Design and development of a novel Invasive Blood Pressure simulator for patient's monitor testing

This paper presents a newly-designed and realized Invasive Blood Pressure (IBP) device for the simulation on patient’s monitors. This device shows improvements and presents extended features with respect to a first prototype presented by the authors and similar systems available in the state-of-the-art. A peculiarity of the presented device is that all implemented features can be customized from the developer and from the point of view of the end user. The realized device has been tested, and its performances in terms of accuracy and of the back-loop measurement of the output for the blood pressure regulation utilization have been described. In particular, an accuracy of ±1 mmHg at 25 °C, on a range from −30 to 300 mmHg, was evaluated under different test conditions. The designed device is an ideal tool for testing IBP modules, for zero setting, and for calibrations. The implemented extended features, like the generation of custom waveforms and the Universal Serial Bus (USB) connectivity, allow use of this device in a wide range of applications, from research to equipment maintenance in clinical environments to educational purposes. Moreover, the presented device represents an innovation, both in terms of technology and methodologies: It allows quick and efficient tests to verify the proper functioning of IBP module of patients’ monitors. With this innovative device, tests can be performed directly in the field and faster procedures can be implemented by the clinical maintenance personnel. This device is an open source project and all materials, hardware, and software are fully available for interested developers or researchers.Web of Science201art. no. 25

A wavelet-based VCG QRS loop boundaries and isoelectric coordinates detector

This paper deals with a wavelet-based algorithm for automatic detection of isoelectric coordinates of individual QRS loops of VCG record. Fiducial time instants of QRS peak, QRS onset, QRS end, and isoelectric PQ interval are evaluated on three VCG leads (X, Y, Z) together with global QRS boundaries of a record to spatiotemporal QRS loops alignment. The algorithm was developed and optimized on 161 VCG records of PTB diagnostic database of healthy control subjects (HC), patients with myocardial infarction (MI) and patients with bundle branch block (BBB) and validated on CSE multilead measurement database of 124 records of the same diagnostic groups. The QRS peak was evaluated correctly for all of 1,467 beats. QRS onset, QRS end were detected with standard deviation of 5,5 ms and 7,8 ms respectively from the referee annotation. The isoelectric 20 ms length PQ interval window was detected correctly between the P end and QRS onset for all the cases. The proposed algorithm complies the (2 sigma(CSE)) limits for the QRS onset and QRS end detection and provides comparable or better results to other well-known algorithms. The algorithm evaluates well a wide QRS based on automated wavelet scale switching. The designed multi-lead approach QRS loop detector accomplishes diagnostic VCG processing, aligned QRS loops imaging and it is suitable for beat-to-beat variability assessment and further automatic VCG classification.Web of Science13art. no. 94182

Simulátor snímače invazivního tlaku

Import 19/06/2007Prezenční455 - Katedra měřicí a řídicí technik

Visualisation of one chip microcontroler for data visualisation

Diplomová práce se zabývá návrhem a realizací uživatelského komunikačního rozhraní pro příjem dat vitálních funkcí a jejich vizualizací. Řídící jednotkou je mikrokontrolér AVR ATmega644P. Data jsou zobrazována pomocí barevného STN displeje s řadičem PCF8833. Pomocí uživatelské nabídky na LCD a využitím několika tlačítek maticové klávesnice Nokie 6610 je vytvořeno uživatelské komunikační rozhraní. Uživatel má možnost zobrazit záznam aktuálního měření EKG a pletysmografie. Hodnoty jednorázových nebo časově podmíněných měření tlaku, hmotnosti, teploty, SpO2 a ID místnosti jsou ukládány pro pozdější vyhodnocení a prohlížení ve vytvořeném nástroji trendových grafů. Na LCD lze dále zobrazit aktuální pozici sledované osoby v monitorovaném prostoru. V externí paměti FLASH, připojené k μC jsou uložena obrazová data uživatelské nabídky, naměřené hodnoty, mapa monitorovaného prostoru a nastavení. Paměť je programovatelná z uživatelského rozhraní prostřednictvím sběrnice USART. Komunikace mezi μC, řadičem LCD a externí pamětí FLASH probíhá prostřednictvím SPI. Příjem dat je realizován prostřednictvím TWI (I2C). Diplomová práce je součástí projektu CERBERUS II.This diploma thesis deals with design and realisation of communication interface for vital function data receiving and visualisation. The control unit for the communication interface is AVR ATmega644P. The data are displayed by color STN LCD with integrated PCF8833 controller and driver. The user communication interface is realised by user menu displayed on LCD and by keyboard buttons of the Nokia 6610 matrix keyboard. User can display actual measuring of EKG and pletysmograph curves. Values of temporal measured pressure, weight, temperature, SpO2 and room ID are stored in memory for later browsing and evaluation using the trend graph tool. It is possible to display the position of monitored person in defined territory. In the external data FLASH memory, connected to the μC, are stored the image data, user interface icons, measured values, data image of monitored area, settings. The FLASH memory is programmable by user interface through the USART. Communication between μC, LCD driver and external FLASH is realised by SPI. Data receiving is realised by TWI (I2C). The diploma thesis is a part of the CERBERUS II project.Prezenční455 - Katedra měřicí a řídicí technikyvýborn

An Octant Vectorcardiography-Based Automatic Classification of Ischemic Heart Diseases

Nedostatečné prokrvení srdce – ischemická choroba srdeční (IHD) je jednou z nejčastějších příčin světové úmrtnosti. Z tohoto důvodu se tato disertační práce zabývá problematikou vektorkardiografie (VKG) jako další elektrokardiografické diagnostiké metody a jejím využitím pro automatickou diagnostiku IHD. VKG přináší možnost neinvazivního, dostupného a levného vyšetření, které umožňuje rozpoznat správnou funkci srdce, upozornit na varovné signály, vyhodnotit stav ischemické choroby srdeční při běžném klinickém vyšetření a podat upřesňující informace vedle běžně používané metody 12svodového EKG. VKG popisuje elektrický prostor srdeční (EPS) kvantitativně souborem vlastností, které jsou vhodné pro další zpracování a automatické vyhodnocování IHD za použití výpočetní techniky a klasifikačních algoritmů. Hlavním cílem této disertační práce je návrh algoritmu pro automatickou klasifikaci pacientů s IHD na základě záznamů VKG s využitím metod široce zpracované teorie Laufbergerovy oktantové VKG pro kvantitativní popis EPS a s využitím kybernetických přístupů pro zpracování signálů metodou digitální filtrace (FIR), waveletové transformace (WT), statistické analýzy pro výběr významných vlastností EPS a klasifikačních metod loglineárního modelování (LR) a umělé inteligence (MLP). Navržený algoritmus umožňuje rozpoznávat pacienty s diagnózami HC, MI-I, MI-A a BBB: se senzitivitou 78 % a specificitou 83 % pro klasifikaci HC; senzitivitou 58 % a specificitou 90 % pro klasifikaci MI-I; senzitivitou 63 % a specificitou 90 % pro klasifikaci MI-A a senzitivitou 92 % a specificitou 88 % pro klasifikaci BBB. Rozšířením vstupní databáze pro návrh algoritmu o další záznamy a další diagnostické třídy s ověřenou fyziologií případů je možné dále rozšířit klasifikační schopnosti navrženého algoritmu o rozpoznání akutních i stabilních forem IHD s upřesněním stavu myokardu, rozsahu a lokalizace MI. Optimalizace algoritmu je možná na všech stupních klasifikačního procesu dále diskutované metodiky od měření, předzpracování dat, výběru vlastností a významných vlasností EPS až po metody klasifikace a to za účelem upřesnění elektrokardiografické diagnostiky. [Autorský abstrakt].Insufficient blood supply to the heart – ischemic heart disease (IHD) is the leading cause of mortality in the world. That is why this thesis deals with vectrocardiography (VCG) as the electrocardiographic diagnostic and its use for the automatic diagnosis of IHD. VCG has opportunity to non-invasive and inexpensive examination, that can recognize proper function of the heart, detect warning signs, evaluate condition of ischemic heart disease in common clinical examination and bring specific information in addition to commonly used 12lead ECG method. VCG describes an electric heart space (EHS) quantitatively by set of features that are suitable for further processing and automatic evaluation of IHD using computer technology and classification algorithms. The main aim of this thesis is to design an algorithm for automatic classification of patients with IHD based on VCG records using method of widely studied Laufberge‘s octant theory for quantitative description of EHS and using cybernetic approaches for signal processing using digital filtration (FIR), wavelet transformation (WT), statistical analysis for the importatnt features of the EHS selection and classification methods of loglinear modeling (LR) and artificial neural networks (MLP). The proposed algorithm allows to recognize patients with HC, MI-I, MI-A and BBB diagnoses with sensitivity of 78 % and specificity of 83 % for classification of HC, sensitivity of 58 % and specificity of 90 % for classification of MI-I, sensitivity of 63% and specificity of 90 % for classification of MI-A and sensitivity of 92 % and specificity of 88 % for classification of BBB. Additional classification performance can be achieved by extending the input database for the algorithm by additional records with physiology aproved by more accurate diagnostic methods for ability to recognize acute and stable forms of IHD with specific localisation. Proposed algorithm can be optimized at all levels of the classification process further discussed in the methodology, which includes measurement, data preprocessing, EHS features selection and important features selection and classification for the purpose of clarification of the electrocardiographic diagnosis. [Author's abstract].450 - Katedra kybernetiky a biomedicínského inženýrstvívyhově

Electronic invasive blood pressure simulator device for patient monitor testing

This work deal with design and realization of invasive blood pressure patient‘s side bad monitor testing by our original electronic device. Designed device enable to generate precise and wide range of pressure- voltage curve signal for using on any IBP monitors. User adaptive interface with display and control buttons makes it easy for use. The primary applications of these invasive blood pressure simulations are calibrating the patient’s monitors that are the general usages of the developed device. Ill. 9, bibl. 5, tabl. 3 (in English; abstracts in English and Lithuanian).Web of Science1196544

Present results and methods of vectorcardiographic diagnostics of ischemic heart disease

: This article presents an overview of existing approaches to perform vectorcardiographic (VCG) diagnostics of ischemic heart disease (IHD). Individual methodologies are divided into categories to create a comprehensive and clear overview of electrical cardiac activity measurement, signal pre-processing, features extraction and classification procedures. An emphasis is placed on methods describing the electrical heart space (EHS) by several features extraction techniques based on spatiotemporal characteristics or signal modelling and signal transformations. Performance of individual methodologies are compared depending on classification of extent of ischemia, acute forms - myocardial infarction (MI) and myocardial scars localization. Based on a comparison of imaging methods, the advantages of VCG over the standard 12-leads ECG such as providing a 3D orthogonal leads imaging, better performance, and appropriate computer processing are highlighted. The issues of electrical cardiac activity measurements on body surface, the lack of VKG databases supported by a more accurate imaging method, possibility of comparison with the physiology of individual cases are outlined as potential reserves for future research

Capacitive biopotential electrode with a ceramic dielectric layer

This paper presents the design of an innovative active capacitive electrode with a ceramic dielectric layer. The electrode meets the requirements for contactless measurement, resistance to motion artefacts and possibility to make long and repeated recordings. The proposed capacitive electrode is distinguished from other capacitive electrodes by the construction of the capacitive coupling element, which is placed on the body surface. While common capacitive electrodes use a metal plate with a relatively large surface area as the capacitive coupling element, the proposed electrode uses a dielectric ceramic layer with high permittivity and a surface area no greater than a few cm(2). In order to test the electrode, an electrocardiography (ECG) measuring system was designed. Several different dielectric materials, different sizes of the electrode surface, as well as different electronics of the electrode were compared. The results show 26 dB signal to noise ratio (SNR) for the electrode with a ceramic dielectric layer, which was put on a skin over a cotton fabric, compared to 13 dB SNR for an electrode with a metal plate with a four times larger surface area.Web of Science24599598