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1
Content available remote Frequency indexes of respiration during interrupter experiment
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EN
A new issue of the respiratory mechanics evaluation by the frequency mode of the interrupter technique is undertaken in the paper. The aim of the computer-aided research is to show the abilities to separate airways and tissue properties of the respiratory system. The proposed evaluation procedure of the identification quality in the modified DuBois model proves the possibility to conduct repeatable measurements of the important diagnostic indexes. The obtained precision of the parametric description of the investigated physiological system suggests the need to continue the work in the outlined direction. Their final effect can be a portable device with applicability to clinically diffcult subjects - infants and pre-school children.
2
Content available remote A forward model of the respiratory system during airflow interruption
100%
EN
The paper presents a methodology of complex electrical model formulation for the respiratory system during airflow interruption. Adequacy of both structural and parametric description to the real physiological system has been taken care of. Properties of the valve-transducer unit, upper airways, bronchial tree, lung tissue chest wall and abdomen have been noted in an equivalent description of the electrical circuit. The resulting analog, combining more than 180 parameters, gives the possibility to imitate conditions of normal breathing and airflow interruption. A qualitative verification of the model has been conducted in the time and frequency domain, based on reported numerous experimental findings. The proposed linear description of the respiratory system can be the source of synthetic data for a verification of the interrupter method and for the procedure of model reduction to its identifiable form.
EN
A complex model of mechanically ventilated ARDS lungs is proposed in the paper. This analogue is based on a combination of four components that describe breathing mechanics: morphology, mechanical properties of surfactant, tissue and chest wall characteristics. Physical-mathematical formulas attained from experimental data have been translated into their electrical equivalents and implemented in MultiSim software. To examine the adequacy of the forward model to the properties and behaviour of mechanically ventilated lungs in patients with ARDS symptoms, several computer simulations have been performed and reported in the paper. Inhomogeneous characteristics observed in the physical properties of ARDS lungs were mapped in a multi-lobe model and the measured outputs were compared with the data from physiological reports. In this way clinicians and scientists can obtain the knowledge on the moment of airway zone reopening/closure expressed as a function of pressure, volume or even time. In the paper, these trends were assessed for inhomogeneous distributions (proper for ARDS) of surfactant properties and airway geometry in consecutive lung lobes. The proposed model enables monitoring of temporal alveolar dynamics in successive lobes as well as those occurring at a higher level of lung structure organization, i.e. in a point P0 which can be used for collection of respiratory data during indirect management of recruitment/de-recruitment processes in ARDS lungs. The complex model and synthetic data generated for various parametrization scenarios make possible prospective studies on designing an indirect mode of alveolar zone management, i.e. with a minimized risk of repeated alveolar recruitment/de-recruitment and mechanical overstraining of lung tissues.
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tom R. 59, nr 3
266--269
PL
Przedmiotem publikacji jest przedstawienie propozycji modelowania i zasad wizualizacji zmian w mechanice układu oddechowego, u osób z nadwagą lub otyłością. W badaniach wykorzystano 16-elementowy model elektryczny układu oddechowego. Dobór wartości parametrów modelu odbywał się na podstawie wiedzy dostępnej w literaturze medycznej. Opracowanie może być szczególnie przydatne inżynierom dokonującym wstępnej weryfikacji nowo opracowywanych systemów medycznych lub na etapie dokonywania przeglądów okresowych aparatury medycznej.
EN
The subject of the publication is a proposal of approach to modeling and visualization of changes in pulmonary mechanics, for people impaired by obesity or serious overweight. Previously developed models of the patient respiratory system were based on parameter identification of the considered models with the help of the measured data [3]. In this paper the modeling procedures basing on the basic medical knowledge in the field of clinical obesity (BMI> 35) are proposed. In the research a 16-coefficient electrical model of the respiratory system (Fig. 1), presented previously in [8], was used Most of lesions causing the changes in parameter values, described in Section 2, simulate the changes in mechanics of respiratory tract and lungs. The range and nature of the changes in the model parameter values are the subject of Section 3. The results of simulations of the respiratory volume (Fig. 3) and the flow (Fig. 4) are presented in Section 4. Moreover, the result of respiratory mechanics examination obtained by FOT is shown in Fig. 6. The presented time courses are consistent with the results available in the medical literature, obtained as a result of the medical examinations (Fig. 5). That proves the legitimacy of the presented approach and demonstrates the functionality of lesions modeling based on basic medical knowledge. This approach may be particularly useful for engineers providing preliminary verification of newly developed medical systems or at the stage of servicing the medical equipment.
PL
Założenia wstępne formułujące ideę nieinwazyjnego algorytmu przerywanego przepływu powietrza, dedykowanego do pomiaru mechaniki oddychania, prowadzą do istotnych przeszacowań indeksu diagnostycznego (Rint) w bazowej wersji metody. Zasadniczym źródłem ograniczenia są prosta (jednoelementowa) fizyko-matematyczna reprezentacja systemu oraz stosowany algorytm (ekstrapolacji wstecznej) przetwarzania danych eksperymentalnych. W artykule, najpierw w sposób analityczny a następnie w drodze symulacji komputerowych, wykazano możliwość separacji składowych odpowiedzi z tkanek płuc i dróg oddechowych. Ponadto, w sposób ilościowy pokazano udział oporu klatki piersiowej w całkowitej odpowiedzi systemu na quasi-skokowe pobudzenie zaworem przerwaniowym. Uzyskane wyniki są elementem pośredniczącym w przejściu pomiędzy klasyczną i wzbogaconą wersją algorytmu okluzyjnego.
EN
Preliminary assumptions postulated for the idea of the airflow interrupter technique, dedicated for respiratory mechanics measurement, lead to significant overestimation of the diagnostic index (Rjnt) in a basal version of the method. Essential sources of that limitation are simple (one-element) physical-mathematical representation of the system and the back-extrapolative algorithm used for experimental data processing. Analytic considerations have been firstly provided in the paper and next the possibility to separate airway and tissue component in the pressure-flow outpul has been shown during airflow interruption using computer simulation. Moreover, quantitative assessment of thoracic loading in the resistive response of the system on quasi-step excitation by valve closing has been documented. Results can be perceived as a linkage between the classical and enhanced version of the occlusional algorithm.
7
Content available remote Simulation on human respiratory motion dynamics and platform construction
63%
EN
Bronchoscopy has a crucial role in the current treatment of lung diseases, and it is typical of interventional medical instruments led by manual intervention. The scientific study of bronchoscopy is now of primary importance in eliminating problems associated with manual intervention by scientific means. However, for its intervention environment, the trachea is often treated statically, without considering the effect of tracheal deformation on bronchoscopic intervention during respiratory motion. Therefore its findings can deviate from practical application. Thus, studying kinetic problems in respiratory motion is of great importance. This paper developed a mathematical model of mechanical properties of respiratory motion to express respiratory force from the perspective of dynamics of respiratory motion. The dynamical model was solved using MATLAB. Then, a finite element model of respiratory motion was built using Mimics, and the results of respiratory force solution were used as the load of model for dynamics simulation in ABAQUS. Then, a human–computer interaction platform was designed in MATLAB APP Designer to realize parametric calculation and fitting of respiratory force, and a personalized human respiratory motion dynamics simulation was completed in conjunction with ABAQUS. Finally, experimental validation of the interactive platform was performed using pulmonary function test data from three patients. Validation analysis by respiration striving solution, kinetic simulation and experiment found that Dynamical model and simulation results can be better adapted to the individualized study of human respiratory motion dynamics.
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