|
|
Effect of acquisition site compression in multisite photoplethysmography
Hofrová, Lucie ; Kolář, Radim (referee) ; Janoušek, Oto (advisor)
The theoretical part of the thesis describes the pulse wave's origin, the principle of photoplethysmography, and the influence of vein compression on the morphology of the photoplethysmograph caused by external pressure during PPG signal measurement. Furthermore, the thesis contains the measurement and analysis of the PPG bilateral signal, which is used for the evaluation of whether there are differences between the PPG signal measured on the left or the right side of the human body. A dataset consisting of 10 volunteers was created for evaluation. The practical part contains the algorithm which analysis the PPG signal. Furthermore, normalization and statistical analysis is performed. The results show that external pressure has an effect on pulse wave width analysis and heart rate. When the pressure is high, the ability of pulse wave analysis is impaired.
|
|
|
Influence of postural change to the pulse wave velocity in the upper limb
Sakmárová, Klára ; Hrušková, Jana (referee) ; Svačinová, Jana (advisor)
This thesis is devoted to the topic of pulse wave velocity in the upper limb based on changes in body position. The work includes a literature search from the mentioned area, where it focuses mainly on the cardiovascular system, the pulse wave, its propagation in the human body, the clinical significance of the pulse wave and the factors that affect it. Pulse wave examination has now become an important part of the preclinical diagnosis of atherosclerosis or arterial stiffness. Examination of the pulse wave velocity as well as examination of the vascular system as part of early diagnosis is highly desirable for the stratification of cardiovascular diseases and subsequent mortality. In this work we will evaluate the speed of the pulse wave based on the time distance between the oscillation R on the ECG and the passage of the pulse wave under the pressure sensor located on the finger. In the MATLAB, a software solution of selected procedures for ECG measurement and blood pressure recording heart rate after heart rate is made. The measured values on a group of volunteers are statistically processed and subsequently discussed.
|
|
|
Validaton of multichannel bioimpedance of vessels using synchronized vascular ultrasonography
Hidegová, Simona ; Kolářová, Jana (referee) ; Mézl, Martin (advisor)
The inclusion of a new device in clinical practice requires an adequate validation. The original publication which introduced multichannel bioimpedance monitor MBM was focused on discribing its technical parameters and demonstration measurements. Further evaluation desires comparision with other standard measuring device. This thesis describes pulse wave measurement by MBM and by other medical devices used for establishing cardiovascular risk. It proposes the validation experiment with synchronized vascular ultrasonography as a reference method. The process of the experimental measurement, aquired data and following data analysis are described in detail. The outputs of the experiment are statistically evaluated. The MBM’s performance and design of the experiment are discussed.
|
|
| |
|
| |
|
|
Evaluation of pulse wave velocity in the human body
Mezuláníková, Radka ; Viščor,, Ivo (referee) ; Jurák, Pavel (advisor)
This Mater's thesis deals with the evaluation of pulse wave velocity using multi-channel whole-body impedance cardiography. Data were taken from the group of healthy volunteers whose impedance changes were measured during rest, respiratory maneuvers, tilt and stress exercise. The result of this measurement are values of peaks of pulse wave time shifts towards R-wave. The velocity values towards the thorax electrodes were recalculated on the basis of knowledge about the pulse wave time shifts and the distances from the heart to the scanned locations, which were measured using the arterial segment's lengths.
|
|
|
Bioimpedance signal processing
Valíčková, Vladimíra ; Vondra, Vlastimil (referee) ; Soukup, Ladislav (advisor)
Theoretical part of this Bachelor thesis deals with properties measurement and use of bioim-pedance signal for medical diagnostics. The practical part deals with detection of important points in derivate bioimpedance signal that may be further used in various medical applicati-ons. This work compares three detection methods. The best results were achieved by a de-tection with fixed interval there were excluded only 1,09 % values. Very similar results had detector dependent on constant bioimpedance. Here was excreted 1.18 % of detections. Algo-rithms that are dependent on length of RR interval perform worse. Furthermore, there is cal-culated the Pulse wave velocity in six parts of the human body in a horizontal and tilt patient position. In the tilt position were the pulse wave velocity about 38.59 % faster than in hori-zontal.
|
|
|
Properties of pulse wave velocity in human body during various excitations
Matejková, Magdaléna ; Halámek, Josef (referee) ; Vondra, Vlastimil (advisor)
The thesis is concerned with the analysis of measuring pulse wave velocity in human body with the aid of whole-body multichannel bioimpedance which was developed at ISI AS CR, v.v.i.. The evaluation of pulse wave velocity can provide us with important information about the state of vessel compliance which is one of the basic parameters informing on their physiological state. The examination of the state of vascular system is a very important part of early diagnostics because its pathological states are the main contributor to the rise of cardiovascular diseases and disease mortality. The thesis is concerned with the theoretical analysis together with the available methods of valuation of the state of vascular system that use measuring of pulse wave velocity. The main part of the thesis deals with the analysis of the whole-body multichannel bioimpedance measurement. The proposed and programmed protocol that summarizes and visualizes all obtained information is a part of this thesis. This is currently used as an output of the experimental measurement by this method. Data file for statistical processing contains the values of the pulse wave velocity of 35 healthy volunteers and subsequently the properties of pulse wave are assessed at various excitations.
|
|
|
Automatic determination of the pulse wave velocity in a body segment
Kampo, Dávid ; Svačinová, Jana (referee) ; Vondra, Vlastimil (advisor)
This Bachelor´s thesis deals with a propagation of a pulse wave velocity in different body segments and its measurement through bioimpedance. In connection with this topic, the work includes a profound description of a pulse wave and its velocity in regards to diagnostics and prevention of cardiovascular diseases that have been prevailing in recent years. During the process of determination of PWV, ECG is recorded, as it helps to accurately estimate the relevant transition times and the reulting PWV. The main purpose of this work is to validate that PWV can be determined without supportive ECG signals, what as a result makes the whole process simpler, more effective and available. The main target of this work has been successfully achieved and the algorithm for an evaluation of transition times and determination of PWV is described in the work. Moreover, the algorithm is implied to the structure of GUI in Matlab programm where the interface has been designed to suit the user´s needs to analyse PWV. Highlighting the validation process and functionality of the algorithm, signals from 21 subjects have been used to assess some of the most frequent analysed PWVs and all average values of velocities are within a physiological range from 5 m/s to 15 m/s. cfPWV is considered as a golden standard when it comes to PWV and the average value for all 21 subjects has been estimated to 7,54 m/s what corresponds with values from scientific studies that have been assessing cfPWV.
|
|
| |
guest ::
