April 17, 2020 | ProgressTH
We've recently begun developing a low-cost opensource mechanical ventilator. We're using cheap and easily sourced electronic components including a locally-produced Arduino Uno-compatible microcontroller (Gravitech's Lambda board), high-torque servos used by hobbyists, and 3D printing to build our prototypes.
Our project is up on Thingiverse here. It includes some STL files for printing as well as a SketchUp 2017 file with all the parts, an assembled and labeled view, an exploded view, and the parts laid down for 3D printing.
The ventilation itself is accomplished using a handheld resuscitation bag, with our prototype essentially automating the compression of the bag. Unlike a human hand, we can program our prototype to compress the bag at precise rates and for precise depths thus controlling both the rate at which air is delivered to a patient as well as the volume.
Background
Among these shortcomings is a lack of accessible and affordable essential medical equipment, particularly ventilators.
Companies that make them keep their designs a secret and often overcharge customers for their use creating scarcity especially when they are needed most.
While there are many news stories circulating today of teams racing to build low-cost opensource mechanical ventilators, this idea isn't new nor is the necessity for a cheaper and more accessible mechanical ventilator something that just recently came up.
An MIT project described in a paper titled Design and Prototyping of a Low-cost Portable Mechanical Ventilator, is dated 2010 and specifically notes that shortages of mechanical ventilators aren't just a problem for people who can't afford them, but even in developed countries where emergencies (such as an outbreak, an accident, or natural disaster) create an influx of demand that can't be met because of the difficulty of buying additional mechanical ventilators that are complicated, expensive, and in short supply.
The MIT paper presented two prototypes of a vastly cheaper and simpler mechanical ventilator using an opensource microcontroller, a cheap motor, and a cheap, easily sourced handheld manually squeezed resuscitation bag also known as ball valve mask or BVM.
You'll see emergency workers using BVMs to help supply air to a patient until they can be brought to the hospital and connected more permanently to mechanical ventilator. MIT's project sought to automate these handheld BVMs thus either extending the amount of time a patient can wait before a mechanical ventilator was available, or even supporting the patient throughout the duration of their hospitalization.
This story from China describes a young man, the victim of a car accident, who has been kept alive for years with a BVM squeezed manually by family members who took turns around the clock.
The family also created a crude electro-mechanical system to automatically squeeze the bag for them when electricity was available.
Low-Cost Opensource Mechanical Ventilator is a Worthy Long-Term Project
Creating a solid design that reliably automates BVMs would create a vastly cheaper alternative to expensive mechanical ventilators produced and sold by large biomedical technology corporations. They could be easily manufactured and distributed to help cover day-to-day cases or be stored on hand in the case of an emergency and not only help out in emergencies, but help make ventilation an affordable option to anyone, anywhere.
Our Applied Technology Lab is currently working on just such a solution, alongside many other teams around the globe working on similar solutions. While they are attempting to address the Covid-19 outbreak, we believe that most of these devices will not be ready in time and see the project as a much longer-term objective. That doesn't mean that any of these teams are wasting their time.
The need for cheap, opensource, and accessible biomedical equipment is a long-term problem and all of these ventilator designs will serve the purpose of solving that problem regardless of what impact they make regarding Covid-19 in the short-term. We hope that many of these teams see the value of this work outside the Covid-19 context and continue working on their projects long after the hysteria subsides... and on many other projects that require similar attention.
Our opensource ventilator project was inspired by the work of many of these teams, particularly those using BVMs and servo-driven linear actuators, but information provided by all the teams regarding specs, problems they've encountered and how they overcame them is what allowed us to whip up this initial prototype in less than a week. This is the power of opensource collaboration.
If you find yourself frustrated with the way things are, start investing in learning the skills required to change it yourself. Depending on the people who knew this problem existed and did nothing to solve it for years is not the answer.
Look for updates on our blog here, on Thingiverse, or Cults3D. If you have questions, comments, or inquires please contact us here.
