Teaching an old Doctor new tricks – my first year with Exovent

My name is Di and I’m a retired GP, an early member of the Exovent group, and an active member of the u3a – an organisation for those who like to learn new things and stay active.

A year ago there were 2 things I was using my medical knowledge for – as an expert member of a Research Ethics Committee, and giving lectures to u3a groups on medical topics that I felt were interesting to this older age group.

I had been asked to give a lecture to Fleet u3a Science and Technology Group on the HPV vaccine at the start of March 2020. I’d offered to add half an hour on the new coronavirus which was causing COVID-19. Neil – my physicist husband – and I were worried about what was about to happen with this new virus. We’d been plotting the UK cases on a spreadsheet and it looked like exponential growth to us – with a doubling time of 3-4 days.

However, on 5th March 2020 there were only 49 confirmed cases of COVID-19 and no deaths in the UK.

Looking back at that lecture, I am surprised at how much we knew already, including who was most at risk of dying of COVID-19. I gave my mostly over 65 year old audience a ‘look away now if you don’t want to know’ warning before I showed the age related death rates. Most of them didn’t look away.

What have we learned since then? The effect on the sense of taste and smell, the many and unusual effects on the lungs, the effect on blood clotting. The benefit of dexamethasone and anti-coagulants. How hard it is to ventilate these patients with standard positive pressure ventilators and the problems with the endotracheal tubes and the covid infected tracheas. Long COVID. And how to make and ethically test vaccines really quickly.

As for advice – the hand washing and the masks were in my lecture, and the warning that once you have the virus then you can pass it on to other people, and the only way to stop this virus is to stop this transmission. Now I would add – stay outside if at all possible when meeting others, or in very well-ventilated rooms, and have a full course of vaccine. And I’d have a slide on why we can’t afford to bet on new variants being milder.

Best of all I’d have a couple of slides on negative pressure ventilatory support and why we should be thinking about reintroducing it into main stream medical care all over the world, not just for COVID-19 but also for other forms of respiratory distress.

Two weeks after the March 2020 COVID lecture, my GP daughter sent us a post from Facebook. A civil engineer was trying to set up a group of doctors and engineers to build a modern iron lung.  The Iron lung was negative pressure ventilator technology that had kept tens of thousands of polio patients alive in the first half of the twentieth century.

Neil went into the garage and came out a few hours later to show me his proof-of-concept negative pressure ventilator made from a large plastic box with a vacuum cleaner with a simple electronic controller. It was clear to me that this was going to be possible from the engineering point of view. But I knew that NPV worked in polio patients who had normal lungs, but weak muscles. COVID-19 patients had working muscles and terrible lungs. Could negative pressure ventilators work for these very sick patients?  A little searching on the internet found medical research papers from Italy in the early 21st century showing that NPV did work well in sick patients with terribly infected lungs.

We joined the Exovent team just before the first UK lockdown.

23rd March 2020 was the start of the first UK lockdown – new COVID cases on that day 2335, and there were 76 deaths due to COVID.

Neil and I set to tinkering with the prototypes to see how to control chamber pressure, how to sense chamber pressure, how large a chamber could be evacuated using a vacuum cleaner motor. What might go wrong? What wouldn’t work?

In early May I went to Marshall Aerospace (a global company that were assisting exovent with design and prototyping) in Cambridge to meet up in person with some of the amazing anaesthetists and intensivist doctors and nurses that are part of the Exovent team.  We had only met for the first time at most 6 weeks before on conference calls, but, with the rest of the Exovent team and Marshalls engineers there was a professionally made Exovent sitting there for us to try out. From Facebook to device in 6 weeks!

The machine worked well and the data we took showed that a modern, light weight, torso only version of a negative pressure ventilator would be possible.



Deaths in the UK within 28d of a positive COVID test by 26th February 2021 – 143,000.

Global deaths – 12th March 2021 – 2,632,041 (Johns Hopkins).


At the end of my first year of Exovent I’m proud of what the team have achieved, and I’m looking forward to when NPV finds its place again in treating patients, in this country and around the world in places where this technology will bring breathing support to sick people.

Every time I give a lecture I try to work in NPV – next week I am mentoring some young people who hope to start their medical training at Oxbridge. They will be first thinking about how people breathe naturally, and then we will look at how using NPV which mimics natural breathing might work, and how it differs from positive pressure ventilation. You can never start too young – or too old!!!


Dr. Diane Downie

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