https://www.youtube.com/watch?v=QZ1g1FmOCdQ&ab_channel=DarrenmLewis

https://youtu.be/8yvML1Xkf6o

Please see website for project overview: https://openventbristol.co.uk/

To learn more about the project please click here: https://openventbristol.co.uk/wp-content/uploads/2020/12/OpenVent-Bristol_booklet-Dec-2020.pdf

To see our open source design release please click here: https://docs.google.com/presentation/d/e/2PACX-1vRULcGT6Jc9GJDVb21LnrkGW9OiDjC7QJ2lRb0DsiA6KYFimniAMwYWqoMfq-0fJhvekxmhCl915fU4/pub?start=false&loop=true&delayms=3000

•  Project title: OpenVent-Bristol
•  Shortname: OVB
•  Short description: OpenVent-Bristol is an open source COVID-19 ventilator designed to be manufacturered rapidly and easily and at very low cost, this is enabled by a pure and simple design that uses only readily available parts and manufacturing processes openventbristol.co.uk. It's designed to fill the market gap for low-cost rugged ventilators to be used when existing ventilators are not available (in particular for the developing world).
• Team composition:
• Darren Lewis - Project lead & founder
• Carey Becker - Project manager
• Rick Collins - Electronics engineer (FPGA)
• JT Miller - Electronics engineer (FPGA)
• Thomas Voreis - Electronics engineer (FPGA)
• Jeff Southerland - Electronic engineer
• Shrouk El-Attar - Electronic engineer
• Laura McGugan - Electronic engineer
• Kamilla - Electronic engineer
• Sakib - Electronic engineer
• Jonas Fehr - Mechatronics engineer
• Donald Robson - Embedded software engineer
• Alex Luisi - Embedded software engineer
• Kian Ming-Yak - Mechanical engineer
• Ross Goodwin - Mechanical engineer
• Abu J.Ahad - Risk Manager
• Daniel Dineen - Systems engineer
• Dheeraj Menghi - PR
•  Keywords associated with the project. Pandemic, ventilator, COVID-19, volunteering, rapid manufacture

1. Slack channel within OpenCovid19 slack: https://open-covid19.slack.com/archives/C01S15H2FFD
2. Slack channel within Helpful Engineering: https://helpfulengineering.slack.com/archives/C010FSME97W
3. Website: openventbristol.co.uk
4. To learn more about the project please click here: https://openventbristol.co.uk/wp-content/uploads/2020/12/OpenVent-Bristol_booklet-Dec-2020.pdf
5. To see our open source design release please click here: https://docs.google.com/presentation/d/e/2PACX-1vRULcGT6Jc9GJDVb21LnrkGW9OiDjC7QJ2lRb0DsiA6KYFimniAMwYWqoMfq-0fJhvekxmhCl915fU4/pub?start=false&loop=true&delayms=3000

1.0 Introduction 

1.1 Problem and Background: Many developing countries don't have sufficient ventilators, in particular for the COVID-19 pandemic but this also applies in general non-pandemic scenarios. Traditional hospital ventilators cost upwards of £20k. OpenVent-Bristol aims to cost less than £800.

1.2 Solution summary in simple terms: OpenVent-Bristol was designed from the beginning to be rapidly manufacturable; enabled by a remarkably simple design with cut-down functionality and use only of readily available parts and manufacturing processes. Our device is also designed to be modular which allows teams to adopt individual sub-systems of our design.

1.3 Solution summary in technical terms: Comprising just 2 general purpose ventilation modes; a full ventilation mode (sedated) and a patient triggered ventilation mode (conscious).

1.4 State of advancement of the project: We have built and tested 3 stages of prototypes listed below:

• V1 prototype: https://www.instructables.com/COVID-19-Rapid-Manufacture-Ventilator-BVM-Ambubag-/
• V2 prototype: https://www.instructables.com/OpenVent-Bristol-V20-COVID-19-Rapid-Manufacture-Ve/ this prototype was tested at the National Physical Laboratory with an ASL 5000 test lung and showed good results against the MHRA ventilation performance spec in both VCV and PSV mode. Test results can be found here: https://drive.google.com/drive/folders/1sIlUzyKECbZhti_AsIl4kUTU4YTzxcbe?usp=sharing
• V3.0 prototype was only internally documented with no open source release yet as a number of things needed to be fixed which will be embodied in the V3.1 prototypes. The V3.0 was however mechanically tested and left to run on a life test for longer than the total life time required my MHRA.

We are working on the final design V3.1. Once the final design is complete

• it will be performance tested against ventilator performance standards at an indipendent scientific test house (National Physical Laboratory)
• the designs will be passed onto our manufacturing partners in Brazil and India, who are both keen to take our project to the next stage of production and market release.
• and the designs will be released as open source on our website

1.5 Project Timeline: The bullet point list below shows a rough time scale for our expected progress for completion of the V3.1 prototypes. Our manufacturing partners and our open source design release will be updated continously

• WK 12 - Receive mechanical enclosures
• WK 18 - Receipt of custom PCBs
• WK 18 - All software written
• WK 20 - All electronic hardware and software tested
• WK 21 - Ventilation performance testing at the National Physical Laboratory, London
• WK 21 - Begin long term durability testing

To make this all possible, as well as the skilled engineers in our team we have a list of sponsoring companies to help us with; PCB manufacture, PCB assembly, mechnical fabrication, circuit design and label manufacture. And we have 3 specilised medical professionals in the form of lead anesthetists based in different countries around the world.

2.0 Project Implementation

2.1 Solution, research, or intervention? (choose accordingly) (1000 words max)

•  Solution: OpenVent-Bristol was designed from the beginning to be rapidly manufacturable; enabled by a remarkably simple design with cut-down functionality and use only of readily available parts and manufacturing processes. Comprising just 2 general purpose ventilation modes; a full ventilation mode (sedated) and a patient triggered ventilation mode (conscious).

Our design is based around an Ambu-bag or BVM (Bag-Valve-Mask) because these devices already have medical device approval for use in ventilation systems and they are readily available in most countries health care systems at low cost. Our enclosure houses a brushed DC geared motor which compresses the bag to deliver pressurised air to the patient. Pressurised air delivery is controlled by a microcontroller based on inputs from the ventilation sensors (flow rate, pressure and oxygen). The motor and motor arm reset their position using homing switches (the switches have redundancy). The motor has 2 cooling fans which operate when necessary to keep the motor temperature low. There is a series of visual (LED) and audiable (speakers) alarms according to the relevant electrical ventilation standard.

Please see system archetecture diagrams below. NOTE: OpenVent-Bristol V3.1 is designed to be modular which enables teams to adopt any of the following sub-systems individually if they wish:

• The control circuit board, comprising safety critical functionions; UI, alarms monitoring and triggering, reading sensors for triggering alarm states & FPGA as well as a built in microcontroller that communicates with the safety critical alarm system
• The power circuit board, comprising; mains power input, battery connections, air delivery drive (motor driver + position switches) and cooling fans
• Our own design of flow sensor; very simple and rapid manufacture enabled to improve control of supply chain
• The mechanical enclosure and labels

For example, a team could take our circuitry and mechanical design but swap out our AmbuBag for a different air delivery mechanism.

For safety, redundancy and ease of verification (software and hardware) we wanted to include electronic hardware backups for our alarm triggers which will still trigger alarms (audiable and visual) if the software fails. We soon realised this would not be possible with simple comparitors because most of the alarm triggers require some calculation of the sensor readings, for this reason we split all "safety critical functionality" (i.e. everything relating to the alarms including reading ventilation sensors and the UI) onto an FPGA as we were informed this would be easier to verify from a safety point of view and splitting out functions onto different processors helps provide redundancy.

The ventilator is compatible with all standard off-the-shelf airway circuitry components. Airway circuit diagram for use with OpenVent-Bristol is shown in the image below:

•  Research: We have chosen every aspect of our design according to the following:
• The MHRA_RVMS_v4 which is a document put together by the UK's medical regulatory body describing the basic functonality required for an emergency use ventilator
• The FDA EUA, which lists a number of engineering standards put together by the US medical regulatory body
• Advise from specilist highly qualified medical doctors. A UK based lead consultant anesthetist, a US based head of intensive care and an anesthetist based in Austrialia

Based on all of this knowledge we have put together the following:

• our own requirements documentation
• system documentations and archetecture diagrams
• risk assessments (in line with FDA guidelines)

All of this means that we are confident our device can be made safe and suitable for it's purpose.

•  Intervention: Our overall goal is to to allow poorer parts of the world access to good and safe ventilation systems. More specifically we want to complete our design, test it, update our open source release and pass designs onto our partners in Brazil and India for manufacture.

2.2 Methodology (500 words max): Our full existing open source design release can be found by clicking the "build" button on our website https://openventbristol.co.uk/. Our methods and tools used in creating our design are listed below:

• Design brief and identifying standards:
• The MHRA_RVMS_v4 which is a document put together by the UK's medical regulatory body describing the basic functonality required for an emergency use ventilator
• The FDA EUA, which lists a number of engineering standards put together by the US medical regulatory body
• Advise from specilist highly qualified medical doctors. A UK based lead consultant anesthetist, a US based head of intensive care and an anesthetist based in Austrialia
• Project requrements were formed based on the information from the sources above. Information such as:
• a mind map in Xmind of the different sub-systems and how they interact
• a system requirements document
• functional requirements documents with specific requirements for the sub-systems
• System architecture diagrams of our solution can be found by clicking the "build" button on our website https://openventbristol.co.uk/
• Mechanical enclosure: Designed in CAD, viewable on GrabCAD. Enclosure will be made from 1.2mm stainless steel grade 304 (medical approved), laser cut and CNC bent. Some parts were 3D printed and itterated for testing purposes, this allowed a full durability life test to test the machine for longer than it's entire required life time.
• Flow sensor: Our design allows for either an off the shelf flow sensor (the SFM3020/SFM3019) or a flow sensor that we have designed specifically to control the supply chain. Our own designed flow sensor works by creating a pressure drop over an orifice restriction, measures the pressure drop using a differential pressure sensor then calculates flow rate. Flow rate measurements are compensated for ambient temperature, ambient pressure and downstream air pressure.
• Circuit boards: Top level electronics block diagram can be found by clicking the "build" button on our website. There are 2 PCBs both designed in KiCAD (open source PCB design software).
• Software: Software is split into 2 parts:

1. FPGA software covers all the safety critical functions that relate to the alarms, this includes reading the sensors and operating the UI
2. Microcontroller software covers controll of the motor and overall air delivery system

• Full system testing has been and will be conducted by the National Physical Laboratory (NPL) in London. They conduct ventilation performance testing according to standards.

2.3 Results/Expected results (500 words max)

Past results ventilation performance testing: The OVB V2.0 prototype was tested at NPL under PCV (Pressure Controlled Ventilation) and VCV (Volume Controlled Ventilation) modes with good results matching up with the preformance spec requested by the MHRA. Test results can be viewed here: https://drive.google.com/drive/folders/1sIlUzyKECbZhti_AsIl4kUTU4YTzxcbe?usp=sharing

The version 2.0 prototype can be found here: https://www.instructables.com/OpenVent-Bristol-V20-COVID-19-Rapid-Manufacture-Ve/

Past results durability testing: The prototype performed for longer than it's requiremed minimum lifetime of 2 weeks continous running. Many design changes were made to improve the running life but not all can be tested until the V3.1 prototypes are available. Durability test report for V3.0 prototype linked here: https://drive.google.com/file/d/15hUuYAJKskkMPG9TYK0blUePAemYC8Tu/view?usp=sharing

Expected results for V3.1 prototypes: We expect to see good results for ventilation performance in both PCV (Pressure Controlled Ventilation) and PSV (Pressure Support Vention) modes. Life test is expected to last for between 3-10 weeks of continous running.

3.0 Safety, quality assurance and regulation 

3.1 What steps have you taken to ensure your solution’s safety?

• identified required industry standards for safe ventilators (every decision on our design was made in consideration of the relevant standard)
• for example ISO60601:1:2007 tells us how to spec our LEDs and speaker for sounding alarms and the LED colour and distinct speaker 'chirp' for alerting low, medium and high priority alarms
• bio-compatibility standards
• Software (BS EN 62304:2006+A1:2015) and electronics standards, which led us to separate out control of alarms (and everything associated with alarms) from the air delivery control sub-system.
• a top-down requirements derivation process to understand what each sub-system needs to be capable of, starting with system level requirements then breaking down to functional
• advise from a medical quality manager (QA-RA) on what documentation we should produce
• a risk assessment/hazard analysis in accordance with FDA guidelines. Identified risks have been mitigated in the design to prevent failure or where not practical to mitigate in the design, these risks will be documented and carried forward to the manufacturer. This includes every type of possible failure of the device and risk to the user e.g. electrical or software failures, identification of appropreiate medical grade materials etc.
• performance testing by an indipendent, scientific, well renouned test house

3.2 Have you planned the conduct of your manufacturing process that ensures quality, what are the steps you have taken? How advanced are you in this (if applicable)? For the most part this is considered out of scope of our project as in the medical world the manufacturer takes full legal liability for the device they produce and they are responsible for the submission to the medical regulators and the medical device manufacturer usualy must be certified to ISO13485 quality standard in order to make a submission for medical device approval, our group simply won't qualify for this. We do however demonstrate a due diligence to ensure manufacurers who take on our design share morrally acceptable values, we have also designed the ventilator using manufacturing processes that certianly have the potential to produce good quality components capable for passing medical approval processes. Our aim is to provide a very comprehensive starting point for an ISO13485 certified manufacturer to take from working design and validate/verify under their own quality assurance processes (QMS) and submit for medical approval.

3.3 Will you need assistance with the regulation system? No regulatory assistance required. Our previous quality manager advised what documentation we should produce, this will be passed to our manufacturers who will be responsible for the regulatory sumission.

3.4 Have you talked to medical staff about the feasibility of your project? What did they say? Yes, as described above we have 3 highly qualified specilist doctors who have been advising on various aspects of the project.

3.5 Have you planned the testing, verification and validation of your solution? How advanced are you? 

• Verification: We have our design brief, identified standards and medical professional advise which can be considered the "user needs". This has been distilled into system level and functional level requirements which the design will meet. Our design is continously verified against our user needs.
• Validation: We have an indipendent testing partner arranged for final validation testing of the overall system. We are working on a test plan for validating our sub-systems against our requirements.

4.0 Impact, issues and risks

4.1 What impact do you feel your project could have? Our overall goal is to to allow poorer parts of the world access to good and safe ventilation systems, whether it's in a pandemic or in more every-day scenarios.

4.2 What do you think would make your project a success?

• roll out to more manufacturers across the world (contacts in different countries required)
• funding to buy materials for prototyping
• possibly more electornics and software resource
• marketing to raise awareness of our project

4.3 Please list the known issues, potential risks, grey-areas, etc in your project

• entire team is working on a voluntary basis and everybody can only use as much time as they can spare which can change from week to week. This means delivery time estimating and increasing the pace of work can be problematic
• It's not guaranteed that our manufacturing partners will wish to produce our design
• if OVB V3.1 is to be designed as an ever-day use ventilator (not pandemic specific), it may be beneficial to redesign parts of it to increase the running life. Parts restricting life are; the ambu-bag and the brushed motor.

5.0 Originality

5.1 What other projects on JOGL are like yours? Search for them and Link them!

• https://app.jogl.io/project/162/PCEvent
• https://app.jogl.io/project/151/Breezy
• https://app.jogl.io/project/524/TheAnkaVentProject

5.2 Is this an innovative project? What makes this project different if it’s unique on JOGL?

The innovation and uniqueness of our project comes from the simplicity of the design and use of only readily available components and manufacturing processes with fast lead times which enables very rapid manufacture of the device. Also the fact that it is all open source means that anyone could benefit in some way from our work.

5.3 Is there already an open source version of this project? Yes, see https://openventbristol.co.uk/ for previous version releases

6.0 Team experience

• Darren Lewis, UK - Project lead & founder
• Carey Becker, US - Project manager
• Rick Collins, US - Electronics engineer (FPGA)
• JT Miller, US - Electronics engineer (FPGA)
• Thomas Voreis, US - Electronics engineer (FPGA)
• Jeff Southerland, Taiwan - Electronic engineer
• Shrouk El-Attar, UK - Electronic engineer
• Laura McGugan, UK - Electronic engineer
• Kamilla, UK - Electronic engineer
• Sakib, UK - Electronic engineer
• Jonas Fehr, Denmark - Mechatronics engineer
• Donald Robson, UK - Embedded software engineer
• Alex Luisi, UK - Embedded software engineer
• Kian Ming-Yak, US - Mechanical engineer
• Ross Goodwin, UK - Mechanical engineer
• Abu J.Ahad, UK - Risk Manager
• Daniel Dineen, UK - Systems engineer
• Dheeraj Menghi, US - PR

Sponsoring company capabilities; PCB manufacture, PCB assembly, mechnical fabrication, circuit design and label manufacture. And we have 3 specilised medical professionals in the form of lead anesthetists based in different countries around the world.

7.0 Funding and Costs

7.1 Please provide a costing of your project be as detailed as you can, all funding requests must be transparent and be for specific needs. The maximum grant is 2000 euros for new projects and 4000 euros for already established JOGL projects. Smaller grants are more likely to be funded. If no grant is required, request no funds in the form.

7.2 How is your project being funded so far? £2,572.63

7.3 How much funding do you need and how do you plan to use that funding?

In addition to the funding we already have we require £1720 (2000 EUR) to pay for flow sensors and test lungs to the quantities and prices below:

• SFM3020 flow sensor £85 quantity of 12 (4 will go into full product prototypes 5 will be shipped to our manufacturing partners in Brazil and 3 will be shipped to the US with the bare circuit boards for validation testing)
• A test lung called a "quick lung" system from ingmar medical at a cost of £700

Ideally we require 4 test lungs (at cost of £700 each), which will give us one for each of our new ventilator prototypes.