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Project Spotlight: OpenVent-Bristol

OpenVent-Bristol is a “low-tech” ventilator that can be used for treatment of COVID-19 in developing countries.

Written by: Tif Ho


The Challenge

On March 11, 2020 the World Health Organization (WHO) declared COVID-19 a global pandemic. As the number of cases of the disease has risen, countries have faced an increasing shortage in medical supplies. Amongst this dire shortage has been ventilators.

Ventilators are an important last-resort tool for treating COVID-19. While these machines are by no means a guarantee of survival, they can reduce fatality for extreme cases of COVID-19 that involve Acute Respiratory Distress Syndrome (ARDS). ARDS results from vascular damage to the lungs so that individuals cannot get enough oxygen to their bloodstream, causing major organ failure and death.

For some hospitalized COVID-19 patients, ventilators are the difference between life and death. Ventilators perform two critical functions for individuals who cannot breathe on their own. These functions are: (1) pulling oxygen into lungs and bloodstream, and (2) clearing out carbon dioxide.

In fact, UK-based medical professional, Emilio Garcia, states, “COVID 19 is a terrible disease that affects different people differently but most commonly causing type 1 and type 2 respiratory failure. This means people will need increasing amounts of oxygen. But once they develop type 2 respiratory failure due to tiredness, the only way to support them is to perform mechanical ventilation. Mechanical ventilation allows them to overcome the work of breathing but also to administer variable amounts of oxygen.

According to pulmonary and critical care specialist, Dr. Colin Cook, with the use of a ventilator, the mortality rate of COVID-19 patients is in the 20% to 30% range. Problematically, manufacturers and distributors have been unable to meet the forecasted demand for 880,000 ventilators globally.

The Solution

As COVID-19 spread throughout the world, U.K. designer Darren Lewis started the OpenVent-Bristol project for the purpose of creating an open-source ventilator for Coronavirus patients. Lewis works for Dyson’s new product team in the U.K. and has extensive experience in creating and prototyping new concepts. In an effort to apply his skills to the COVID-19 pandemic, he reached out to individuals through his personal network and through LinkedIn, bringing together a team of talented volunteers. The OpenVent-Bristol team is made up of project lead Darren Lewis, mechanical engineer Ross Goodwin, electronics designer Angus Thomson, software developer Donald Robson, and safety engineer Sam Riley. In March 2020, the team created an open-source design for a ventilator.

OpenVent-Bristol Ventilator-Diagram-Version 1.0

OpenVent-Bristol Ventilator Diagram, Version 1.0. This design was created in March and has been superseded by newer prototypes.

Soon afterward, several U.S. volunteers started the Offset Ventilator project in order to combat COVID-19. This talented team includes Brian Finch, Christian Taran, Jonas Fehr, Clay Gillmore, and Ammon Dayley.

The Offset Ventilator team found the OpenVent-Bristol project and began working on a ventilator build. Later on, the Offset Ventilator team reached out to the OpenVent-Bristol team to collaborate, and in recent weeks, the two teams have come together under the OpenVent-Bristol name, led by Darren Lewis.

In order to deal with the challenges of availability and costs, the OpenVent-Bristol team has designed a ventilator that has numerous advantages over traditional ventilators.

Traditional ventilators are complex, which causes delays in manufacturing and distribution and also increases cost. In contrast, the OpenVent-Bristol ventilator is designed for rapid production and cost-effectiveness.

Firstly, the OpenVent-Bristol ventilator is an open-source design, which means that anyone with the capabilities can manufacture it.

Secondly, the ventilator is made from readily-available materials and manufacturing processes, thereby reducing the need for complex materials and processes. This decreases the costs associated with building and enables the manufacture of the ventilator in countries with less capable manufacturing facilities and unstable supply chains.


OpenVent-Bristol Ventilator Prototype, Version 3.0.

The OpenVent-Bristol ventilator is a mechanical ventilator. It is constructed from a laser-cut stainless steel sheet that provides strength, water resistance, and biocompatibility (meaning that the ventilator is created from materials that are safe for patient use). An LCD user interface displays easy-to-read values for airway pressure and tidal volume, while a membrane button panel minimizes crevices for germs to hide. The ventilator includes a simple mechanism that allows it to be mounted to a motor and a standard 22mm tapered push-fit-air outlet that is compatible with existing tubing.

An adjustable PEEP valve maintains positive pressure at all times, whereby air is blown into the lungs rather than sucked in. This is important because many patients with extreme COVID-19 cannot draw in air on their own.

Additionally, in the OpenVent-Bristol ventilator, a Bag Valve Mask (BVM, proprietary name AMBU) is used – providing familiarity to medical professionals worldwide. Additionally, the ventilator includes visual monitoring for visual feedback of bag compression and of airway pressure. As a result, the ventilator is intended to be simple and intuitive for medical professionals to use.

OpenVent-Bristol features include the BVM (top left), PEEP valve (top right), and visual monitoring (bottom).

Feedback from Medical Professionals

Project Lead, Darren Lewis, has sought feedback on the OpenVent-Bristol ventilator from several medical professionals. These individuals include Emilio Garcia and Daniel Steman, a respiratory care manager at Keck Medical Center in California. 

With regards to the ventilator, Garcia says, “This ingenious device allows the use of a simple and ubiquitous self-inflating bag, commonly referred to as AMBU bag, as a ventilator. In places where more sophisticated ventilators are not available, this product can become invaluable as it will allow the support of patients in respiratory failure.

The OpenVent-Bristol design is simple to use and has a good battery life which allows the patient to be transferred between facilities. As its centre mechanism is an Ambu bag. Due to its adaptive modes, lung protection is simple as it allows spontaneous breathing and can be pressure limited. Whereas is not a substitute for a more sophisticated ventilator it can become invaluable in places where there is a crisis and a lack of equipment.” 

Steman follows this up with, “We know that having a ventilator is key to the survival of patients with respiratory failure regardless of COVID. This new situation with the pandemic has caused difficult decisions to be made regarding who should get the privilege of being mechanically ventilated and this is not something medical professionals are used to doing. The OpenVent-Bristol design ventilator may help us avoid these difficult decisions and instead allow for the standard of care to be unchanged.

One very cool feature of the OpenVent is that it has a simple spontaneous mode of ventilation. This is a key stand out feature that would aid in the weaning process and allow healthcare workers to liberate patients from the machines in the normal way. I have not seen this type of logic built into the other COVID response simple vent designs. Bravo.”


Current Progress

The OpenVent-Bristol ventilator was created to meet the standards of the U.K.’s Medicines and Health Products Regulatory Agency (MHRA). The team is also currently working on developing the ventilator to meet the U.S.’s Food & Drug (FDA) emergency ventilator standards.

Lewis says that the benefit of meeting these specific sets of regulations is that, due to their stringency of requirements, a ventilator that can meet MHRA or FDA standards will likely meet the majority of health standards of other countries as well.

Currently, the team is on its third prototype of the ventilator, with the V2.0 prototype having successfully undergone a performance testing with a sophisticated test lung at the National Physical Laboratory in the U.K.

OpenVent-Bristol-Contact Form on Website

How You Can Help

As OpenVent-Bristol progresses, the project team will continue to need help. The team is currently seeking:

  • Funding
  • Volunteers
  • Users who have used or may use a similar machine and who can provide feedback
  • Manufacturers, in the U.S. and elsewhere in the world, to take over building the ventilators
  • Buyers, including doctors and hospital procurement staff, to pre-order the ventilators

Want to volunteer?

Fill in the contact form at, or contact @Darren Lewis and/or @Cristian Taran on Helpful Engineering’s Slack.

Want to donate?

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