ABSTRACT
We recently read an interesting study which demonstrated that self-inflating resuscitation bag (SIRB) lacking expiratory valve has unreliable performance in oxygen delivery during spontaneous breathing mimicked by mechanical lung simulator. It was postulated that the absence of an expiratory valve and the resulting air entrainment via the exhaust port accounts for the poor oxygen delivery performance. The current disposable SIRB in-use in our institutions (Med-Rescuer Disposable BVM Resuscitator 4000, BLS Systems Limited, ON, Canada) has a duckbill valve but no expiratory valve. Safety concerns regarding its oxygen delivery performance during spontaneous breathing were raised, as this SIRB was commonly used to preoxygenate critically ill patient with potentially transmissible respiratory infection (e.g. COVID-19) before tracheal intubation. We therefore performed an experiment on this SIRB using one of us as a healthy volunteer. Our small experiment demonstrated that air entrainment could occur via the exhaust port and affect oxygen delivery performance. Our experiment also demonstrated that attaching a positive end-expiratory pressure (PEEP) valve to the exhaust port improves the oxygen delivery performance. The findings of this experiment were sent to the relevant department of our institutions for safety consideration. © The Author(s) 2022.
ABSTRACT
Background: Preoxygenation using a bag valve mask (BVM) with a filter is recommended to reduce the risk of viral transmission. Preoxygenation in hypoxaemic patients may require a positive end-expiratory pressure (PEEP) valve. Applying a filter to a BVM with or without a PEEP valve can increase resistance and work of breathing. Objective(s): To evaluate the efficacy of proximal oxygen added to BVM with mechanical filter in healthy volunteers. Material(s) and Method(s): The present study was a crossover trial that randomized 48 volunteers to receive four preoxygenation techniques: BVM with a filter as group F, BVM with a filter and proximal oxygen as group FO, BVM with a filter and PEEP valve as group FP, and BVM with a filter, PEEP valve, and proximal oxygen as group FPO. Fraction of expired oxygen (FEO2) and continuous positive airway pressure (CPAP) were measured. Comfort was assessed using a numerical rating scale (NRS). The primary outcome was FEO2 at five minutes. Result(s): Data from 46 volunteers were analyzed. Adding oxygen proximal to the filter in the FO group increased FEO2 at five minutes by 7.07% (95% CI 4.87 to 9.26) and decreased the time to reach FEO2 90% by 301.74 seconds (95% CI 282.82 to 320.66) compared with the times in group F. Similarly, supplemental proximal oxygen including a PEEP valve increased FEO2 at five minutes by 6.07% (95% CI 3.87 to 8.26) and decreased the time to reach FEO2 90% by 242.13 seconds (95% CI 223.21 to 261.05). CPAP was 2.27, 3.61, 11.65, and 13.14 mmHg in group F, FO, FP, and FPO, respectively. The NRS score was 6.51 and 6.07 in groups F and FO, and 3.15 and 3.70 in groups FP and FPO, respectively. Conclusion(s): Adding proximal oxygen to a BVM with a filter improved the efficacy of preoxygenation. Copyright © 2023 JOURNAL OF THE MEDICAL ASSOCIATION OF THAILAND.
ABSTRACT
Even before the COVID-19 pandemic, most hospitals in the Philippines, especially the rural and small hospitals, lacked respirators such as medical ventilators. With only a few thousand of these devices, the lack of emergency ventilators is a crucial problem in battling the COVID-19 pandemic in the Philippines. Hence, the study aimed to design an economical and portable mechanical emergency ventilator for respiratory support. It was achieved by effectively calibrating, automating, and controlling the working principle of BVM. Particularly, a CAM arm was designed to allow constant, smooth, and repeatable compression on the bag. Subsequently, driving the arm is a motor that was selected carefully according to the necessary motor torque and power calculations. Consequently, an effective close loop control system using a PID controller was implemented to control the motor position and speed. Although, the controller contains small inaccuracies that generate discrepancies in the volume measurement, and the pressure sensor records unusual readings due to breathing connection issues. The overall prototype confirms the minimum clinical specifications for a mechanical ventilator. As a result, the prototype has two ventilator modes, volume and assist control. It weighs 6.75 kg and has adimension of 385 × 270 × 235 mm. © 2022 IEEE.
ABSTRACT
Purpose In the COVID-19 outbreak periods, people's life has been deranged, leading to disrupt the world. Firstly, the number of deaths is growing and has the potential to surpass the highest level at any time. Secondly, the pandemic broke many countries' fortified lines of epidemic prevention and gave people a more honest view of its seriousness. Finally, the pandemic has an impact on life, and the economy led to a shortage in medical, including a lack of clinicians, facilities and medical equipment. One of those, a simple ventilator is a necessary piece of medical equipment since it might be useful for a COVID-19 patient's treatment. In some cases, the COVID-19 patients require to be treated by modern ventilators to reduce lung damage. Therefore, the addition of simple ventilators is a necessity to relieve high work pressure on medical bureaucracies. Some low-income countries aim to build a simple ventilator for primary care and palliative care using locally accessible and low-cost components. One of the simple principles for producing airflow is to squeeze an artificial manual breathing unit (AMBU) iterative with grippers, which imitates the motion of human fingers. Unfortunately, the squeezing angle of grippers is not proportional to the exhaust air volume from the AMBU bag. This paper aims to model the AMBU bag by a mathematical equation that enables to implement on a simple controller to operate a bag-valve-mask (BVM) ventilator with high accuracy performance. Design/methodology/approach This paper provides a curvature function to estimate the air volume exhausting from the AMBU bag. Since the determination of the curvature function is sophisticated, the coefficients of the curvature function are approximated by a quadratic function through the experimental identification method. To obtain the high accuracy performance, a linear regression model and a least square method are employed to investigate the characteristic of the BVM ventilator's grippers angle with respect to the airflow volume produced by the AMBU bag. Findings This paper investigates the correlation between the exhausting airflow of the AMBU bag and the grippers angle of the BVM ventilator. Originality/value The experimental results validated that the regression model of the characteristic of the exhausting airflow of the AMBU bag with respect to the grippers' angle has been fitted with a coefficient over 98% within the range of 350-750 ml.
ABSTRACT
Development of a working prototype of an affordable mechanical ventilator is discussed in this paper. The device uses a bag valve mask and two pushing handles to compress it and force-feed the air into the patient's lungs. A stepper motor along with a reduction mechanism made up of belt drives and spur gears are used to drive the pushing handles. A flow sensor is used to measure the airflow enabling closed-loop control of the air volume supplied to patients based on their lung parameters, i.e., compliance, resistance. Two absolute barometric pressure sensors are used to measure and report the gauge pressure and trigger the alarm buzzer in the case of high respiratory pressures. The prototype is tested using a test lung and the test lung's parameters are estimated using the flow and pressure data logged by the onboard microcontroller. Estimated compliance is very close to the test lung's reported compliance but the resistance is higher and the reason seemed to be the tube used to connect the prototype to the test lung. © 2022 IEEE.
ABSTRACT
Ventilator has become an intensively important part of medicalhealthcare, especially in this widespread pandemic of COVID-19. The most popular one is an Ambu Bag with a bag valve mask (BVM). This ventilator, however, requires a manual resuscitator to operate its function with a limited air volume inside the bag. During the operation, moreover, it causes the noisy sound due to its mechanism as well. The alternative is using Non-Ambu Bag ventilator. This optional ventilator can regulate using user's smartphone to command the operation of ventilator with configurable quantity and rate of volume and flow. © 2021 IEEE.
ABSTRACT
This study is focussed on the design and modelling of a low-cost ventilator design that can be developed using locally sourced materials in Nigeria. This is meant to aid in the country's fight against the current COVID-19 pandemic where there is a shortage of ventilators. The ventilator design in this research was based on a mechanical AMBU bag compression principle using the volume-control ventilation (VCV) mode, which will eliminate the need for manual compression, which can be tedious and uncontrolled. The design is powered by an electric motor with variable speed and tidal volume control. It also features an alarm that alerts medical personnel of unstable conditions in the system parameters. This prototype shows that the mechanical compression systems is a viable and more economical option that provides the essential features required in the standard existing technologies.
ABSTRACT
Mass casualty incidents such as those that are being experienced during the novel coronavirus disease (COVID-19) pandemic can overwhelm local healthcare systems, where the number of casualties exceeds local resources and capabilities in a short period of time. The influx of patients with lung function deterioration as a result of COVID-19 has strained traditional ventilator supplies. To bridge the gap during ventilator shortages and to help clinicians triage patients, manual resuscitator devices can be used to deliver respirations to a patient requiring breathing support. Bag-valve mask (BVM) devices are ubiquitous in ambulances and healthcare environments, however require a medical professional to be present and constantly applying compression to provide the patient with respirations. We developed an automated manual resuscitator-based emergency ventilator-alternative (AMREV) that provides automated compressions of a BVM in a repetitive manner and is broadly compatible with commercially-available BVM devices approximately 5 inches (128 mm) in diameter. The AMREV device relieves the medical professional from providing manual breathing support and allows for hands-free operation of the BVM. The AMREV supports the following treatment parameters: 1) adjustable tidal volume (V T ), 2) positive end-expiratory pressure (PEEP) (intrinsic and/or external), 3) 1:1 inspiratory: expiratory ratio, and 4) a controllable respiratory rate between 10-30 breaths per minute. The relationship between the inherent resistance and compliance of the lung and the delivered breaths was assessed for the AMREV device. Adjustable V T of 110-700 ml was achieved within the range of simulated lung states. A linear increase in mean airway pressure (P aw ), from 10-40 cmH2O was observed, as the resistance and compliance on the lung model moved from normal to severe simulated disease states. The AMREV functioned continuously for seven days with less than 3.2% variation in delivered V T and P aw . Additionally, the AMREV device was compatible with seven commercially-available BVM setups and delivered consistent V T and P aw within 10% between models. This automated BVM-based emergency-use resuscitator can provide consistent positive pressure, volume-controlled ventilation over an extended duration when a traditional ventilator is not available. True ventilator shortages may lead to manual resuscitators devices such as the AMREV being the only option for some healthcare systems during the COVID-19 pandemic.
ABSTRACT
The pandemic of COVID 19 has taken a massive toll of lives since its outbreak. Throughout the world with a large number of people being affected by covid 19, the need for the ventilators has risen. However, there is disproportionate ratio of demand versus supply of ventilators due to the menace caused by Covid 19 which has become unmanageable. This paper describes the design of the low cost portable mechanical bag valve mask compressor which could serve as a preliminary ventilator for the patients needing ventilator support in COVID 19. This prototype ventilator delivers breaths by compressing a conventional bag-valve mask (BVM) with a motor, eliminating the need for a human operator for the BVM. It is driven by a wind shield wiper electric motor powered by a 12 V battery. Additionally it can be used to deliver oxygen through either Laryngeal mask or compact face masks or nasopharyngeal airways where intubation is awaited in early breathlessness. Future additions for our prototype ventilator will include a controllable inspiration to expiration time ratio, a pressure relief valve, PEEP capabilities and an LCD screen. With a prototyping cost of only $150, the concept of BVM compressor is a low-cost, low-power portable ventilator technology that will provide essential ventilator features at a fraction of the cost of existing technology.
ABSTRACT
We present a low-cost clinically viable ventilator design, AmbuBox, using a controllable pneumatic enclosure and standard manual resuscitators that are readily available (AmbuBag), which can be rapidly deployed during pandemic and mass-casualty events with a minimal set of components to manufacture and assemble. The AmbuBox is designed to address the existing challenges presented in the existing low-cost ventilator designs by offering an easy-to-install and simple-to-operate apparatus while maintaining a long lifespan with high-precision flow control. As an outcome, a mass-producible prototype of the AmbuBox has been devised, characterized, and validated in a bench test setup using a lung simulator. This prototype will be further investigated through clinical testing. Given the potentially urgent need for inexpensive and rapidly deployable ventilators globally, the overall design, operational principle, and device characterization of the AmbuBox system have been described in detail with open access online. Moreover, the fabrication and assembly methods have been incorporated to enable short-term producibility by a generic local manufacturing facility. In addition, a full list of all components used in the AmbuBox has been included to reflect its low-cost nature.