Wyniki wyszukiwania - Biblioteka Nauki

1

Wirtualny układ oddechowy i jego wykorzystanie w testowaniu metod sztucznej wentylacji i wspomagania oddychania

100%

Gólczewski T. , Darowski M.

Bio-Algorithms and Med-Systems

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2005

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tom Vol. 1, no. 1/2

65--71

PL

Problemy techniczne, ekonomiczne oraz wzrastające znaczenie kwestii etycznych powodują, że wykorzystanie w badaniach naukowych wirtualnych organów może okazać się bardziej wygodne niż eksperymenty na zwierzętach czy ograniczone możliwości wykorzystania pacjentów w badaniach. W szczególności wirtualny układ oddechowy (WUO) może być użyteczny w testowaniu respiratorów i nowych metod wspomagania, w edukacji i treningu personelu, a także we wstępnym testowaniu hipotez naukowych. W pracy przedstawiono: (1) ideę WUO, (2) weryfikację za pomocą standardowej spirometrii (wyników symulacji nie można odróżnić od wyników otrzymanych dla realnych pacjentów), (3) przykłady wykorzystania WUO w: (a) porównaniu zagrożeń dla zdrowia podczas różnych trybów sztucznej wentylacji, (b) analizie konieczności stosowania niezależnej wentylacji płuc, (c) analizie skuteczności wspomagania oddychania metodą CPAP w obturacyjnej chorobie płuc.

EN

Economic, technical and ethical problems may render the use of virtual organs in investigations more convenient than experiments on animals or limited investigations on patients. In particular, Virtual Respiratory System (VRS) may be useful for tasks such as respirator and support methods testing, education, staff (medical & technical) training, (initial) testing of scientific hypotheses, etc. The paper presents: (1) the VRS idea, (2) verification with standard spirometric examination (it is impossible to distinguish between results for real patients and VRS, which confirms VRS reliability), (3) examples of the use of VRS in: (a) comparison of health hazard in ventilation of different modes, (b) analysis of necessity of differential ventilation, (c) analysis of efficiency of support with CPAP in obstructive lung disease.

2

The virtual cardio-respiratory system: a sub-model of gas exchange and transfer

100%

Gólczewski T. , Darowski M.

Biocybernetics and Biomedical Engineering

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2008

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tom Vol. 28, no. 1

29-40

EN

A virtual cardio-respiratory system (CRS) is proposed for testing ventilatory support and scientific hypothesis. It may appear more convenient than experiments on animals or limited investigations on patients. In particular, there are no limitations for manipulation of virtual CRS parameters while such manipulation is difficult or impossible in the case of real CRS. The virtual CRS architecture: The proposed virtual CRS consists of: (a) the sub-model of respiratory system mechanics (RSM) previously used as the stand-alone virtual respiratory system, (b) a sub-model of gas exchange and transfer in the respiratory and circulatory systems (GET), which is constituted with three modules: gas transfer in respiratory system, gas exchange in lungs, and gas transfer in circulation. The GET utilizes airflows and pressures supplied by the RSM whereas the RSM utilizes volumes of gases supplied by the GET. Results: the CRS gave proper results for both respiration and respiratory arrest. In particular, if the CRS 'respired' with pure oxygen then arterial blood saturation with oxygen remained high for tens of minutes after respiratory halt when airways were open; otherwise atelectasis developed during 8-10 minutes. Like for real patients, carbon dioxide tension in blood decreased quickly when ventilation increased and it increased slowly when the ventilation fell.

3

Lung mechanics measurement independent on ventilatory treatment

100%

Darowski M. , Kozarski M.

Biocybernetics and Biomedical Engineering

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2002

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tom Vol. 22, no. 4

115-121

EN

A new method of lungs mechanics calculation has been developed, which is independent on the method of ventilatory support and may be used automatically during long-term treatment. Lungs compliance assessment is based on the periodical measurements od airway pressure during expiration. Airways resistance is calculated from expiratory time constant. The results of preliminary, model studies showed that proposed method has a clinically acceptable accuracy and can be performed by a separate instrument, independent on a type of the respirator used.

4

Influence of ventilatory mode on respiration parameters - investigation on virtual lungs

100%

Gólczewski T. , Darowski M.

Biocybernetics and Biomedical Engineering

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2003

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tom Vol. 23, no. 3

63-72

EN

In the paper influence of different artificial ventilation modes (pressure-controlled, volume-controlled with constant and with decelerating flow, and power-controlled, i.e. adaptive) on chosen respiratory parameters (peak and mean pressure in lungs, peak gas flow, distribution of lungs ventilation) were analyzed in cases of permanent and sudden obstruction. The comparison has proved that the adaptive mode generally has some advantages over routinely used ventilatory modes, if influence on all the respiratory parameters together is taken into account: all the parameters achieve moderate values for the adaptive mode, while at least one parameter achieves a big value for each other mode. Thus, the adaptive mode causes the smallest total health hazard.

5

EtCO2 -Based Biofeedback Method of Breath Regulation Increases Speech Fluency of Stuttering People

80%

Stankiewicz B. , Zieliński K. , Darowski M. , Michnikowski M.

Archives of Acoustics

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2015

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tom Vol. 40, No. 4

469–-474

EN

Respiratory disturbances frequently accompany stuttering. Their influence on lung ventilation can be assessed by measurement of the end-tidal CO2 concentration (EtCO2). The effectiveness of the CO2-based visual feedback method of breath regulation (VF) designed for stuttering therapy was tested in this study. The aim of the study was to answer the question if the VF helps to reduce respiratory disturbances in stuttering and increase speech fluency. 20 stuttering volunteers aged 13–45 years took part in the 3-parts test consisting of: 1. speaking without any techniques improving speech fluency, 2. learning the VF method, 3. VF-assisted speaking. The CO2/time signal and an acoustic signal of an utterance were recorded during the test. Significant increase of FE – the factor of breath ergonomics during speaking (based on both signals), from 47% to 71% (P < 0.01), and significant decrease of %SS – the percent of syllables stuttered, from 14% to 10% (P < 0.01) were received for VF-assisted utterances compared to the utterances without VF assistance. The results indicate that the VF can help to eliminate respiratory disturbances in stuttering and increase speech fluency.

6

Visual feedback based on expired CO2 as a therapy method for respiratory disturbances in stuttering

80%

Stankiewicz B. , Adamczyk B. , Zieliński K. , Darowski M.

Archives of Acoustics

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2006

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tom Vol. 31, No. 4

439-444

EN

A new CO2-based visual feedback therapy method (VF) for respiratory disturbances in stuttering was preliminarily assessed. Sound and expired CO2 signals were registered in 12 stutterers and 12 fluent speakers while speaking without and with VF to control breathing as well as during rest respiration, before each utterance. In stutterers, the end-tidal CO2 (ETCO2), the area under CO2/a time curve (SCO2), and the average emission of CO2 (ECO2 = SCO2/tbreath_cycle) for the CO2 peaks connected with the phrases containing tonic errors (with reference to rest respiration) were higher than those connected with fluent phrases (p<0.000001). Thus, a tendency to hypoventilation caused by tonic errors was observed. The factors of breath ergonomics while speaking FE (based on both signals) of stutterers were lower than those in fluent speakers (p<0.001). Using VF by stutterers increased FE (p<0.005) and decreased stuttering intensity.

7

Cardiovascular, respiratory and veno-lymphatic assistance. Modelling and simulation

80%

Górczyńska K. , Darowski M. , Kozarski M.

Biocybernetics and Biomedical Engineering

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2002

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tom Vol. 22, no. 2-3

135-175

EN

In the paper some problems concerning investigations conducted at Bioflows Departament of the Institute of Biocybernetics and Biomedical Engineering on cardiovascular , respiratory and veno-lymphatic assistance have been discussed. The investigations were mainly focused on modelling of cardiovascular and respiratory systems, cardiopulmonary interaction and veno-lymphatic non-invasive support. The results of physical and computer simulation of cardiopulmonary assistance and clinical results of veno-lymphatic support studies have been presented.

8

Expiratory pressure curve analysis for estimation of lungs mechanics

80%

Darowski M. , Pałko T. , Jucha A. , Kozarski M.

Biocybernetics and Biomedical Engineering

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2003

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tom Vol. 23, no. 1

91-102

EN

The analysis of an expiratory pressure curve by using an extra small pneumatic compliance is presented in this paper. The investigations of dynamic courses were performed for a very short time (<200 ms), and basic mechanical parameters of lungs were calculated. For analysis of measurement signals and monitoring of measurement circuit a new computer system was used. The measurement circuit was based on mechanical lungs model. The results of studies have shown that the applied method can be used for estimation of lungs compliance but to determine an airway resistance from the time constant an additional measurement of the flow rate curve is needed. The discussed method of lungs mechanics estimation in independent of ventilatory support.

9

Feedback-controlled independent lung ventilation - model studies

80%

Glapiński J. , Darowski M. , Marraro G. A. , Luchetti M.

Biocybernetics and Biomedical Engineering

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2003

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tom Vol. 23, no. 3

55-62

EN

A feedback-controlled unit for independent lungs ventilation has been developed and tested. This device can be used to ventilate both lungs separately using only one ventilator. Using this flow divider we can apply different PEEP pressures in each lung, and independetly achieve different tidal volumes.

10

The respirator as a user of virtual lungs

80%

Gólczewski T. , Kozarski M. , Darowski M.

Biocybernetics and Biomedical Engineering

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2003

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tom Vol. 23, no. 2

57-66

EN

The virtual respiratory system (VRS) is proposed for testing physical respirators, new methods of ventilatory support, and scientific hypotheses. VRS may be also helpful in students education and staff training. Method: VRS simulates the relationship between the air flow and the pressure. The main features of the model are: separation of the lungs and the chest, division of the lungs into five lobes, closing bronchi, gravity influence. Real-to-virtual converter is based on the gas flow source, which is controlled by the calculated value of the air flow that should exist, for the measured pressure being the VRS input. Results: several phenomena are discussed, e.g. the influence of compliance nonlinearity and resistance changeability on ventilation, the CPAP efficiency, differences in lobes ventilation, breathing frequency determination.

11

The electropneumatic gyrator as a tool for physical modeling of lungs

80%

Kozarski M. , Maras K. , Darowski M. , Pałko K. J.

Biocybernetics and Biomedical Engineering

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2003

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tom Vol. 23, no. 3

47-54

EN

Unlike classical physical lung models, the model presented in the paper makes it possible to realize any input impedance of lungs representing their complex mechanical structure. The crucial element of the model is the electropneumatic gyrator converting the input impedance of the electrical network, connected to electrical ports of the gyrator, into the inversely proportional pneumatic impedance obtained in its pneumatic channel. The gyrator is built up as a cross-connection of electrically controlled flow and current sources. Experimental investigations demontrated a very good static and dynamic accuracy of the gyratory conversion. The characteristic pressure and flow courses illustrating dynamical behavior of the gyratory model of lungs are also included.

12

A family of circulatory computer models developed to analyse and predict physiopathological events: applications to mechanical circulatory and ventilatory assistance

80%

De Lazzari C. , Darowski M. , Ferrari G. , Tosti G.

Biocybernetics and Biomedical Engineering

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2006

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tom Vol. 26, no. 2

25-37

EN

The aim of this work is to present a family of circulatory computer models suitable to be used for analysis and prediction. Circulatory models can reproduce many circulatory phenomena for several practical applications referable to the main functional sectors of analysis and prediction. Of course, the models are different in relation to the phenomena to be represented. An important issue is the possibility to represent the artero-ventricular interactions and the effects, in different ventricular conditions, of the influence of mechanical ventilatory and circulatory assistance. In these models of human cardiovascular system, the influence of mechanical ventilation was introduced, changing the thoracic pressure to positive values. In the work, two different applications were presented: in the first one the trends of the haemodynamic variables were analysed when mechanical ventilation of the lungs was applied for different values of mean intrathoracic pressure. In the second application, were presented the effects on the haemodynamic variables of the left ventricular assist device (in particular arotary blood pump).

13

Choice of proper lung ventilation method

80%

Darowski M. , Gólczewski T. , Michnikowski M.

Biocybernetics and Biomedical Engineering

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2006

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tom Vol. 26, no. 1

21-37

EN

In the article three different methods of lung ventilation have been analyzed: Continuous Positive Airways Pressure (CPAP), Proportional Assist Ventilation (PAV) and Pressure Support Ventilation (PSV). The aim of these analyses was to predict clinical situations when the considered modes of ventilation would play their role in the best, optimal way. The study on effective ventilatory support by CPAP, PAV and PSY was conducted using virtual respiratory system - a new, but yet verified model of the system, recently developed by our group. Computer simulation, done on a healthy lung model and on a pathologically changed lung model, has clearly shown the conditions under which CPAP, PAV or PSY could be really effective. CPAP is worth using in patients with a high airways resistance, in which case this mode of ventilatory support ensures breathing with normal frequency and less energy-consuming inspiration. PAV usually results in a smaller peak and the mean alveolar pressure than PSY which decreases a potentially harmful effect of the positive pressure ventilation on the cardiovascular system. On the other hand, PAV may be used safely when estimation of the parameters such as the lung/thorax compliance and the airway resistance is reliable, since the setting of the supporting pressure is based on this estimation.

14

Model eliminacji CO2 z przestrzeni pecherzykowej

80%

Darowski M. , Szczepanik M. , Rudowski R. , Englisz M.

Działalność Naukowa PAN. Wybrane Zagadnienia

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1998

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tom 05

121-123

15

Urządzenie ECP-100 do nieinwazyjnego wspomagania układu krążenia wykorzystujące metodę kontrpulsacji zewnętrznej

80%

Bachorz M. , Godecki M. , Darowski M. , Kozarski M.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2009

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tom Vol. 15, nr 1

52-53

PL

Urządzenie ECP-100, opracowane przez ITAM Zabrze przy współpracy z 1B1B PAN Warszawa, umożliwia terapię pacjentów z chorobą niedokrwienną serca. Podczas zabiegu pacjent z zestawem mankietów pneumatycznych spoczywa na leżu zabiegowym. Zestaw składa się z trzech mankietów (podobnych do tych stosowanych przy pomiarze ciśnienia), które są owinięte dookoła łydek, ud i pośladków. Mankiety są napełniane sekwencyjnie na początku fazy rozkurczu serca i opróżniane przed fazą skurczu. Napełnianie i opróżnianie mankietów jest zsynchronizowane z przebiegiem EKG, tak by zoptymalizować korzyści terapeutyczne.

16

A PC based model to simulate artero-ventricular interaction and the effect of mechanical circulatory and ventilatory support

71%

De Lazzari C. , Darowski M. , Clemente F. , Guaragno M. , Ferrari G.

Biocybernetics and Biomedical Engineering

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1999

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tom Vol. 19, no. 4

79-89

EN

A software package for the simulation of the cardiovascular system and of artero-ventricular interaction has been developed. It includes the reproduction of the effects of mechanical circulatory like Left Ventricular Assist Device (LVAD), Biventricular Assist Device (BVAD), Intra-aortic Balloon Pump (IABP) and ventilatory support systems. Lumped parameters models were used to reproduce the circulatory phenomena in terms of pressure and volume relationships. Variable elastance models reproduce the Starling's law of the heart, for each ventricle. LVAD and BVAD are inserted with atrial-arterial cannulation and can be synchronised with the onset of the natural ventricle systole. IABP model, inserted in the arterial tree, is considered as a flow source. Controlling the level of thoracic pressure (Pt) performs the simulation of mechanical ventilation. The examples of simulations are presented in the paper as the effects of LVAD and mechanical ventilatory support on circulatory system, in terms of hemodynamic parameters changes.

PL

W artykule przedstawiono model komputerowy CARDIOSIM@ i oprogramowanie do symulacji zależności hemodynamicznych w układzie sercowo-naczyniowym na komputerze zgodnym z PC. Oprogramowanie to umożliwia także symulację wpływu różnych metod mechanicznego wspomagania krążenia, np. sztucznej lewej komory serca (LVA]), wspomagania dwukomorowego (BVAD), lub pompy wewnątrzaortalnej (lABP) i oddychania na parametry hemodynamiczne i energetyczne. Modele LV AD, BVAD i IABP są zsynchronizowane z pracą naturalnej lewej komory serca (z początkiem fazy systolu). LVAD i BVAD są umieszczone równolegle z komorami serca, a IABP jest traktowane jako źródło przepływowe w tętniczej części modelu. Regulacja poziomu średniego, dodatniego ciśnienia w klatce piersiowej w modelu oddaje wpływ sztucznej wentylacji płuc na układ sercowo-naczyniowy. Model komputerowy opisujący zależności ciśnieniowo-przepływowe w poszczególnych częściach układu sercowo-naczyniowego jest modelem liniowym o staIych skupionych. Do opisu własności każdej z komór serca wg prawa Starlinga wykorzystano model zmiennej elastancji. W pracy przedstawiono przykłady symulacji komputerowej, jako cenną możliwość przewidywania wpływu stosowania LVAD i wspomagania oddychania na hemodynamikę.

17

Influence of ventilation mode on blood oxygenation - investigation with Polish Virtual Lungs and Italian Model of Circulation

71%

Gólczewski T. , Zieliński K. , Ferrari G. , Pałko K. J. , Darowski M.

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tom Vol. 30, no. 1

17-30

EN

Positive alveolar (PA) and thoracic (Pr) pressures during artificial ventilation disturb pulmonary circulation, and might influence arterial blood oxygenation (PaO2). Initial analysis of such influence of different artificial ventilation modes is the goal of this paper. Previously elaborated virtual respiratory system (IBIB PAS, Warsaw, Poland) and cardiovascular system model (ICP CNR, Rome, Italy) were connected with two files-buffers to work as one virtual cardio-pulmonary system. Dependence of PaO2 on two methods (continuous inspiratory airflow (VCV) or pressure (PCV)), two ventilatory frequencies (fV = 15 or 7.5/min), and two values of the minute ventilation (Vmin = 6 or 8L/min) was investigated. Perfusion dependence on gravity was neglected as the virtual patient was in the supine position. Simulations showed that when fV = 15/min, neither the used method nor Vmin influence pulmonary blood flow significantly, whereas they influence the flow during expiration when fV = 7.5 (blood flow falls more for PCV and Vmin = 8 L/min). Vmin more significantly influences alveolar partial pressure of oxygen (P02) when fV = l5/min. P02 was greater for PCV. As effects on the flow and PO2 were contradictory, Pa02 was almost independent of the used method and fV. It depended on Vmin more significantly if fV = 15/min.

18

Open loop hybrid circulatory model: the effect of the arterial lumped parameter loading structure on selected ventricular and circulatory variables

61%

Kozarski M. , Ferrari G. , Zieliński K. , Górczyńska K. , Pałko K. J. , Tokarz A. , Darowski M.

Biocybernetics and Biomedical Engineering

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2008

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tom Vol. 28, no. 1

17-27

EN

Different combinations of the artero-ventricular coupling design (numerical, physical and hybrid) and the arterial system structure (four-element standard, simplified, modified and three-element three-lump "ladder" Windkessel) have been applied in an open loop circulatory model to test their influence on selected ventricular and circulatory variables. Numerical investigations have shown that a four-element Windkessel with an introduced in series lumped inertance can evoke some numerical problems e.g. when combined with the simplified ventricular model containing "ideal" zero switching time heart valves or constant valve resistance during opening. The four-element Windkessel structure modification i.e. replacing the in series inertance by the parallel one, considerably improves the network match. Also the three-element three-lump "ladder" Windkessel has been found very useful in the blood circulation modelling thanks to relatively small input inertance and high input capacitance of its first lump.

19

Development of hybrid (numerical-physical) models of the cardiovascular system: numerical-electrical and numerical hydraulic applications

61%

Ferrari G. , Kozarski M. , De Lazzari C. , Górczyńska K. , Darowski M. , Tosti G.

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tom Vol. 25, no. 4

3-15

EN

Circulatory models are relevant to research, education and prosthetic devices/components testing. Their structure can be both numerical and physical, according to the specific needs. Numerical models are often developed first and then followed or accompanied by physical models. This approach is associated with higher costs, less accuracy and time-consuming development. Circulatory models defined as hybrid (merger of numerical and physical sections) can solve these problems. This paper presents two applications of the hybrid model with the physical section based on two different structures (electrical and hydraulic). The results show that the model can represent hemodynamic relationships in different circulatory conditions, including IABP assistance.

20

The electrohydraulic impedance converter in mock circulatory system design

61%

Kozarski M. , Ferrari G. , Darowski M. , Górczyńska K. , Clemente F. , Pałko K. J.

Biocybernetics and Biomedical Engineering

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2003

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tom Vol. 23, no. 2

27-34

EN

In the paper a new concept of a mock circulatory circuit design, utilizing the special impedance converter, i.e. the electrohydraulic gyrator, has been presented as well as basic theoretical considerations and simple examples of impedance conversions. Some results of experiments, illustrating physical and systemic features of the electrohydraulic gyrator, have been shown. A simple hybrid windkessel model has been investigated. Obtained results fully confirmed advantages of the presented new concept of a mock circulatory circuit design.