In many parts of the world the COVID-19 pandemic is causing shortages in hospital space, staff, medical supplies, and equipment. Severe cases may require breathing support, but there are only so many ventilators available. With that in mind, MIT is working on FDA approval of an emergency ventilator system (E-Vent). They have submitted the design to the FDA for fast track review. The project is open source, so once they have approval the team will release all the data needed to replicate it.
The design is actually made simple by using something that is very common: a manual resuscitator. You have doubtlessly seen these on your favorite medical show. It is the bag someone squeezes while the main character struggles valiantly to save their patient. Of course, having someone sit and squeeze the bag for days on end for thousands of people isn’t very practical and that’s where they’ve included an Arduino-controlled motor to automate the process.
The tricky thing is that, forcing air into your lungs isn’t always good for them. Even healthy lungs can be stressed by too much inflation and people who already have lung problems may be able to handle only a tenth of what a healthy set can manage. That’s why the device needs a closed loop control system that monitors pressure from the patient and modifies the flow.
Any solution should be utilized only in a healthcare setting with direct monitoring by a clinical professional. While it cannot replace an FDA-approved ICU ventilator, in terms of functionality, flexibility, and clinical efficacy, the MIT E-Vent is anticipated to have utility in helping free up existing supply or in life-or-death situations when there is no other option.
Further, any low-cost ventilator system must take great care regarding providing clinicians with the ability to closely control and monitor tidal volume, inspiratory pressure, bpm, and I/E ratio, and be able to provide additional support in the form of PEEP, PIP monitoring, filtration, and adaptation to individual patient parameters. We recognize, and would like to highlight for anyone seeking to manufacture a low-cost emergency ventilator, that failing to properly consider these factors can result in serious long-term injury or death.
This isn’t a unique idea, and the MIT team provides links to other similar projects. The team’s work is not totally online yet, because they are still testing. For example, the acrylic apparatus that squeezes the bag may not hold up to the repetitive stress very well. The team may look to other projects that predated the crisis. For example, have a look at the AIR device presented at a conference last year in the video below. There’s also this interesting document from a Johns Hopkins resident.
Almost as interesting as the device itself is the comments people are leaving about the design. It is a great example of how the Internet opens up totally new ways to collaborate on a critical problem like this one.