Patient–Ventilator Interaction Testing Using the Electromechanical Lung Simulator xPULM™ during V/A-C and PSV Ventilation Mode (original) (raw)
Related papers
Computer-controlled mechanical simulation of the artificially ventilated human respiratory system
IEEE Transactions on Biomedical Engineering, 2003
A mechanical lung simulator can be used to simulate specific lung pathologies, to test lung-function equipment, and in instruction. A new approach to mechanical simulation of lung behavior is introduced that uses a computer-controlled active mechatronic system. The main advantage of this approach is that the static and dynamic properties of the simulator can easily be adjusted via the control software. A nonlinear single-compartment mathematical model of the artificially ventilated respiratory system has been derived and incorporated into the simulator control system. This model can capture both the static and dynamic compliance of the respiratory system as well as nonlinear flow-resistance properties. Parameters in this model can be estimated by using data from artificially ventilated patients. It is shown that the simulation model fits patient data well. This mathematical model of the respiratory system was then matched to a model of the available physical equipment (the simulator, actuators, and the interface electronics) in order to obtain the desired lung behavior. A significant time delay in the piston motion control loop has been identified, which can potentially cause oscillations or even instability for high compliance values. Therefore, a feedback controller based on the Smith-predictor scheme was developed to control the piston motion. The control system, implemented on a personal computer, also includes a user-friendly interface to allow easy parameter setting.
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.
Revista Facultad de Ingeniería Universidad de Antioquia
The respiratory mechanics assessment in patients with mechanical ventilation allows to adjust the treatment in intensive care units related to the ventilatory mode and parameters of mechanical ventilator settings. However, to estimate the compliance and respiratory resistance in spontaneous ventilation is only possible with obstructive maneuvers or invasive techniques. One of the most important limitations to develop new techniques for respiratory mechanics estimation is the non-stationary characteristic of the system and the variability of parameters according to the variability of the breathing pattern. The aim of this article is to present and evaluate a device that allows artificially modify the thoracic compliance of a healthy subject, which will make possible to register in the future a useful database for the development of techniques for estimating ventilatory mechanics. The device was formed by a cuirass, a pump and a controller that allows to vary the pressure inside the cuirass, which was placed in the chest and abdomen of the volunteers to change compliance in a controlled manner. 5 volunteers participated in the performance test of the device, achieving percentage changes of 34.5 ± 9.4% respecting their resting value for a pressure of 10 cmH 2 O and changes of 46.8 ± 5.7% for the maximum pressure of 20 cmH 2 O. It was possible to design a device that allowed to artificially modify thoracic compliance in a comparable way for any healthy subject.
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...
Patient Emulator: A Tool for Testing Mechanical Ventilation Therapies
Several modes of mechanical ventilation are clinically available. The differences among them in terms of efficacy and patient outcomes are not clear yet. Testing and comparison of mechanical ventilation modes via human or animal trials is a very challenging and costly process. In this paper, we present the patient emulator (PE), a novel system that can be used as a platform for in-silico testing of mechanical ventilation therapies. The system is based on a large-scale integrated mathematical model of the human cardiopulmonary system interfaced with a physical ventilator via a controlled piston-cylinder actuator. The performance of the proposed PE is demonstrated by simulating a realistic pressure support ventilation step protocol. The PE-simulated patient's response is then compared against averaged data from 33 human subjects. The agreement between the simulated data and their experimental counterparts shows the potential of the proposed PE to be used as a substitute for or in addition to conventional animal and human trials.
Realistic human muscle pressure for driving a mechanical lung
EPJ Nonlinear Biomedical Physics, 2014
Background: An important issue in noninvasive mechanical ventilation consists in understanding the origins of patient-ventilator asynchrony for reducing their incidence by adjusting ventilator settings to the intrinsic ventilatory dynamics of each patient. One of the possible ways for doing this is to evaluate the performances of the domiciliary mechanical ventilators using a test bench. Such a procedure requires to model the evolution of the pressure imposed by respiratory muscles, but for which there is no standard recommendations.
We aimed to validate the mathematical validity and accuracy of the respiratory components of the Nottingham Physiology Simulator (NPS), a computer simulation of physiological models. Subsequently, we aimed to assess the accuracy of the NPS in predicting the effects of a change in mechanical ventilation on patient arterial blood-gas tensions. The NPS was supplied with the following measured or calculated values from patients receiving intensive therapy: pulmonary shunt and physiological deadspace fractions, oxygen consumption, respiratory quotient, cardiac output, inspired oxygen fraction, expired minute volume, haemoglobin concentration, temperature and arterial base excess. Values calculated by the NPS for arterial oxygen tension and saturation ( 2 O a P and 2 O a ), S mixed venous oxygen tension and saturation 2 O V (P and 2 O V ), S arterial and mixed venous carbon dioxide tension 2 CO ( a P and 2 CO V )