AddiVent

The design and development process for AddiVent was carried out during the 2020 Melbourne COVID-19 lockdown, with the team working from home in isolation for seven months. An extensive research phase was conducted to fully understand not only the landscape of existing low-cost ventilator designs, but the technical and medical requirements necessary for mechanical ventilation.

A Bag Valve Mask (BVM) squeezer design was chosen due to the maturity of research and development reached by other teams. From this research a technical criteria was defined, specifying the medical, technical, ergonomic and safety requirements for the device.

The team then worked through the detail design for AddiVent's various subsystems.

Development of the unique BVM squeezer mechanism took into consideration the specific requirements of the crowdsourced 3D-printed manufacturing approach.

The packaging design development ensured the electrical and mechanical components were safely housed in a modern and resolved body, improving the product perception from an engineering prototype to a quality medical device.
The final design comprises 18 purchased electrical components, 40 3D-printed PETG parts, and 3 laser-cut acrylic panels.

The final unit costs around $500 AUD per unit, significantly less than standard mechanical ventilation devices. A complete prototype was manufactured and assembled to validate our body design. This was delivered alongside a detailed design report and two research papers detailing the entire research and development process.

BVM ventilators have been developed elsewhere with some designs reaching high maturity in terms of their functionality, the E-Vent from MIT being a notable example. However, these machines lack a resolved body design, being more engineering prototype than hospital ready medical device.

The challenge for Addivent was to maintain those attributes of a low-cost device intended for rapid, small scale production, and yet still deliver a high-quality, reliable and safe product ready for use in a hospital setting.

The body design is inspired by modern medical device aesthetics, and safely houses the mechanism and electronics whilst maintaining functionality and usability. It is made from 3D-printed PETG components, a strong and chemically resistant material that can be reliably printed on home desktop 3D-printers.

The removable cover protects the mechanism while in use whilst maintaining easy access to the BVM inside. The large screen and simple interface provide a significant improvement over similar devices, being better suited to the medical professionals who will be operating the device.

All parts have been designed for 3D-printing through the crowdsourced manufacturing method, with large parts broken down into smaller, printable pieces. The assembly process requires no specialised tools, using M4 bolts and epoxy adhesive to construct the device.

Despite the limitations of crowdsourced manufacturing AddiVent still delivers a mechanical ventilator ready to be used in a hospital by medical clinicians.

The need for these devices is something we are lucky to have not yet faced in Australia, however other countries have not been so fortunate. Repeatedly we have seen the potential for health services to become overwhelmed, requiring extraordinary decisions on how to triage the limited resources. This is where

AddiVent can help, by providing a workable stopgap solution that can be manufactured in response to the demand.

AddiVent is designed specifically to be manufactured quickly and easily wherever it is needed through the crowdsourced method. This approach uses alternative resources to traditional manufacturing processes that may be already stressed during a crisis scenario. Manufacturing capacities of 30 ventilators per week are achievable with a volunteer manufacturing resource of only 30 - 40 home desktop 3D-printers.

Development of the BVM squeezer mechanism took into consideration the specific requirements of this 3D-printed and crowdsourced manufacture approach. Distributing manufacture to a dispersed and isolated pool of resources, with varying 3D-printer models and capabilities, means the fundamental operation of this device cannot rely on accurately made parts and assemblies and limits the materials available to use.

The unique pull-cord design is AddiVent’s solution to this challenge; eliminating any high wear mechanical interfaces, using only simple and easy to find hardware, and not requiring high tolerances for its operation.

AddiVent is a potentially life-saving device, presenting a viable option for mechanical ventilation to patients that would otherwise be turned away. It is entirely manufactured through community engagement; local people manufacturing devices for their local hospitals to save lives from their community.

It can be made cheaply and quickly in response to emergency scenarios, such as COVID-19, to provide a life-saving device where there would otherwise be none.