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1
Content available Digital image correlation of coated and uncoated Religa Heart_Ext ventricular assist device
Kopernik M., Gawlikowski M., Milenin A., Altyntsev I., Kustosz R., Kąc S.
Acta of Bioengineering and Biomechanics
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2015
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Vol. 17, no. 4
49--58
EN
The digital image correlation is used to estimate influence of deposited heamocompatible coatings (gold and titanium nitride) on mechanical response of ventricular assist device Religa Heart_Ext made of Bionate II (thermoplastic polycarbonate urethane) under working conditions by comparison of the coated Religa Heart_Ext with uncoated Religa Heart_Ext. The DIC is applied for experimental investigation of the strains and displacements distribution on external surface of the blood chamber of ventricular assist device during loading. The experiment was conducted in a hydraulic system with water at operating temperatures of 25 and 37 °C, as well as under static pressures: 80, 120, 180, 220 and 280 mmHg, and static underpressures: –25, –45, –75 mmHg. The subsequent images were taken after stabilization of pressure on a set level. The applied research method shows that the nano-coating of 30 nm in thickness significantly affects deformation of the blood chamber of Religa Heart_Ext in macro scale. The proposed composition of coatings increases strain on external surface of the ventricular assist device.
2
Content available remote IR and microscopic studies of polyurethane surface in the Polish extracorporeal ventricular assist device POLVAD-MEV
Kościelniak-Ziemniak M., Hajduk B., Jarka P., Weszka J., Kustosz R., Kapis A., Gonsior M.
Archives of Materials Science and Engineering
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2014
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Vol. 68, nr 1
10--19
EN
Purpose: The aim of this article is to show results of IR measurements and microscopic analysis performed on layers prepared with dissolved VAD fragments and pieces of ventricular assist devices cut out of from determined VAD sectors. Design/methodology/approach: The objects of the study have been POLVAD-MEV VADs from POLCAS system. Four ventricular assist devices POLVAD-MEV have been investigated with use M80 SPECORD IR spectrophotometer and high sensitivity Zeiss – 5 Exciter Confocal Laser Scanning Microscope equipped with a CCD camera. Findings: The carried IR and microscopic studies showed changes of VAD inner surface. All VAD polyurethane fragments had lower or higher degree of degradation, which isn’t directly connected with implantation time. Research limitations/implications: The polyurethane degradation and surface damage is probably connected with its hydrolysis. The potential effect of blood interaction with VAD inner surface was discussed. Originality/value: of this paper is spectrophotometer and microscopic studies of polyurethane surface in the polish extracorporeal ventricular assist device POLVAD-MEV.
3
Content available Acoustic System of Determining the Instantaneous Volume of the Blood Part of the Ventricular Assist Device POLVAD-EXT
Konieczny G., Pustelny T., Opilski Z., Gawlikowski M.
Archives of Acoustics
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2014
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Vol. 39, No. 4
541--548
EN
The paper presents the results of investigations concerning the noninvasive method of estimating the actual volume of the blood chamber of the POLVAD-EXT type ventricular assist device (VAD) during its operation. The proposed method is based on the principle of Helmholtz’s acoustic resonance. Both the theory, main stages of the development of the measurement method as well as the practical implementation of the proposed method in the physical model of the POLVAD-EXT device are dealt with. The paper contains the results of static measurements by means of the proposed method (conducted at the Department of Optoelectronics, Silesian University of Technology) as well as the dynamic measurements taken at the Foundation of Cardiac Surgery Development (Zabrze, Poland) with the professional model of the human cardiovascular system. The results of these measurements prove that the proposed method allows to estimate the actual blood chamber volume with uncertainties below 10%.
4
Content available Hybrid system of ECG signal acquisition and QRS complexes detection for special medical devices synchronization
Komorowski D., Malcher A., Pietraszek S.
Journal of Medical Informatics & Technologies
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2013
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Vol. 22
227--234
EN
Some medical devices such as mechanical circulatory support systems and defibrillators require synchronization with the appropriate phase of the cardiac cycle of the patient. This paper presents a description of the electrocardiographic (ECG) signal amplifier and QRS detector designed for use with such devices. The detector system was built using a programmable analog array AN231E04 and the ECG amplifier with an analog-digital (A/D) converter based on a programmable circuit (front-end) ADS129x. By using the programmable elements and exploiting the potential of dynamic analog matrix reconfiguration, the presented detector achieved the desired features, such as low latency of QRS detection, automatic gain control and the ability to change the time constant by software. High-resolution of the A/D converter in the ADS1298x and the possibility of programming the gain of the amplifier allow the acquisition of the ECG signal acquired from different types of electrodes: disposable standard, epicardial or endocavitary. The tests of the prototype system proved that it is highly effective for the detection of QRS complexes in ECG waveforms recorded from all kinds of electrodes.
5
Content available Determination of stroke volume of the ventricular assist device using bioimpedance method
Sobotnicki A., Gacek A., Pałko T., Mocha J., Badura G., Czerw M.
Journal of Medical Informatics & Technologies
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2013
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Vol. 22
235--241
EN
The stroke volume of pulsatile ventricular assist device (VAD) is one of the key clinical indicators to evaluate the adequacy of the process of mechanical heart assistance and ensuring the patient’s safety. In order to evaluate the volume changes in VAD blood chamber, a bioimpedance method was applied, based on volumetric electric conductivity of the blood. Periodic changes in VAD volume during its operation result in a pulsatile impedance waveform; its amplitude in the subperiods of filling and ejection correlates with blood volume in the chamber. The paper presents the method of analysis of the bioimpedance signal recorded in VAD blood chamber with a reference to the classical method of analysing the cardioimpedance signal from the patient’s thorax. The paper also presents the results of determining stroke volume of blood chamber based on an empirical formula that has been developed.
6
Content available A study on permanent magnet topologies for hybrid bearings for medical drives applied in Ventricular Assist Devices
Pohlmann A., Hameyer K.
Archives of Electrical Engineering
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2011
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Vol. 60, nr 3
371-380
EN
In industrialized countries cardiovascular diseases are the major cause of death. The last clinical therapy option for some patients, suffering from terminal heart diseases, is donor heart transplantation. As the available number of donor organs is decreasing, many patients die while waiting for a transplant. For this reason Ventricular Assist Devices (VADs), which can mechanically support the human heart to achieve a sufficient perfusion of the body, are under development. For an implantable VAD, design constraints have to be deduced from the physiological conditions in the human body. In case of a VAD drive, these constraints are for example dimensions, electric losses, which might result in an overheating of blood, and a long durability. Therefore a hybrid permanent magnet hydrodynamic bearing is designed in this paper, which works passively and contactless. Based on Finite Element simulations of magnetic fields, various permanent magnet topologies are studied in terms of axial forces and stiffness.
7
Content available QRS complexes detector for synchronization of ventricular assist device
Mocha J., Sobotnicki A., Czerw M., Gibiński P.
Journal of Medical Informatics & Technologies
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2010
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Vol. 16
35--41
EN
Synchronization of operation of an artificial chamber supporting the sick heart of a patient has a crucial meaning for the effectiveness of support. To make the synchronized operation possible, the information on patient's heart activity should be fed to a controller of the supporting chamber. To this end, the QRS complex detector operating on ECG signal is necessary. The signal must be acquired from a patient's heart. Appropriate signal quality at long-term support may be assured only in a case the signal is acquired with epicardial electrodes. In the paper, the concept of hardware construction of a QRS complex detector has been presented, based on a field programmable analog array FPAA. The results of verification of the developed detector include the correct operation while using the epicardial signals recorded from patients which undergone the cardiosurgical operations.
8
Szkło dla fotoniki. Cz. 16, Synteza szkła światłowodowego metodą hydrolizy płomieniowej
Romaniuk R.
Elektronika : konstrukcje, technologie, zastosowania
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2010
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Vol. 51, nr 1
133-139
PL
Szkła, obok półprzewodników i metali są podstawowym materiałem do budowy elementów w optoelektronice i mikroelektronice. Praktyczna wiedza o szkłach rozszerza się wraz z silnym rozwojem ich zastosowań w telekomunikacji, czujnikach i budowie mikrosystemów. Wiele elementów funkcjonalnych fotoniki, budowanych jest ze szkieł laserowych. Optyczne zjawiska nieliniowe indukowane w szkle pozwalają na budowę nowych mikroelementów fotonicznych zastępujących złożone rozwiązania klasycznej optyki objętościowej. Szkła gradientowe zastępują klasyczne szkła optyczne. W artykule przedstawiono główną metodę wytwarzania ultraczystego, niskostratnego, wysokokrzemionkowego, słabo domieszkowanego szkła światłowodowego. Wysokotemperaturowa metoda syntezy szkła metodą hydrolizy płomieniowej jest najpowszechniej stosowana. Posiada kilka odmian: wewnętrzną, zewnętrzną i osiową. Metoda osiowego przyrostu preformy szklanej pozwala na jej produkcję metodą ciągłą. Uzyskuje się także najlepsze parametry szkła. Omówiono szerzej metodę VAD.
EN
Glasses, together with semiconductors and metals, are fundamental materials for building of components for optoelectronics and microelectronics. Practical knowledge about glasses extends considerably with strong development of their applications in telecommunications, sensors and the construction of microsystems. Many functional components of the photonics is manufactured of laser glasses. Nonlinear optical phenomena induced in glasses allow for building of new microcomponents, replacing complex solutions of classical volume optics. Gradient glasses are replacing classical optical glasses. The paper, which is the sixteenth part of a cycle on glasses for photonics, presents the major method of ultrapure, low-loss, high-silica, weakly doped, optical fiber glass manufacturing. High temperature glass synthesis by flame hydrolysis is the most frequently used one. It has several versions: inside, outside and axial. The axial method allows for continuous growth of the preform. The obtained glass parameters by VAD method are the best. VAD method was closer presented.
9
Szkło dla fotoniki. Cz. 15, Synteza szkła światłowodowego z fazy gazowej
Romaniuk R.
Elektronika : konstrukcje, technologie, zastosowania
|
2009
|
Vol. 50, nr 12
137-143
PL
Szkła, obok półprzewodników i metali są podstawowym materiałem do budowy elementów w optoelektronice i mikroelektronice. Praktyczna wiedza o szkłach rozszerza się wraz z silnym rozwojem ich zastosowań w telekomunikacji, czujnikach i budowie mikrosystemów. Wiele elementów funkcjonalnych fotoniki budowanych jest ze szkieł laserowych. Optyczne zjawiska nieliniowe indukowane w szkle pozwalają na budowę nowych mikro-elementów fotonicznych zastępujących złożone rozwiązania klasycznej optyki objętościowej. Szkła gradientowe zastępują klasyczne szkła optyczne. W artykule, który jest piętnastą częścią cyklu prac o szkłach dla fotoniki, przedstawiono główną grupę metod wytwarzania ultraczystego, niskostratnego, wysokokrzemionkowego, słabo domieszkowanego szkła światłowodowego. Wysokotemperaturowa metoda syntezy szkła metodą utleniania lub hydrolizy płomieniowej halogenków jest najpowszechniej stosowana. Posiada kilka odmian: płomieniową, plazmową, wewnętrzną, zewnętrzną i osiową. Metoda osiowego przyrostu preformy szklanej pozwala na jej produkcję przemysłową metodą ciągłą. Omówiono szerzej modyfikowaną metodę CVD.
EN
Glasses, together with semiconductors and metals, are fundamental materials for building of components for optoelectronics and microelectronics. Practical knowledge about glasses extends considerably with strong development of their applications in telecommunications, sensors and the construction of microsystems. Many functional components of the photonics is manufactured of laser glasses. Nonlinear optical phenomena induced in glasses allow for building of new microcomponents, replacing complex solutions of classical volume optics. Gradient glasses are replacing classical optical glasses. The paper, which is the fifteenth part of a cycle on glasses for photonics, presents the major group of methods of ultrapure, Iow-loss, high-silica, weakly doped, optical fiber glass manufacturing. High temperature glass synthesis by halide oxidation or flame hydrolysis is the most frequently used one. It has several versions: flame, plasma torch, inside, outside and axial. The axial method allows for continuous growth of the preform and is suitable for industry. MCVD method is presented in details.
10
Content available remote Current states of small and lightweight pulsatile motor driven LVAD
Okamoto E., Tanaka S., Makino T., Miura K., Okada S., Mitoh A., Mitamura Y.
Biocybernetics and Biomedical Engineering
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2007
|
Vol. 27, no. 1-2
155-160
EN
A small size and lightweight motor-driven pulsatile LVAD using a ball screw has been developed. The motor-driven LVAD consists of a brushless DC motor and a ball-screw. The ball screw converts rotational motion of the motor into rectilinear motion of the pusher plate. The magnetic force between the tiny magnets on the pusher plate and the iron plate adhered on the pump diaphragm provides an active filling operation during the pump filling phase. The pump has a stroke volume of 55 ml, the whole volume of 285 ml and it weighs 360 g. The controller employs the fuzzy logic position and velocity control so that the LVAD experts’ experience could be used in the design of the controller. The LVAD was evaluated in the in-vitro experiments using the mock circulation. Maximum pump outflow of 5.1 l/min was obtained at the drive rate of 100 bpm against an afterload of 100 mmHg, and the active filling mechanism using the magnetic force provided a pump output of 3.6 l/min at a drive rate of 75 bpm under a preload of 0 mmHg. The operating efficiency of the LVAD was established to be measured between 8 and10%.
11
Content available remote Basic parameters in speech processing. The need for evaluation
Höge H.
Archives of Acoustics
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2007
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Vol. 32, No. 1
67-74
EN
As basic parameters in speech processing we regard pitch, duration, intensity, voice quality, signal to noise ratio, voice activity detection and strength of Lombard effect. Taking in account also adverse conditions the performance of many published algorithms to extract those parameters from the speech signal automatically is not known. A framework based on competitive evaluation is proposed to push algorithmic research and to make progress comparable.
12
Content available remote Development of implantable assist pump and its peripheral devices
Okamoto E., Makino T., Yamamoto Y., Asao H., Watanabe N., Nakamura M., Tanaka S., Inoue Y., Yasuda T., Mitamura Y.
Biocybernetics and Biomedical Engineering
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2006
|
Vol. 26, no. 1
45-51
EN
Two national project for development of an artificial heart system are being undertaken in Japan, and Hokkaido Tokai University has taken part in both national projects in order to develop peripheral devices of an implantable VAD (ventricular assist device) system. Each of the peripheral devices incIudes a transcutaneous energy transmission system, an internal battery system, and a transcutaneous information transmission system. Maximum energy transmission efficiency of the transcutaneous energy transmission system is over 85% (DC to DC) at an energy transmission ratio of 25 W. The internal battery system mainly consists of three lithium ion batteries, a charge circuit, and a power interface (case size of 11Ox80x30 mm). The internal battery system can drive a VAD for over 2 hours with maximum battery case surface temperature of 43°C. The information transmission system (diameter of 52 mm and thickness of 12 mm) mainly consists of an ASK modulator and an ASK demodulator employing carrier frequencies of 4 MHz and 10 MHz. It can transmit data electromagnetically between inside and outside of the body bi-directionally at a data transmission ratio of 56 kbps. Long-term animal experiments showed that each peripheral device has adequate performance to support the operation of implantable VAD.
13
Content available remote Influence of the inlet and outlet compliance on the effectiveness and work safety of a pneumatically-driven paracorporeal prosthetic ventricle
Paszkowski M., Nawrat Z.
Acta of Bioengineering and Biomechanics
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2005
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Vol. 7, nr 2
40-50
EN
The paper deals with the problems connected with mechanical assistance to cardiovascular system by means of the pneumatically driven artificial ventricle POLVAD-MEV and, more precisely, the influence of the pump elements' compliance being placed directly in the front of the inflow valve (inlet compliance) and behind the outflow valve (outlet compliance) on the effectiveness and safety of this assistance. The authors concentrated mainly on the changes in the output flow of the aniflcial ventricle and inertia phenomena (water-hammer effect) occurring together with different values of the compliance. All experiments were carried out in the Biocybernetics Laboratory of the Institute of Heart Prostheses in Cardiac Surgery Development Foundation in Zabrze by means of a mock circulation and a physical model of the inlet and outlet compliance.
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