Heart failure (HF) is a major clinical, social, and economic problem. In view of the important role of fluid overload in the pathogenesis of HF exacerbation, early detection of fluid retention is of key importance in preventing emergency admissions for this reason. However, tools for monitoring volume status that could be widely used in the home setting are still missing. The physical properties of human tissues allow for the use of impedance-based noninvasive methods, whose different modifications are studied in patients with HF for the assessment of body hydration. The aim of this paper is to present the current state of knowledge on the possible applications of these methods for remote (home-based) monitoring of patients with HF.
Accurate and reliable determination of the characteristic points of the impedance cardiogram (ICG) is an important research problem with a growing range of applications in the cardiological diagnostics of patients with heart failure (HF). The shapes of the characteristic waves of the ICG signal and the temporal location of the characteristic points B, C, and X provide significant diagnostic information. On this basis, essential diagnostic cardiological parameters can be determined, such as, e.g., cardiac output (CO) or stroke volume (SV). Although the importance of this problem is obvious, we face many challenges, including noisy signals and the big variability in the morphology, which altogether make the accurate identification of the characteristic points quite difficult. The paper presents an effective method of ICG points identification intended for conducting experimental research in the field of impedance cardiography. Its effectiveness is confirmed in clinical pilot studies.
The accurate detection of fiducial points in the impedance cardiography signal (ICG) has a decisive impact on the proper estimation of diagnostic parameters such as stroke volume or cardiac output. It is, therefore, necessary to find an algorithm that is able to assess their positions with great precision. The solution to this problem is, however, quite challenging with regard to the high sensitivity of the ICG technique to the noise and varying morphology of the acquired signals. The aim of this study is to propose a novel method that allows us to overcome these limitations. The developed algorithm is based on Empirical Mode Decomposition (EMD)—an effective technique for processing and analyzing various types of non-stationary signals. We find high correlations between the results obtained from the algorithm and annotated by an expert. This, in turn, implies that the difference in estimation of the diagnostic-relevant parameters is small, which suggests that the method can automatically provide precise clinical information.
This study presents a novel, non-invasive system designed to assess the fitness of flight personnel in extreme environments. Existing methods for evaluating pilot readiness lack objectivity, precision, and adaptability to dynamic flight conditions. Our system addresses these shortcomings by integrating mobile physiological measurement modules with an aircraft simulator, a Lower Body Negative Pressure (LBNP) system, and advanced analytical software. It continuously monitors critical physiological parameters, including heart rate, blood pressure, blood oxygen saturation, respiratory rate, and carotid blood flow, using innovative sensor placements that minimize motion artifacts. This approach offers a cost-effective and efficient alternative to traditional centrifuge-based assessments, which are costly and physically demanding. Preliminary tests demonstrate the system’s stability and ability to acquire consistent signals despite motion disturbances. Ongoing validation studies will compare the physiological data obtained in the LBNP simulator with centrifuge data, ensuring the system’s effectiveness in real-world aviation applications.