Emergency Ventilation Research Articles

Methodical Approach Cleaning Emergency Ventilation Systems Emissions of Harmful Substances

In the event of an emergency situation at an industrial site with the release of ventilation systems into the atmosphere, a cleaning device is required, which should ensure that the excess of the explosive concentration in the surface layer of the atmosphere is above the normative value. Quantitatively, the release of explosives depends on the degree of depressurization of the system, its volume and pressure in it, the speed of the formation of the team to close the shut-off organs and its execution. The purification device of emergency emissions should have the properties of adequate counteraction to the specified accident factors for equipment that does not have internal self-protection. The emergency emissions are of a probabilistic nature, and therefore the structure of the treatment equipment and its operating conditions must differ from the structure and conditions when cleaning only technological emissions. The cleaning equipment must be able to neutralize large mass outlays of emissions in a short period of time, the operation of the equipment must be built on the principle of waiting for work, that is, in the automated mode, the time of entry into operation should be determined when hazardous concentrations of explosives in the room occur. The performance of the exhaust emergency ventilation and the moment of its activation are determined by the conditions for reaching the concentration of explosives in the room not exceeding 0,1 of the lower concentration limit of flame propagation in gasair explosive mixtures and ensuring dispersion of surface concentrations not higher than the established standard values, and for non-explosive mixtures – Only the second condition.

Pneuma: entrepreneurial science in the fight against the COVID-19 pandemic - a tale of industrialisation and international cooperation


 
 
 When the COVID-19 pandemic hits Portugal in early March 2020, medical doctors, engineers and researchers, with the encouragement of the Northern Region Health Administration, teamed up to develop and build, locally and in a short time, a ventilator that might eventually be used in extreme emergency situations in the hospitals of northern Portugal. This letter tells you the story of Pneuma, a low-cost emergency ventilator designed and built under harsh isolation constraints, that gave birth to derivative designs in Brazil and Morocco, has been industrialized with 200 units being produced and is now looking forward to the certification as a medical device that will possibly support a go-to-market launch. Open intellectual property (IP), multidisciplinarity teamwork, fast prototyping and product engineering have shortened to a few months an otherwise quite longer idea-to-product route, clearly demonstrating that when scientific and engineering knowledge hold hands great challenges can be successfully faced.
 
 

Thermal Potential Improvement of an Earth-Air Heat Exchanger (EAHE) by Employing Backfilling for Deep Underground Emergency Ventilation

Backfilling can enhance the thermal potential of an earth-air heat exchanger (EAHE) system, but traditional researches are hindered by the shallow buried/horizontal conditions or the limitation of air temperature concerned only. This present research fills in an important research gap by investigating the effect of backfilling on both heat and mass transfer of an EAHE system for deep underground emergency ventilation. The advanced numerical model is established and the agreements with field test data are satisfactory. The effect of the backfilling system has been investigated and the possible improvement has been identified. The results show that the effect of the backfilling technology is of almost equal significance to the EAHE system in some cases, and the upper limit of application depth for the backfilling technology is found. Successful deployment of the backfilling system will assist the emergency ventilation on its process towards energy-efficiency and thermal comfort, and the backfilling system can further improve the thermal performance up to 100% on the basis of the original system. However, backfilling is not an appropriate method for EAHE system under 400 m depth. And there is no need for the thermal conductivity of backfilling materials to be higher than 2.5 W/(m·K).

FMECA Assessment for Railway Safety-Critical Systems Investigating a New Risk Threshold Method

This paper develops a Failure Mode, Effects and Criticality Analysis (FMECA) for a heating, ventilation and air conditioning (HVAC) system in railway. HVAC is a safety critical system which must ensure emergency ventilation in case of fire and in case of loss of primary ventilation functions. A study of the HVAC's critical areas is mandatory to optimize its reliability and availability and consequently to guarantee a low operation and maintenance cost. The first part of the paper describes the FMECA which is performed and reported to highlight the main criticalities of the HVAC system under analysis. Secondly, the paper deals with the problem of the evaluation of a threshold risk value, which can distinguish negligible and critical failure modes. Literature barely considers the problem of an objective risk threshold estimation. Therefore, a new analytical method based on finite difference is introduced to find a univocal risk threshold value. The method is then tested on two Risk Priority Number datasets related to the same HVAC. The threshold obtained in both cases is a good tradeoff between the risk mitigation and the cost investment for the corrective actions required to mitigate the risk level. Finally, the threshold obtained with the proposed method is compared with the methods available in literature. The comparison shows that the proposed finite difference method is a well-structured technique, with a low computational cost. Furthermore, the proposed approach provides results in line with the literature, but it completely deletes the problem of subjectivity.

Emergency ventilator for COVID-19.

The COVID-19 pandemic disrupted the world in 2020 by spreading at unprecedented rates and causing tens of thousands of fatalities within a few months. The number of deaths dramatically increased in regions where the number of patients in need of hospital care exceeded the availability of care. Many COVID-19 patients experience Acute Respiratory Distress Syndrome (ARDS), a condition that can be treated with mechanical ventilation. In response to the need for mechanical ventilators, designed and tested an emergency ventilator (EV) that can control a patient’s peak inspiratory pressure (PIP) and breathing rate, while keeping a positive end expiratory pressure (PEEP). This article describes the rapid design, prototyping, and testing of the EV. The development process was enabled by rapid design iterations using additive manufacturing (AM). In the initial design phase, iterations between design, AM, and testing enabled a working prototype within one week. The designs of the 16 different components of the ventilator were locked by additively manufacturing and testing a total of 283 parts having parametrically varied dimensions. In the second stage, AM was used to produce 75 functional prototypes to support engineering evaluation and animal testing. The devices were tested over more than two million cycles. We also developed an electronic monitoring system and with automatic alarm to provide for safe operation, along with training materials and user guides. The final designs are available online under a free license. The designs have been transferred to more than 70 organizations in 15 countries. This project demonstrates the potential for ultra-fast product design, engineering, and testing of medical devices needed for COVID-19 emergency response.

Use of capnography to verify emergency ventilator sharing in the COVID-19 era

Exacerbation of COVID-19 pandemic may lead to acute shortage of ventilators, which may require shared use of ventilator as a lifesaving concept. Two model lungs were ventilated with one ventilator to i) test the adequacy of individual tidal volumes via capnography, ii) assess cross-breathing between lungs, and iii) offer a simulation-based algorithm for ensuring equal tidal volumes. Ventilation asymmetry was induced by placing rubber band around one model lung, and the uneven distribution of tidal volumes (VT) was counterbalanced by elevating airflow resistance (HR) contralaterally. VT, end-tidal CO2 concentration (ETCO2), and peak inspiratory pressure (Ppi) were measured. Unilateral LC reduced VT and elevated ETCO2 on the affected side. Under HR, VT and ETCO2 were re-equilibrated. In conclusion, capnography serves as simple, bedside method for controlling the adequacy of split ventilation in each patient. No collateral gas flow was observed between the two lungs with different time constants. Ventilator sharing may play a role in emergency situations.

Emergency evacuation risk assessment and mitigation strategy for a toxic gas leak in an underground space: The case of a subway station in Guangzhou, China

In emergency system design, evacuating people from dangerous buildings has always been a significant yet challenging undertaking. This paper combines evacuation demand analysis with a toxic gas dispersion process to create an underground space risk assessment model for toxic gas leaks. The emergency evacuation capacity of a subway transfer station in Guangzhou has been evaluated and optimized based on computational fluid dynamics (CFD) and agent-based simulation. A strategy is proposed in which the subway ventilation system in the underground space is utilized to mitigate evacuation risks during gas leaks. The influence of the ventilation system on the gas diffusion process under different working conditions during simulations of toxic gas diffusion is also analyzed. A comparative analysis is conducted to discuss whether to adopt the ventilation system. Then, the effectiveness of the risk methods when the ventilation system is utilized in different working conditions is also verified. An empirical model of the impacts of the number of evacuees and individual risk perception levels on the evacuation risk has been obtained. Results indicate that the new risk assessment and risk mitigation methods are effective and can help guide the emergency evacuation and ventilation system design for underground buildings.

Design of a Multi-Control Objective Rescue Mechanical Ventilation System (Linshomator).

In recent years, the need for a low-cost emergency ventilation system has increased unprecedentedly. Mechanical ventilation systems are widely used to cater to sudden oxygen demands, low breathing rates, and critical conditions during bradycardia and tachycardia. In this research, a new design of mechanical ventilation system synced with the tidal volume requirements of the patient using a piezoelectric belt has been proposed. The device proposed has various modes of ventilation—ACV (assisted controlled ventilation), SIMV (synchronized intermittent mandatory ventilation), and NIV (non-invasive ventilation), depending on the patient's requirements. A digital interface or user-friendly software has also been developed to help medical professionals easily monitor a patient's medical conditions. Finally, the automation that controls the ventilation mechanism of the device has been tested and validated with a conventional ventilator, and it has been found that the accuracy of the device in terms of delivering the exact quantity of air into the patient according to his requirements has been improved significantly. Further, the comparative study of the experimental data indicated that 5–10% error in detecting inhale and exhale attempt of a patient was detected with the conventional ventilator.

Design and construction of a simplified, gas-driven, pressure-controlled emergency ventilator.

IntroductionDue 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.MethodsModes 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.ResultsThe 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.DiscussionThe 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.

Q‐VENT—A novel device for emergency ventilation of the lungs in patients with respiratory failure due to diseases such as COVID‐19

AbstractSince the end of 2019, a novel coronavirus (SARS‐CoV‐2) causing pneumonia, often progressing to rapid deterioration with acute respiratory distress syndrome (ARDS) requiring advanced life support, has been spreading worldwide. The humanitarian crisis we are currently witnessing across the globe is threatening access to artificial ventilation of the lungs (AVL) for patients with respiratory failure. Q‐vent is a multi‐way air valve system with filters and heater/humidifier module produced by 3D printer from a new composite material based on Phloxine B, Saponite and Polylactic acid that prevents the formation of bacterial biofilms. This automated device, which can be fitted with commercially available Ambu® Breathing Bags or similar, provides a high degree of controllability along with one‐box complexity. A built‐in cough sensor warns of patient's awakening. In the case of power failure, Q‐vent switches to battery reserve. The developed device was tested on an intubated model (Gaumard® Scientific ‐ UNI®) corresponding to a patient (80 kg) with lung compliance 50 ml/cm H2O to simulate ARDS for 24 hours. The inspiration‐to‐expiration (I:E) ratio, tidal volume set to 8 ml/kg PBW (L‐type pneumonia) and 6 ml/kg PBW (H‐type Pneumonia), and frequency of inspiration were adjusted to test Q‐Vent operation at a range of different conditions. All functions performed reliably throughout the testing procedure. Q‐Vent successfully passed the Rapidly Manufactured Ventilator System (RMVS001) validation issued by MHRA and is awaiting clinical trials to determine its value in overcoming crises caused by the lack of conventional AVL.

Open Innovation in Times of Covid-19: The case of Project OxyGEN

In the face of the health crisis unleashed by Covid-19, experts worldwide took on the challenge of designing a low-cost emergency ventilator that could be assembled quickly. This study analizes the successful case of the Project OxyGEN, led by the Barcelona-based design firm Protofy, which created an industrial-class emergency ventilator and obtained approval from the Spanish Ministry of Health (AEMPS) for use on patients. The project received scientific support from a local Research Hospital, and SEAT, a Volkswagen subsidiary, collaborated in the OxyGEN ventilators’ mass-production. This open-hardware project sprung into action teams in more than 32 countries involved in the collaborative design process, adopted or made an iteration of the technology. These teams collaborated with suppliers, consultants, universities, and research institutes to drive this innovation forward. The case highlights the Open Innovation approach, inter-organisational relationships between firms of different sectors with research institutions, and innovation communities.

Jet fans efficiency in tunnel emergency situations

Tunnel construction has become an important and growing activity. Tunnelling is an important part of transport infrastructure and is a part of the sustainable development of the country. The tunnel ventilation during construction and operation is part of the whole design procedure. Although ventilation might be performed with different approaches, longitudinal ventilation with jet fans is most often employed. The efficiency of such devices depends on several factors – design parameters, location in the tunnel, interaction with main current. The last one is crucial in emergency situations, especially during fires when both temperature and density of main current change. One important point in normal and emergency ventilation design is the downwind influence of jet fans. This paper presents a longitudinal scheme with jet fans. Based on energy and mass conservation, the interaction between the jet fan and the main current is considered, leading to expressions for areas of impact. Several models for fire temperature distribution downstream are presented, outcomes are compared and suggestions for use are made. Additionally, jet fan efficiency coefficients are adjusted due to modelling results.

Design and performance testing of a novel emergency ventilator for in-hospital use.

BackgroundThe rapidly evolving COVID-19 pandemic has led to increased use of critical care resources, particularly mechanical ventilators. Amidst growing concerns that the health care system could face a shortage of ventilators in the future, there is a need for an affordable, simple, easy to use, emergency stockpile ventilator.MethodsOur team of engineers and clinicians designed and tested an emergency ventilator that uses a single limb portable ventilator circuit. The circuit is controlled by a pneumatic signal with electronic microcontroller input, using air and oxygen sources found in standard patient rooms. Ventilator performance was assessed using an IngMar ASL 5000 breathing simulator, and it was compared with a commercially available mechanical ventilator.ResultsThe emergency ventilator provides volume control mode, intermittent mandatory ventilation and continuous positive airway pressure. It can generate tidal volumes between 300 and 800 mL with <10% error, with pressure, volume, and waveforms substantially equivalent to existing commercial ventilators.ConclusionsWe describe a cost effective, safe, and easy to use ventilator that can be rapidly manufactured to address ventilator shortages in a pandemic setting. It meets basic clinical needs and can be provided for emergency use in cases requiring mechanical ventilation because of complications due to respiratory failure from infectious diseases.

Study on the optimal operation mode of ventilation system during metro double-island platform fire

Large metro transfer stations have been widely constructed in China, among which the double-island station faces the serious fire safety issues owing to its large passenger flow. In this paper, simulation cases were carried out to investigate the effectiveness of different ventilation modes by jointly operating tunnel ventilation fan (TVF) and platform screen doors (PSD) under two typical fire scenarios in the platform. The numerical model was established by Fire Dynamics Simulator software and verified via reduced-scale model experiments. The results indicate that the TVF mode of supplying at the end near fire and exhausting at the other end is superior to that of exhausting at both ends. Besides, activating more PSD and TVF on the both sides of platform will restrict smoke in one end to the greater extent. During a fire in the middle of the platform, opening all PSD near tunnel-2 and TVF in tunnel-2 and tunnel-3 is the most appropriate mode. While during a fire at the left end of the platform, activating all PSD and TVF on both sides is the optimal operation mode. The conclusions can provide guidance for smoke control design and on-site emergency ventilation operation in double-island platform fire.

Study on emergency ventilation mode for multisource fires in a typical interchange subway station

The fire protection design in a large-scale interchange station is always a great challenge. In this paper, a series of numerical simulations were conducted to investigate the performance of emergency ventilation modes for three potential multisource fire scenarios. The parameters that influence passengers’ evacuation were analyzed. The results demonstrated that unreasonable co-operation ventilation mode enhances the smoke propagation in other lines. The interaction of ventilation modes in different lines must be considered in practice. When the multisource fires occur on the same floor of both lines, the most effective scheme is to adopt the same ventilation mode in each line. When the multisource fires occur on different floors of both lines, it is difficult to maintain a balance of the exhaust capability in each line. The optimal ventilation modes were finally proposed for three fire scenarios based on the smoke discharge capability in the whole station.

Main criteria for explosion-fire hazards of biofuel production

Problem statement. A significant advantage of bioethanol production is the use of renewable energy sources. Since July 2021, gasoline produced and sold in Ukraine should consist of 5 % bioethanol. In the production of biofuels in Europe, most deaths occur due to underestimation of the possibility of emergency situations. Fire and explosion safety of enterprises is one of the most important areas in protecting people and the environment from serious consequences. To carry out preventive measures for fire and explosion safety, it is necessary to determine the main criteria for the explosion and fire hazard of bioethanol production at each enterprise.Purpose. To determine excess explosion pressure for bioethanol vapor and zone size, limiting the range of concentrations exceeding the lower concentration limit of flame propagation. Conclusions. Based on the calculation results, the values of the criteria for explosive and fire hazard for bioethanol, obtained at modernized sugar factories, are established. The size of the zone (Rnkmp), which limits the range of concentrations exceeding the lower concentration limit of flame propagation (Snkmp), is 7,8 m.The explosion overpressure for ethanol vapor is 14,37 kPa. In order to clearly display the fire hazard and conduct fire prevention in the production of bioethanol, it is necessary to develop fire-technical maps. The premises for bioethanol production should be provided with natural and mechanical emergency ventilation, mechanized and automated as much as possible, equipped with automatic fire extinguishing means and automatic fire alarms.

GlasVent-The Rapidly Deployable Emergency Ventilator.

As a result of the novel Coronavirus disease (COVID‐19) outbreak, a surge is witnessed in the demand for mechanical ventilators needed for treating affected patients. With the rapidly virus spreading around the globe, the shortage of ventilators becomes a global challenge and numerus efforts are followed. While industry mobilizes toward producing medical grade equipment, a number of low‐cost and less complex emergency ventilators have been developed, mainly through academic and open‐source channels, with a hope to meet any temporary needs gap until medical grade ventilator provision becomes sufficient. Herein, the design and implementation of one such emergency ventilator called GlasVent is presented, which an automated version of manual resuscitator device, commonly known as big valve mask or artificial manual breathing unit bag and widely used prior to initiating the mechanical ventilation. GlasVent uses 3D printed mechanical parts, widely available materials and off‐the‐shelf electronic and sensing devices which can be fast assembled. Furthermore, it requires minimal training and can be operated manually by hands or legs, thus meeting the emergency requirements even in the low‐resource settings or regions with less developed healthcare systems. Post‐COVID‐19, such ventilators can potentially find use in clinical care of a wider variety of patients with injury, pulmonary noncommunicable diseases, and severe asthma etc.

Low-Complexity System and Algorithm for an Emergency Ventilator Sensor and Alarm.

In response to anticipated shortages of ventilators caused by the COVID-19 pandemic, many organizations have designed low-cost emergency ventilators. Many of these devices are pressure-cycled pneumatic ventilators, which are easy to produce but often do not include the sensing or alarm features found on commercial ventilators. This work reports a low-cost, easy-to-produce electronic sensor and alarm system for pressure-cycled ventilators that estimates clinically useful metrics such as pressure and respiratory rate and sounds an alarm when the ventilator malfunctions. A low-complexity signal processing algorithm uses a pair of nonlinear recursive envelope trackers to monitor the signal from an electronic pressure sensor connected to the patient airway. The algorithm, inspired by those used in hearing aids, requires little memory and performs only a few calculations on each sample so that it can run on nearly any microcontroller.

A Gas-Powered, Patient-Responsive Automatic Resuscitator for Use in Acute Respiratory Failure: A Bench and Experimental Study.

During the COVID-19 pandemic, a need for innovative, inexpensive, and simple ventilator devices for mass use has emerged. The Oxylator (CPR Medical Devices, Markham, Ontario, Canada) is an FDA-approved, fist-size, portable ventilation device developed for out-of-hospital emergency ventilation. It has not been tested in conditions of severe lung injury or with added PEEP. We aimed to assess the performance and reliability of the device in simulated and experimental conditions of severe lung injury, and to derive monitoring methods to allow the delivery of safe, individualized ventilation during situations of surge. We bench-tested the functioning of the device with an added PEEP valve extensively, mimicking adult patients with various respiratory mechanics during controlled ventilation, spontaneous breathing, and prolonged unstable conditions where mechanics or breathing effort was changed at every breath. The device was further tested on a porcine model (4 animals) after inducing lung injury, and these results were compared with conventional ventilation modes. The device was stable and predictable, delivering a constant flow (30 L/min) and cycling automatically at the inspiratory pressure set (minimum of 20 cm H2O) above auto-PEEP. Changes in respiratory mechanics manifested as changes in respiratory timing, allowing prediction of tidal volumes from breathing frequency. Simulating lung injury resulted in relatively low tidal volumes (330 mL with compliance of 20 mL/cm H2O). In the porcine model, arterial oxygenation, CO2, and pH were comparable to conventional modes of ventilation. The Oxylator is a simple device that delivered stable ventilation with tidal volumes within a clinically acceptable range in bench and porcine lung models with low compliance. External monitoring of respiratory timing is advisable, allowing tidal volume estimation and recognition of changes in respiratory mechanics. The device can be an efficient, low-cost, and practical rescue solution for providing short-term ventilatory support as a temporary bridge, but it requires a caregiver at the bedside.

Living on Borrowed Breath: Respiratory Distress, Social Breathing, and the Vital Movement of Ventilators.

Based on ethnographic research in a public hospital trauma intensive care unit in Mumbai, India, this article formulates the concept of “social breathing” to analyze how breath is central to values of life at the edges of death. Case studies of emergency resuscitation, intubation, and ventilation each illustrate breathing's sociality, as people and machines move air both materially and immaterially. Amid the hospital's rationing of life support technologies, forms of life that seem to be self‐regulated are better understood as relational movements of breath. Social breathing stands to reshape our understanding of the biopolitics of intensive care by drawing attention to uncertain techniques of the body. These techniques move at the hinge between person and environment, self and other, public and private health care systems, and medicine and machine. Life's valuation at this hinge takes shape through breath moving against its limits. Ultimately, the article argues that it is crucial to understand how ventilators mediate the edges of life and death by tracing the circulations of life support as the movements of life itself. As patients, families, and hospital workers struggle to make and manage breath, we might better grapple with the social relations that emerge as life support shapes life.