scholarly journals Design and Analysis of a Mechanical Ventilation System Based on Cams

2020 ◽  
Author(s):  
Jesús Calderón ◽  
Carlos Rincón ◽  
Bray Agreda ◽  
Juan José Jiménez
Keyword(s):  
Mathematical Model ◽  
Mechanical Ventilation ◽  
Low Cost ◽  
Ventilation System ◽  
External Solution ◽  
Rotation Frequency ◽  
Medical Centers ◽  
Compression Mechanism ◽  
Available Technology ◽  
Over Time

A mechanical ventilation system is a big support for breathing complications, in which an external solution is quite necessary to keep oxygen compensation in the patients. Its knowledge is well widespread and different equipment has been developed. However, they are very expensive and their quantity in medical centers is not sufficient, especially in Peru. Hence, it has been required to develop new methods to provide oxygen by a low cost equipment; Protofy, a research group from Spain, designed one of the first low cost mechanical ventilation systems which was medically validated by its government. In this sense, a redesign of the mechanical ventilation system was carried out according to the local requirements and available technology, a different airbag resuscitator with different properties and geometry, but maintaining its working concept based on a cam compression mechanism. Sensors and a display were added to improve the performance with a control algorithm for the rotation frequency and to show the ventilation curves over time to the medical staff. It was necessary to develop a mathematical model to relate the behavior between ventilation curves for a patient and physical variables of the design, especially in the epidemic COVID 19, that many countries are dealing with at the time research is being conducted. The mechanical ventilation system was redesigned, fabricated, and tested measuring its ventilation curves over time. Results indicate that this redesign provides a sturdy equipment able to work during a longer lifetime than the original. The replicability of the ventilation curves behavior is assured, while the mechanism dimensions are adapted for a particular airbag resuscitator. The mathematical model of the whole system can predict satisfactorily the ventilation curves over time and was used to provide the air pressure, volume, and flow as a function of the rotation angle measured by sensors.

scholarly journals Dynamic Characteristics of Mechanical Ventilation System of Double Lungs with Bi-Level Positive Airway Pressure Model

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Dongkai Shen ◽  
Qian Zhang ◽  
Yan Shi
Keyword(s):  
Mathematical Model ◽  
Mechanical Ventilation ◽  
Dynamic Characteristics ◽  
Airway Pressure ◽  
Life Support ◽  
Positive Airway Pressure ◽  
Coupling Effect ◽  
Ventilation System ◽  
System A ◽  
Set Up

In recent studies on the dynamic characteristics of ventilation system, it was considered that human had only one lung, and the coupling effect of double lungs on the air flow can not be illustrated, which has been in regard to be vital to life support of patients. In this article, to illustrate coupling effect of double lungs on flow dynamics of mechanical ventilation system, a mathematical model of a mechanical ventilation system, which consists of double lungs and a bi-level positive airway pressure (BIPAP) controlled ventilator, was proposed. To verify the mathematical model, a prototype of BIPAP system with a double-lung simulators and a BIPAP ventilator was set up for experimental study. Lastly, the study on the influences of key parameters of BIPAP system on dynamic characteristics was carried out. The study can be referred to in the development of research on BIPAP ventilation treatment and real respiratory diagnostics.

A RESPIRATORY MECHANICAL PARAMETERS ESTIMATION TECHNOLOGY BASED ON EXTENDED LEAST SQUARES

2016 ◽  
Vol 16 (03) ◽  
pp. 1650028 ◽  
Author(s):  
YAN SHI ◽  
JINGLONG NIU ◽  
MAOLIN CAI ◽  
WEIQING XU
Keyword(s):  
Mathematical Model ◽  
Mechanical Ventilation ◽  
Least Squares ◽  
Ventilation System ◽  
Estimation Method ◽  
Parameters Estimation ◽  
Noise Model ◽  
Estimation Methods ◽  
Estimation Accuracy ◽  
Mechanical Parameters

Respiratory mechanical parameters of ventilated patients are usually referred in the respiratory diagnosis and treatment. However, the effectiveness of the modern estimation methods is limited. To estimate the overall breathing resistance, overall respiratory compliance, and residual volume simultaneously, a new mathematical model of mechanical ventilation system was proposed. Furthermore, to improve the estimation accuracy, the noise model of mechanical ventilation system was taken into consideration. Based on the mathematical model, a respiratory mechanical parameters estimation method based on extended least squares (ELS) algorithm was derived. Finally, to test the respiratory mechanical parameters estimation method, it was studied experimentally and numerically, and it was approved that the proposed method is effective to estimate the three respiratory mechanical parameters simultaneously and precisely. The estimated values of the parameters can be adopted in the clinical practice. The study provides a new method to estimate respiratory mechanical parameters.

scholarly journals A Low-Cost Air Flow Sensor/Transducer for Medical Applications: Design and Experimental Characterization

2021 ◽  
Author(s):  
Jesús Calderón ◽  
Carlos Rincón ◽  
Bray Agreda ◽  
Sebastián Calero ◽  
Manuel Bornas ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Breathing Circuit ◽  
Low Cost ◽  
Air Flow ◽  
Ventilation System ◽  
Integrated Design ◽  
Electrical Signal ◽  
Flow Sensor ◽  
Mechanical Ventilators ◽  
Sensor Transducer

Mechanical ventilation systems, which are used for breathing support when a person is not able to do it by their own, requires a device for measuring the air flow to the patient in order to monitoring and a assure the magnitude establish by a medical staff. Flow sensors are the conventional devices used for the air flow measuring; however, there were not available in Peru, because of the international demand during COVID-19 pandemic. In this sense, a novel air flow sensor based on orifice plate and an intelligent transducer stage were developed as an integrated design. Advanced methodologies in simulations and experiments using specially designed equipment for this application were carried out. The obtained data was used for a mathematical characterization and dimensions validation of the integrated design. The device was tested in its real working conditions, it was implemented in a breathing circuit connected to a low-cost mechanical ventilation system based on cams. Results indicate that the designed air flow sensor/transducer is a low-cost complete medical device for mechanical ventilators able to provide satisfactorily all the ventilation parameters air flow, pressure and volume over time by measuring the air flow and calculating the others. Furthermore, this device provides directly a filtered equivalent electrical signal for a display or a computer.

scholarly journals Modelling and Simulation of Volume Controlled Mechanical Ventilation System

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yan Shi ◽  
Shuai Ren ◽  
Maolin Cai ◽  
Weiqing Xu
Keyword(s):  
Mathematical Model ◽  
Mechanical Ventilation ◽  
Respiratory System ◽  
Ventilation System ◽  
Delay System ◽  
Time Delay System ◽  
Typical Time ◽  
Controlled Mechanical Ventilation ◽  
The Mathematical Model ◽  
Volume Controlled

Volume controlled mechanical ventilation system is a typical time-delay system, which is applied to ventilate patients who cannot breathe adequately on their own. To illustrate the influences of key parameters of the ventilator on the dynamics of the ventilated respiratory system, this paper firstly derived a new mathematical model of the ventilation system; secondly, simulation and experimental results are compared to verify the mathematical model; lastly, the influences of key parameters of ventilator on the dynamics of the ventilated respiratory system are carried out. This study can be helpful in the VCV ventilation treatment and respiratory diagnostics.

scholarly journals Pressure Dynamic Characteristics of Pressure Controlled Ventilation System of a Lung Simulator

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Yan Shi ◽  
Shuai Ren ◽  
Maolin Cai ◽  
Weiqing Xu ◽  
Qiyou Deng
Keyword(s):  
Mathematical Model ◽  
Mechanical Ventilation ◽  
Dynamic Characteristics ◽  
Life Support ◽  
Human Lung ◽  
Ventilation System ◽  
Experimental Studies ◽  
Diagnostic Systems ◽  
Lung Simulator ◽  
Pressure Dynamics

Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototype mechanical ventilation system of a lung simulator was proposed for experimental study. Last, simulation and experimental studies on the air flow dynamic of the mechanical ventilation system were done, and then the pressure dynamic characteristics of the mechanical system were obtained. The study can be referred to in the pulmonary diagnostics, treatment, and design of various medical devices or diagnostic systems.

scholarly journals The Impact of Intervention-Related Risk Factors on the Risk of Ventilator-Associated Pneumonia Is High in a Neurosurgical Intensive Care Unit

2020 ◽  
Vol 41 (S1) ◽  
pp. s407-s409
Author(s):  
Ksenia Ershova ◽  
Oleg Khomenko ◽  
Olga Ershova ◽  
Ivan Savin ◽  
Natalia Kurdumova ◽  
...  
Keyword(s):  
Risk Factors ◽  
Mechanical Ventilation ◽  
Negative Slope ◽  
Infection Prevention And Control ◽  
Ventilator Associated Pneumonia ◽  
Related Factors ◽  
Icu Patients ◽  
The Impact ◽  
Adf Test ◽  
Over Time

Background: Ventilator-associated pneumonia (VAP) represents the highest burden among all healthcare-associated infections (HAIs), with a particularly high rate in patients in neurosurgical ICUs. Numerous VAP risk factors have been identified to provide a basis for preventive measures. However, the impact of individual factors on the risk of VAP is unclear. The goal of this study was to evaluate the dynamics of various VAP risk factors given the continuously declining prevalence of VAP in our neurosurgical ICU. Methods: This prospective cohort unit-based study included neurosurgical patients who stayed in the ICU >48 consecutive hours in 2011 through 2018. The infection prevention and control (IPC) program was implemented in 2010 and underwent changes to adopt best practices over time. We used a 2008 CDC definition for VAP. The dynamics of VAP risk factors was considered a time series and was checked for stationarity using theAugmented Dickey-Fuller test (ADF) test. The data were censored when a risk factor was present during and after VAP episodes. Results: In total, 2,957 ICU patients were included in the study, 476 of whom had VAP. Average annual prevalence of VAP decreased from 15.8 per 100 ICU patients in 2011 to 9.5 per 100 ICU patients in 2018 (Welch t test P value = 7.7e-16). The fitted linear model showed negative slope (Fig. 1). During a study period we observed substantial changes in some risk factors and no changes in others. Namely, we detected a decrease in the use of anxiolytics and antibiotics, decreased days on mechanical ventilation, and a lower rate of intestinal dysfunction, all of which were nonstationary processes with a declining trend (ADF testP > .05) (Fig. 2). However, there were no changes over time in such factors as average age, comorbidity index, level of consciousness, gender, and proportion of patients with brain trauma (Fig. 2). Conclusions: Our evidence-based IPC program was effective in lowering the prevalence of VAP and demonstrated which individual measures contributed to this improvement. By following the dynamics of known VAP risk factors over time, we found that their association with declining VAP prevalence varies significantly. Intervention-related factors (ie, use of antibiotics, anxiolytics and mechanical ventilation, and a rate of intestinal dysfunction) demonstrated significant reduction, and patient-related factors (ie, age, sex, comorbidity, etc) remained unchanged. Thus, according to the discriminative model, the intervention-related factors contributed more to the overall risk of VAP than did patient-related factors, and their reduction was associated with a decrease in VAP prevalence in our neurosurgical ICU.Funding: NoneDisclosures: None

scholarly journals Effect of Mechanical Ventilation on Accidental Hydrogen Releases—Large-Scale Experiments

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3008
Author(s):  
Agnieszka W. Lach ◽  
André V. Gaathaug
Keyword(s):  
Mechanical Ventilation ◽  
Mass Flow ◽  
Large Scale ◽  
Ventilation System ◽  
Hydrogen Gas ◽  
Forced Ventilation ◽  
British Standard ◽  
Confined Spaces ◽  
Series Of Experiments ◽  
Rate Limit

This paper presents a series of experiments on the effectiveness of existing mechanical ventilation systems during accidental hydrogen releases in confined spaces, such as underground garages. The purpose was to find the mass flow rate limit, hence the TPRD diameter limit, that will not require a change in the ventilation system. The experiments were performed in a 40 ft ISO container in Norway, and hydrogen gas was used in all experiments. The forced ventilation system was installed with a standard 315 mm diameter outlet. The ventilation parameters during the investigation were British Standard with 10 ACH and British Standard with 6 ACH. The hydrogen releases were obtained through 0.5 mm and 1 mm nozzles from different hydrogen reservoir pressures. Both types of mass flow, constant and blowdown, were included in the experimental matrix. The analysis of the hydrogen concentration of the created hydrogen cloud in the container shows the influence of the forced ventilation on hydrogen releases, together with TPRD diameter and reservoir pressure. The generated experimental data will be used to validate a CFD model in the next step.

Survival of Mycobacteria on Hepa Filter Material

1998 ◽  
Vol 3 (2) ◽  
pp. 65-78 ◽  
Author(s):  
Gwangpyo Ko ◽  
Harriet A. Burge ◽  
Michael Muilenberg ◽  
Stephen Rudnick ◽  
Melvin First
Keyword(s):  
High Efficiency ◽  
Ventilation System ◽  
Filter Material ◽  
Survival Curves ◽  
Mycobacterium Chelonae ◽  
Air Filters ◽  
Liquid Suspension ◽  
Static Conditions ◽  
Strain H37rv ◽  
Over Time

Mycobacterium tuberculosis (MTB) is transmitted through the air, and can be captured on ventilation air filters. People handling these filters may be exposed to infectious material. We studied the survival of strains of Mycobacterium on high efficiency particulate air (HEPA) filter material. We used a model ventilation system to evaluate survival over time of Mycobacterium chelonae and H37Ra (an avirulent stain of MTB) aerosolized and then captured on HEPA filter material. Survival curves for M. chelonae incubated at 55% and 75% RH under static conditions were not different with less than 4% survival at 24 hours. H37Ra was subjected to continuous airflow at the design airflow for the filter material following deposition on the HEPA filter material, and less than 0.1% of cells survived to 48 hours (RH not controlled). H37Ra was resistant to immobilized biocide (trimethoxysilylpropyl dimethyloctadecyl ammonium chloride) on HEPA filter material as well as the same biocide in solution. Finally, survival of H37Ra and virulent MTB strain (H37Rv) were not different following deposition onto HEPA filter material from liquid suspension and incubation under static conditions.

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