Before I go on to the novel ventilator prototype using almost exclusively standard parts available in any hospital (and many ambulances!); I was very happy to see that on Friday night New Yorkers took time out to applaud the health workers in the city.

Last year NHS staff and established artists produceed this charity record.

x YouTube Video

The smallest help you can give those fighting COVID19 is to slow the spread of the virus by social distancing and, most important, washing your hands.

One of the items of equipment that is desperately needed to stop people dying are ventilators. The UK and USA have co-opted car manufacturers to build existing machines and Dyson have a new design but these will take several months to tool up and start manufacturing.

A team from Oxford University and King’s College London took a different approach and came up with a prototype within a week. They have pitched it to the UK government. The joy is that it can be built mostly repurposing simple equipment that is already in the NHS supply chain. “The Face” interviewed Andrew Farmery from Oxford, one of the team involved.

As well as an academic, I’m also a consultant anaesthetist, so I deal with ventilating patients every week. That’s what I do. The design had come out of what the clinicians want. We were slightly worried at the start when Boris announced Land Rover and JCB were going to be making ventilators. I was slightly alarmed that they knew sod-all about ventilators and nobody had really taken the opinions of people like me and doctors and anaesthetists around the country. …. How many parts are there in this, and how long has it taken to iterate? It’s laughably simple in some ways. It’s a compressible bag, a bit like a child’s rugby ball. It’s a compressible squeezy bag – the sort you use to resuscitate patients who have collapsed from cardiac arrest. Ambulances carry them around. But we’ve trapped it inside a rigid Perspex [Plexiglass] box and we inject compressed air into the rigid Perspex box that squeezes this bladder and pushes air out through some valves which we already have, and inflates the patient’s chest. There’s a second set of valves that allows gas to come out of the patient’s chest and also out of the rigid Perspex box. So it’s a sort of electro-pneumatic device…. The electronics is based around a very simple circuit board called an Arduino – basically a tiny little circuit board used to teach kids about coding and electronics. It’s basically a toy, but that’s what the prototype is based on. We might even base the whole thing on that. It depends on whether we can knock PCBs out quickly enough. So the control engineers are still working on that, refining it. You’ve got to tell the solenoid valve what to do and then you’ve got to measure and monitor the pressures at various points with sensors to make sure that the solenoid is doing what you told it to do. That’s classic control engineering and they love that sort of thing, and they’re off on it already.

The control circuits are the main non-standard parts but Sony have offered to produce the printed circuit boards in a plant that has been shut down in the emergency.

x Queen's grad student Andrew Orr (DPhil, Engineering Science) is working on @OxVent, a collaborative project to develop a simple but effective ventilator that can be produced in its 1000s per week during the COVID-19 crisis: https://t.co/RspGjfmsRz #remarkableresearch #unisupport pic.twitter.com/5PU74J3Ffb Ã¢ÂÂ The Queen's College (@QueensCollegeOx) March 27, 2020

The design is so new that they have not been able to run the prototype for long enough to prove the system works. Another member of the team, Professor Mark Thompson, explained to the Daily Express.

"So we obviously need to have many tens of these devices running for two weeks to really burn them and see whether or not we can get them to break. "So we need to the testing, both hardware and software. And we need to satisfy the Government regulations." After that the prototypes will need to be tried out on real patients. Prof Thompson said: "We need to get the hospital trusts on board to get their agreement so that we can try these things with patients.

While a 16 year old could assemble it, for quality control purposes the ones for the UK will be built by International Standard certified assemblers however I suspect this design might be very useful after the emergency is over. Most of the respirator uses repurposed standard equipment so the control boxes could be sent to facilities in poor countries to assemble the rest themselves — hopefully they will make it “open source” so the software could be distributed to program these simple prototype circuit boards.

Finally, a reminder of the excellent daily summaries of developments from Dr John Campbell on his YouTube channel. Loads more on there as background too.