Low-cost ventilator could address shortage in developing countries

Ventilators are medical devices used by patients in intensive care units (ICUs) with serious respiratory diseases, such as tuberculosis and Covid-19. They mechanically support the breathing of patients.

The coronavirus pandemic led to a scramble to obtain many more invasive ventilators, as clinicians warned that there was a severe shortage of these devices to meet the needs of patients with severe cases of Covid-19. In the UK, engineering companies with no prior experience with these complex devices were encouraged by the government to turn their attentions to designing and adapting ventilators such that they could be manufactured at a greater pace.

Now, researchers from Imperial College have presented their design for the low-cost, simple 'Relavent' ventilator, which achieves all the performance requirements set out in the international standard for critical care ventilators. It also performs as well with a home-use oxygen concentrator as with pressurised gas supplies like those found in hospitals.

The majority of current ventilator designs use proportional valves and flow sensors, which remain in short supply over a year into the coronavirus pandemic. The Relavent uses widely available on-off valves instead. As on-off valves are harder for accurately controlling ventilation, the engineers combined four valves, a two-litre reservoir, an oxygen sensor, and two pressure sensors. This brought a prototype ventilator into the acceptable ranges for precision and accuracy specified in international guidelines, providing the performance necessary for the majority of patients that require ventilation.

Lead researcher Dr Joseph van Batenburg-Sherwood, of Imperial’s Department of Bioengineering, explained: “Our ventilators are inspired by the beauty of simplicity. Rather than using the complex control valves used in most ventilators, we conceived a way to use simple on-off valves to provide the high-level performance required of ICU ventilators. This way, we have made the technology much cheaper and less expensive to make and maintain.”

The design and testing process is described in a new paper in Frontiers in Medical Technology.

The researchers hope that, following funding and regulatory approval, the Relavent devices can be used in low- and middle-income countries, which have a historical shortage of ventilators. This will require development from the advanced prototype stage to a mass-manufacturable medical device.

“ICU ventilators made by big manufacturers have always been too expensive and complex for developing countries to buy and maintain, so many of the less affluent parts of the world simply have minimal access to ventilators,” said Batenburg-Sherwood. “In addition, most of the new ventilator designs created for Covid-19 were based on emergency short-term manufacturing and are not appropriate for long-term intensive care support.”

The researchers have launched a start-up, Phaedrus World Medical Ltd, which will seek investment to commercialise the ventilator.

Liz Hughes, CEO of Phaedrus World Medical Limited, said: “Relavent delivers simple yet high-performance mechanical ventilation. Its versatility enables access to respiratory support across many different treatment areas, and has the potential to save many lives. This has only been made possible by the efforts of the amazing Imperial College engineering team alongside clinical input from our medical advisor who has first-hand experience in our target markets.”

Professor James Moore, a co-author on the project, added: “We are keen to bring our ventilator to as many hospitals as possible to combat serious respiratory diseases worldwide. We have the right technology to help address this unmet medical need and hope to attract investment to help take it further.”