Pressure-Volume Controlled Mechanical Ventilator: Modeling and Simulation (original) (raw)
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A Mathematical Model of Lung Functionality using Pressure Signal for Volume-Controlled Ventilation
2020 IEEE International Conference on Automatic Control and Intelligent Systems (I2CACIS), 2020
Mechanical Ventilation is used to support the respiratory system malfunction by assisting recovery breathing process which could result from diseases and viruses such as pneumonia and COVID-19. Mathematical models are used to study and simulate the respiratory system supported by mechanical ventilation using different modes such as volumecontrolled ventilation (VCV). In this research, a single compartment lung model ventilated by VCV is developed during real time mechanical ventilation using pressure signal. This mathematical model describes the lung volume and compliance correctly considering positive end expiration pressure (PEEP) value. The model is implemented using LabVIEW tools and can be used to monitor the volume, flow and compliance as outputs of the model. Two experiments are carried out on the proposed lung model at three input scenarios of volume (400, 500 and 600 ml) for each experiment considering a PEEP value. To validate the model, an artificial lung connected to a VCV with the same scenarios is used. Validation check is conducted by comparing the outputs of the lung model to that of the artificial lung. The experimental results showed that the measured lung model outputs with negative feedback are the same for pressure and flow as the outputs without negative feedback, whereas the measured volume is comparatively lower for negative feedback. Average percent error in the experiment with negative feedback (5.14%) is smaller compared to the experiment without negative feedback (9.28%). Furthermore, the average error of the calculated compliance decreases from 16% (without negative feedback) to 2% (with negative feedback). The obtained results of the proposed method showed good performance and acceptable accuracy. Thus, the model facilitates the clinicians and practitioners as a training tool to learn real-time mechanical ventilation functionalities.
A simulation of a medical ventilator with a realistic lungs model
F1000Research, 2020
Background: The outbreak of COVID-19 pandemic highlighted the necessity for accessible and affordable medical ventilators for healthcare providers. To meet this challenge, researchers and engineers world-wide have embarked on an effort to design simple medical ventilators that can be easily distributed. This study provides a simulation model of a simple one-sensor controlled, medical ventilator system including a realistic lungs model and the synchronization between a patient breathing and the ventilator. This model can assist in the design and optimization of these newly developed systems. Methods: The model simulates the ventilator system suggested and built by the “Manshema” team which employs a positive-pressure controlled system, with air and oxygen inputs from a hospital external gas supply. The model was constructed using SimscapeTM (MathWorks®) and guidelines for building an equivalent model in OpenModelica software are suggested. The model implements an autonomously breathi...
Artificial Organs, 1995
Abstract: The patient submitted to artificial ventilation generally is connected to a high impedance flow source with controlled respiratory cycles to assure volume requirements or to a low impedance pressure source with spontaneous cycles to allow synchronization between his effort and system flow delivery. These two types of cycles represent the initial and final stages of artificial ventilation. The patient who needs a volume guarantee and at the same time presents unstable or insufficient inspiratory effort is difficult to manage with assisted cycles which are analogous to the controlled presence of a high impedance flow source. This paper presents a new approach where the respiratory cycles are obtained by the combination of flow and pressure sources using mathematical modeling. These cycles, named volume assisted pressure supported (VAPS) cycles, are compared with conventional assisted cycles showing a decrease in the patient work of breathing (WOB) during assisted ventilation. The theoretical results have been confirmed by clinical trials.
The growing interest in variable mechanical ventilation, known as noisy ventilation, motivated this work. The aim of which was to develop and test the new system, firstly on a bench setup and after in vivo. The first setup consisted of a mechanical ventilator, a mechanical lung simulator, a calibrated measuring device and a personal computer implementing the routine responsible for the noisy regime. The experiments were valuable to assess the behaviour of the new system and verify its use in vivo. Besides, an algorithm was developed to perform parameter estimation of the artificial respiratory system comprised of a mechanical lung simulator and air ways. The estimated parameters were: compliance, resistance and positive end-expiratory pressure (PEEP). To evaluate the correctness of the algorithm the parameters were adjusted directly on the bench system. The compliance was adjusted on the mechanical lung simulator, the resistance adjusted in the air ways and the PEEP adjusted on the mechanical ventilator. The assessment was based on the comparison between adjusted and estimated values. In the in vivo experiment conducted in an animal Intensive Care Unit (ICU) a pig was utilized. To perform noisy ventilation, the mechanical ventilator and the computer were utilized. Data were collected and analysed with the developed algorithm. The novel noisy ventilation system was found to be satisfactory in terms of its performance and its use in vivo showed that it can improve the respiratory system based on comparisons between estimated parameters and other outcomes such as blood gas, ultrasonography and electrical impedance tomography.
Mechanical Ventilator Control System Using Low-Cost Pressure Sensors
2021 International Conference on Computer Science, Information Technology, and Electrical Engineering (ICOMITEE), 2021
The increasingly active cases of people with the COVID-19 viruses have reached a very worrying level in most countries globally. The availability of ventilators in hospitals is one factor that increases the number of deaths in Indonesia. In this study, we present a control system on a mechanical ventilator using an inexpensive pressure sensor to control pressure, flow rate, and volume during the process of inspiration and expiration. The implemented method uses the venturi meter concept by comparing two air pressure sensors flowed by the Ambu bag. The control system on this ventilator uses a microcontroller and MPX5050DP sensor. The system tries to maintain the PEEP value of 5 cmH2O, and the feedback obtained ranges from 2.7-5.16 cmH2O. At the same time, the expected flowrate value of 55 L/min can be maintained at a value of 53.9-59.5 L/min. The tidal volume, which functions as a limiter for inspiration and expiration, is set at a value of 400 ml; the feedback given by the sensor varies between 416 ml-436 ml. Nevertheless, on the other hand, this system needs to be developed further because there are problems with sensor precision.
Periodic Modulation and Functional Demonstrations of Mechanically Operated Reciprocating Ventilator
International Journal for Research in Applied Science and Engineering Technology (IJRASET), 2022
During this period of COVID-19 pandemic, the lack of medical equipment (like ventilators) leads to complications arising in the medical field. A low-cost ventilator seems to be an alternative substitute to fill the lacking. This paper presents a numerical analysis for predicting the delivered parameters of a low-cost mechanical ventilator. Based on several manufactured mechanical ventilators, two proposed designs are investigated in this study. Fluid-structure interaction (FSI) analysis is used for solving any problems with the first design, and computational fluid dynamic (CFD) analysis with moving boundary is used for solving any issues with the second design. For this purpose, ANSYS Workbench platform is used to solve the set of equations. The results showed that the Ambu-bag-based mechanical ventilator exhibited difficulties in controlling ventilation variables, which certainly will cause serious health problems such as barotrauma. The mechanical ventilator based on piston-cylinder is more satisfactory with regards to delivered parameters to the patient. The ways to obtain pressure control mode (PCM) and volume control mode (VCM) are identified. Finally, the ventilator output is highly affected by inlet flow, length of the cylinder, and piston diameter.
Design and construction of a simplified, gas-driven, pressure-controlled emergency ventilator
African Journal of Emergency Medicine, 2021
Due to the COVID-19 crisis or any other mass casualty situation it might be necessary to give artificial ventilation to many affected patients. Contrarily, the worldwide availability of emergency ventilators is still a shortage, especially in developing countries. Methods: Modes of artificial ventilation were compared and the most safe, easy to use, and lung protecting principle was optimized to fit all requirements of both emergency ventilation and cost-effective mass production. Results: The presented research results describe a simplified device for a pressure-controlled ventilation which works without electricity according to a known principle. Just pressurized gas and a patient connection is required. The device enables the control of basic ventilator parameters such as peak inspiratory pressure, positive end-expiratory pressure and the ventilation frequency. Further, the device is semiadaptive to the patient's lung stiffness and automatically maintains minute volume through frequency adjustment. The machine can be manufactured by turning, milling and drilling and needs purchased components with costs less than 100 USD. A sterilization and thus a reuse is possible. Discussion: The presented development does not describe a ready-to-purchase ventilator, it rather outlines a refined working principle for emergency ventilation and its easiest methods of production with a minimum of requirements. The presented research aims on providing an open-source guideline for production of an emergency ventilator using worldwide available methods and thus should inspire local researchers to do a reverse engineering and eventually to put it into operation following country-specific regulations. For long-term ventilation exceeding emergency purposes, a monitoring of alarms for disconnection and violation of desired ventilator parameters should be established. The ventilator is limited to a fixed ratio between PIP and PEEP. Moreover, the ventilation frequency depends on two parameters, which needs some training. Nevertheless, the ventilator provides basic features to enable an emergency ventilation with minimal prerequisites. African relevance • Due to the COVID-19 crisis it might be necessary to give artificial ventilation to many affected patients • We describe a simplified gas-driven, fully mechanical, pressurecontrolled emergency ventilator with semiautomatic adjustment of PIP-controlled tidal volume and frequency • In comparison to existing ventilators, the devised ventilator can be self-manufactured and is hence independent from the availability of purchased ventilators.
www.repcomseet.org, 2023
Key medical equipment that is needed for effectively dealing with critical patients arising from COVID-19 infected patience is the Mechanical Ventilator. When the lungs are so damaged that a patient is not getting enough oxygen or exhaling carbon dioxide, the ventilator is used. A prior mechanical ventilator design did not incorporate mechanically adjustable inspiratory to expiratory ratio but through the use of electronic circuit boards and numerous central processing units (CPU) and sensors which often fails during use. In addition, most mechanical ventilators are either designed for adults or children; but not both. In Nigeria, electrical power supply to ensure uninterrupted power supply can be a challenge due to epileptic power supply from the utility companies. This paper presents the results of the development and prototyping of an electrically powered cam-actuated mechanical ventilator .mechanism for adjusting the inspiratory to the expiratory ratio (I/E) in the range 1:2 to 1:3. A breadth per minute of 12 to 25 was achieved after experimentation. This is expected to provide adequate breaths per minute (bpm) for the critical care of a COVID-19 patient. A careful design of the structural supports was able to interchangeably admit AMBU bags for pediatric use and adults. This adaptation eliminates the need for providing an independent mechanical ventilator system for adults and children. A modern sense approach and automatically activate other sources of electrical power to keep the mechanical ventilator running was explored for guaranteed performance during service.