Research And System Development Of Noninvasive Heart Output Detection

Cardio-cerebrovascular disease is a serious threat to human health. According to statistics every year millions of people die from cardio-cerebrovascular disease, and its morbidity and mortality is still rising. As an important indicator of assessing cardiovascular function, the detection of stroke volume(Stroke volume, SV), cardiac output(Cardiac output, CO) and other hemodynamic parameters has an important significance. At present, thermodilution is the "gold standard" for the clinical detection of cardiac output, but this method is invasive detection and easy to cause other complications, which makes the method difficult to be widely used in clinical applications. In recent years, the thoracic impedance method as the method for noninvasive detection of cardiac output, its accuracy and reliability has been widely recognized in clinical medicine, related detecting equipment has been used in clinical.This study first analyzes in detail the principle of the thoracic impedance method. The thoracic impedance method realizes the noninvasive detection of cardiac output estimation based on the thorax cylinder model of Nyboer and the formula for estimating stroke volume(SV) of Kubieck. Based on the principle of the thoracic impedance method, this study developed the thoracic impedance detection system, which is used to obtain the distribution of the thoracic impedance and impedance cardiogram.This paper also illustrates the determination of generation scheme of constant current sine signal, the design of ECG detection circuit and the design of electrical impedance detection circuit. In this design, Matlab software is used to process data, which can make the test results more intuitive.Through a lot of experiments in this paper, the location of using the spot electrode instead of strip electrode for cardiac output measurement is discussed, and by getting the impedance cardiogram on detection electrodes of the center of the chest line the human cardiac output noninvasive and unrestrained detection is completed.