of anatomy of great cardiac arteries (aorta and pulmonary arteries) and simplified equivalent electrical circuits of the thorax and Kubicek's formula. The SBF investigations were carried out on 20 healthy persons and first group of 16 patients (pts) with systemic circulation disturbances (aortic stenosis or atherosis). The RPABF study was done on 20 healthy and the second group of 26 pts with pulmonary artery stenosis (separated stenosis or in Fallot Syndrome). The SBF and RPABF calculated per square meter of body surface (SBFi and RPABFi) appeared to be very important parameters for assessment of systemic and pulmonary circulation. The shape of impedance signals gives useful diagnostic information. For controls RPABFi = 3,34 ± 1,20 l/min/m2 and for first group of patients SBFi = 2,32 ± 1,10l/min/m2. For controls RPABFi = 1,94 ± 0,72 l/min/m2 and for second group of patients RPABFi = 1,16 ± 0,42 l/min/m2. Also the shape of proper impedance curves differs for healthy and patients. The presented methods are relatively non expensive, non invasive and helpful for diagnosis of systemic and/or pulmonary blood circulation abnormalities. © Springer-Verlag 2007.