On March 15th of 2020, days after COVID-19 was officially declared a "pandemic," Dr. Stephen Richardson, a cardiovascular anesthesiologist and professor at the University of Minnesota, wanted to find a way to make emergency ventilators scalable — to design a breathing-assist machine that could be built by anyone, anywhere.
"I wanted to figure out: 'How could we increase our capacity in a matter of weeks?'" Richardson said in a presentation this month on Tech Briefs. "I knew we weren't going to be able to do it by building traditional ventilators."
As Richardson sat at home in March of 2020 — on his exercise bike, in fact — he asked himself: "What could we use to kind of scrap something together?"
Ultimately, the cardiovascular anesthesiologist assembled a team and a device. Richardson and a group of engineers built 3,000 FDA-approved emergency-use ventilation machines in 67 days.
A simplified explanation of Richardson's idea: Make a kind of miniature, automated ambulatory ventilation bag. The handheld "ambu bag" includes a self-inflating pouch, one-way valve, mask, and an oxygen reservoir, to help a patient breathe.
The resulting device —the "Coventor" — pumps the bag mechanically.
The Coventor has a 3D-printed or metal-stamped frame and mechanical actuator to stabilize and compress a commercially available ambulatory ventilation bag connected to the patient’s endotracheal tube and external compressed oxygen. The compact, cereal-box-sized device uses off-the-shelf components and does not require pressurized oxygen or air supply.
So, how does the Coventor stack up to traditional ventilators? After Richardson's presentation with Tech Briefs, an attendee asked the researcher:
"Compared to traditional ventilators, what are the limitations of your device?"
Read Dr. Richardson's edited response below.
Dr. Stephen Richardson: Traditional ventilators have a number of features that allow for really specific patient customization, like controlling the pressure that's delivered to the patient, both in the inspiratory and expiratory phase, helping to maintain the lungs open as the person exhales. Traditional ventilators also allow the specific control of the amount of oxygen that is in the air that's pushed into the patient, from down to the ambience of 21 percent up to 100 percent oxygen. You can put specific controls on the volume that goes in, so 300 ccs of air to 800 ccs of air. You can control the time that breath that goes in, and the time available for the patient to breathe out. Other features allow for patients to breathe spontaneously; if someone were to be quite awake but needed just extra oxygen, they could otherwise breathe on their own.
There are lot of customizable features on traditional ventilators. Those are very expensive because you need a lot of sensors and technology to go into a synchronizing breath. Safety features can sense when either side of the circuit — the one that delivers air to the patient and the one that receives it back — are disconnected, so that the caregivers are aware that this patient has been disconnected from the ventilator and immediate action is needed.
Our device doesn't have any alarms, and it has very limited control. The device will work with an oxygen tank or a wall oxygen source. There's a very simple attachment to add PEEP , or positive end-expiratory pressure, to help with oygenation. There's very little control over the volumes that go in, in the way that it is currently constructed.
It is possible to make modifications to do that, but as you change how hard you squeeze the bag, then, [you have to consider] the patients' lungs. If the patients' lungs are stiff, less air will go in; it's a very complicated dynamic.
For many aspects of patient care, we are provided with solutions by providers. We have very fancy ventilators in our operating room. We use very little of their capability, because we are in this mindset of "I want to have everything for that one, super-sick patient who could come to my hospital." Instead of having one super-special ventilator that we could use for that one patient, we just buy those features for every single ventilator that we have.
Our device is kind of stripping [the care] back to the basics of emergency hand ventilation: what would be needed to sustain life in an emergency. It has quite a bit of limitations compared to those traditional ventilators, for control that requires specific applications. There is a very limited function set, no control over pressure, no specific control over the volume [of oxygen]. We really control what oxygen goes in, what pressure stays against the lungs to help with oxygen, and the patients' respiratory rate.
Learn more about the Coventor .
Watch the full Tech Briefs presentation: From PPE to Testing: Emerging Technologies from COVID-19.
What do you think? Share your questions and comments below.