Emergency ventilators: from ideation to manufacturing
This article was written by César Garcia, researcher at La Hora Maker .
Welcome to the second article in this series on ventilators! As we’ve seen last week , ventilators are critical pieces of infrastructure. They must work reliably for long periods of time without missing a beat. Today we will uncover what are the different phases involved in developing one of these devices. Please, note that this process is a simplified one, based on current circumstances. It usually takes much more time to get one ventilator ready to market.
First stage is the ideation phase. In this initial stage, teams need to decide what technology they will use for their design. One of the most common these days is repurposing an AMBU, by operating it mechanically. There are other alternatives although like pneumatical, based on electro valves, etc, and some of the models approved in Spain involve techniques like High Frequency Jet Ventilation — that is a complete departure from the AMBU models!
Andalucía Respira Ventilator photo (Source: Junta de Andalucía press release ) Given that the device is going to be used by medical personnel, it’s really important to look at the clinically relevant parameters for these devices. The MIT E-Vent team has done a wonderful job documenting these clinical aspects . You can find the key ventilator specifications to consider on their site.
It’s also worth noting that not all ventilators are meant to work the same. Some of them are better tailored for emergencies, while others are designed to support the patient for longer periods. Mechanical ventilators are covered by several ISO norms like 80601-2-12:2020 . Several agencies have made the specifications available for free , to help new initiatives to develop ventilators against COVID-19.
Once you know which approach you would like to take, it’s time to start working on your first functional prototype. Most of the designs will require you to get sensors and valves, as well as basic medical supplies. As per the control unit, we would recommend you to take a look at the Arduino boards better suited to the task in this presentation by Dario Pennisi.
Getting your prototype to pump air is the first step. But you need to control the amount of air in a precise way. Too much-pressurized gas could damage the patient lungs while falling short could suffocate them too. There are two approaches to this issue — some ventilators keep track of the volume of air, while others focus on pressure. To test this, you will need a lung simulator — there are plain simple models to really complex ones. UK’s MHRA offers an extensive test suite for Rapid Manufactured Ventilator Systems (RMVS) for this crisis. You can explore the test at Appendix B.
Photo credits: MHRA’s diagram for the test circuit from the Rapidly Manufactured Ventilator System specification. If you are producing ventilators in the UK,...
