Breathing new life into old technology

My first introduction to Exovent was in Sept 2020 I had just worked through the first wave of the COVID pandemic as an ENT surgeon at Imperial College Healthcare Trust where I had set up and taken part in the COVID tracheostomy service. The first wave had been an intense and worrying time in the NHS and at that time in early September all the signs were that we were heading into a second wave, which if history were to be believed was likely to be worse than the first.

Professor Howard, a previous trainer and mentor, called me and invited me to join an exciting project he was working on that would be of benefit to COVID patients. He had spent the previous 6 months working with a team of medics and engineers developing a modern negative pressure ventilator fit for the 21st century. For me negative pressure ventilation immediately conjured up images of “iron lungs” large bulky tanks seen in black and white pictures on the pages of virology textbooks. However, I was aware of the importance of their role in the polio epidemic in the 1950’s.

The project particularly appealed to me as it combined my medical and engineering background. During my ENT training I took time out to complete a PhD in aeronautics looking at airflow in the nose and sinuses, and since the start of the pandemic I had been working with the aeronautics team at Imperial and Mercedes F1 on aerosol containment devices.

Through my research into negative pressure ventilation, I was immediately struck with the huge potential for a modern device not only in the COVID pandemic but also for many respiratory diseases such as COPD & Pneumonia.   In Exovent the bulky old technology has been miniaturised and made lighter, the device encloses a patient’s torso and assists breathing by lifting the chest wall with negative pressure, resulting in lung expansion that draws air into the lungs. This is far more representative of normal breathing than the positive pressure ventilators currently used, which force air into the lungs. Exovent has the benefit of potentially preventing some of the ventilator induced injuries we have seen in the pandemic.

Having spent time working in developing countries I was acutely aware of the burden of respiratory disease seen there, and the critical shortage of equipment to support patients’ breathing.  This has been brought home through the harrowing images in the media of hospitals in low to middle income countries running out of oxygen during the pandemic.

As Exovent is mains or battery powered only and does not rely on an oxygen or compressed air supply to drive ventilation, it has massive potential in low to middle income countries where even before the pandemic respiratory disease was a leading cause of death in adults and children. My particular interest is in developing a paediatric low cost, simple to manufacture ventilator which can be operated and maintained in low-income countries. A low-resource device like this has the potential to save many lives, both in Covid-19 and other respiratory diseases too.


Catherine Rennie

ENT Consultant

Imperial College Healthcare NHS Trust

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