Browsing by Author "Žikić, Dejan (55885785200)"

We performed continuous synchronized recordings of the blood flow in the brachial artery, electrocardiogram (ECG) and respiration, in different body positions, using a newly developed photoplethysmograph (PPG) sensor. Study of the arterial blood flow was done using a novel mathematical method developed for this purpose. The analyses of 5-minute recording sessions, at constant breathing frequency, showed a high correlation between the arterial blood flow and the heart rate. In addition, the analyses of blood flow recordings from the carotid artery revealed a significant correlation with the heart rate, despite the signal disturbance induced by neck muscle movement during the respiratory circle. Along with arterial blood flow, we performed recordings of peripheral blood flow using an identical PPG sensor. The analyses demonstrate that the arterial blood flow is in better correlation with the heart rate than the peripheral blood flow. © 2010 Taylor & Francis.

We performed continuous synchronized recordings of the blood flow in the brachial artery, electrocardiogram (ECG) and respiration, in different body positions, using a newly developed photoplethysmograph (PPG) sensor. Study of the arterial blood flow was done using a novel mathematical method developed for this purpose. The analyses of 5-minute recording sessions, at constant breathing frequency, showed a high correlation between the arterial blood flow and the heart rate. In addition, the analyses of blood flow recordings from the carotid artery revealed a significant correlation with the heart rate, despite the signal disturbance induced by neck muscle movement during the respiratory circle. Along with arterial blood flow, we performed recordings of peripheral blood flow using an identical PPG sensor. The analyses demonstrate that the arterial blood flow is in better correlation with the heart rate than the peripheral blood flow. © 2010 Taylor & Francis.

The velocity by which the disturbance travels through the medium is the wave velocity. Pulse wave velocity is one of the main parameters in hemodynamics. The study of wave propagation through the fluid-fill elastic tube is of great importance for the proper biophysical understanding of the nature of blood flow through of cardiovascular system. The effect of viscosity on the pulse wave velocity is generally ignored. In this paper we present the results of experimental measurements of pulse wave velocity (PWV) of compression and expansion waves in elastic tube. The solutions with different density and viscosity were used in the experiment. Biophysical model of the circulatory flow is designed to perform measurements. Experimental results show that the PWV of the expansion waves is higher than the compression waves during the same experimental conditions. It was found that the change in viscosity causes a change of PWV for both waves. We found a relationship between PWV, fluid density and viscosity. © 2015 Elsevier Ltd.

The velocity by which the disturbance travels through the medium is the wave velocity. Pulse wave velocity is one of the main parameters in hemodynamics. The study of wave propagation through the fluid-fill elastic tube is of great importance for the proper biophysical understanding of the nature of blood flow through of cardiovascular system. The effect of viscosity on the pulse wave velocity is generally ignored. In this paper we present the results of experimental measurements of pulse wave velocity (PWV) of compression and expansion waves in elastic tube. The solutions with different density and viscosity were used in the experiment. Biophysical model of the circulatory flow is designed to perform measurements. Experimental results show that the PWV of the expansion waves is higher than the compression waves during the same experimental conditions. It was found that the change in viscosity causes a change of PWV for both waves. We found a relationship between PWV, fluid density and viscosity. © 2015 Elsevier Ltd.

Introduction: Aging is a physiological process characterized by progressive changes in all organ systems. In the last few decades, the elderly population has been growing, so the scientific community is focusing on the investigation of the aging process, all in order to improve the quality of life in elderly. One of the biggest challenges in studying the impact of the aging on the human body represents the monitoring of the changes that inevitably occur in arterial blood vessels. Therefore, the medical community has invested a great deal of effort in studying and discovering new methods and tools that could be used to monitor the changes in arterial blood vessels caused by the aging process. The goal of our research was to develop a new diagnostic method using a photoplethysmographic sensor and to examine the impact of the aging process on the cardiovascular system in adults. Long-term recorded arterial blood flow waveforms were analyzed using detrended fluctuation analysis. Materials and Methods: The study included 117 respondents, aged 20–70 years. The waveform of the arterial blood flow was recorded for 5 min, with an optical sensor placed above the left common carotid artery, simultaneously with a single-channel ECG. For each cardiac cycle, the blood flow amplitude was determined, and a new time series was formed, which was analyzed non-linearly (DFA method). The values of the scalar coefficients α1 and α2, particularly their ratio (α1/α2) were obtained, which were then monitored in relation to the age of the subjects. Result: The values of the scalar ratio (α1/α2) were significantly different between the subjects older and younger than 50 years. The value of the α1/α2 decreased exponentially with the aging. In the population of middle-aged adults, this ratio had a value around 1, in young adults the value was exclusively higher than 1 and in older adults the value was exclusively lower than 1. Conclusion: The results of this study indicated that the aging led to a decrease in the α1/α2 in the population of healthy subjects. With this non-invasive method, changes in the cardiovascular system due to aging can be detected and monitored. Copyright © 2023 Djurić, Žikić, Nestorović, Lepojević-Stefanović, Milošević and Žikić.

Introduction: Aging is a physiological process characterized by progressive changes in all organ systems. In the last few decades, the elderly population has been growing, so the scientific community is focusing on the investigation of the aging process, all in order to improve the quality of life in elderly. One of the biggest challenges in studying the impact of the aging on the human body represents the monitoring of the changes that inevitably occur in arterial blood vessels. Therefore, the medical community has invested a great deal of effort in studying and discovering new methods and tools that could be used to monitor the changes in arterial blood vessels caused by the aging process. The goal of our research was to develop a new diagnostic method using a photoplethysmographic sensor and to examine the impact of the aging process on the cardiovascular system in adults. Long-term recorded arterial blood flow waveforms were analyzed using detrended fluctuation analysis. Materials and Methods: The study included 117 respondents, aged 20–70 years. The waveform of the arterial blood flow was recorded for 5 min, with an optical sensor placed above the left common carotid artery, simultaneously with a single-channel ECG. For each cardiac cycle, the blood flow amplitude was determined, and a new time series was formed, which was analyzed non-linearly (DFA method). The values of the scalar coefficients α1 and α2, particularly their ratio (α1/α2) were obtained, which were then monitored in relation to the age of the subjects. Result: The values of the scalar ratio (α1/α2) were significantly different between the subjects older and younger than 50 years. The value of the α1/α2 decreased exponentially with the aging. In the population of middle-aged adults, this ratio had a value around 1, in young adults the value was exclusively higher than 1 and in older adults the value was exclusively lower than 1. Conclusion: The results of this study indicated that the aging led to a decrease in the α1/α2 in the population of healthy subjects. With this non-invasive method, changes in the cardiovascular system due to aging can be detected and monitored. Copyright © 2023 Djurić, Žikić, Nestorović, Lepojević-Stefanović, Milošević and Žikić.