Paul Waine wrote: ↑Thu Apr 16, 2020 1:06 pm
Is it fair to feel that the reason Dyson and other non-medically experienced firms partnered with firms with medical experience was a way to address the gaps that they would have in not having medical experience? Were they forming partnerships with firms with the required medical experience or where they, maybe as a result of their haste, partnering with firms that themselves didn't have the right medical experience and expertise?
In terms of the initial specification that the gov't (the gov't advisors) put out for ventilators. Were there errors in these specs? or are the clinicians now learning more about what is required to treat covid-19 patients in ICU and so are correctly upgrading the specifications?
There's been lots of examples of companies changing their production lines across all different needs during this crisis - including visors, hand gel etc. That obviously is to be applauded. However I do think ventilators is a much more nuanced and technical manufacturing problem. It appears many of these new technical departments are trying to design from scratch rather than adapt production lines to make existing designs. The only known ventilator company I'm familiar with that's been involved is Penlon - who it looks today as though they've had a design approved. The only Penlon machines I've ever used are some very basic theatre ventilators that we got rid of about a year ago so I'd be interested to see how they've improved their design. I'm not aware of any theatres/ICU in the country that routinely uses Penlon equipment especially for ICU patients. There may be questions asked today about ventilators but it has to be said that people like the CMO are in no way familiar with the technicalities of this field. Again I'd be interested to know who they've had to advise on this. The president of the Intensive Care Society (who's criticised the current plan) might have been a good place to start.
In terms of the specification I've just sat down and read the government guidelines and it does confirm my suspicions. First point to mention though is that Covid doesn't present any new challenges for us in terms of the mechanics of ventilation. We've not been caught out by the disease and had to invent new technology. The specifications however do seem pretty basic and they expressly state that any machine designs submitted won't have continued registration after the pandemic is over. It's a 25 page document and I won't labour all of the points but a few things stand out:
- they only have to provide one mode of ventilation and it's likely this will be a MANDATORY mode ie. the machine does all the work. As I mentioned this is fine for the first few days but less useful later down the line. Machines that synchronise with the patients own breathing efforts are what we need particularly as patients are requiring ventilation for 2-3 weeks.
- there is only a requirement to produce quite specific parameters eg. including the actual volume of gas delivered, the ratio of time spent in inspiration/expiration. These are really quite tightly defined with narrow ranges and don't give you very much scope to tailor the ventilation to specific patients. This also means higher risk of lung injury to the patient (which we know occurs with mechanical ventilation at the best of times).
- CO2 clearance: basic level is to have soda lime systems to clear CO2. This is fine and is what theatre ventilators need but again is a finite resource and we're already running out of this. The sophisticated ICU ventilators don't need this and ICU nurses aren't familiar with having to manage the implications of this. That's not their fault as they don't use these types of machines usually but we've seen a fair few examples of this already
- bog standard machines using oxygen as the driving gas ie. not for delivery to the patient but to power the parts of the ventilator that squeeze gas into the patients. Oxygen supplies are a worry currently.
So overall they've gone for the lowest spec to get production going but it's likely they've set the targets wrong for what's required. Yes the machines will work - much as during the polio epidemic of the past we had medical students hand ventilating patients. It works but it's not ideal. We have lots of more simplistic ventilators (but better than what's being proposed) already in our institution. I'm struggling to see how this policy improves things.
Of course the elephant in the room is staffing. A ventilator does not equal an ICU bed. An ICU bed is a bed with a ventilator plus a highly trained ICU nurse, as well as appropriate monitoring, blood pressure and kidney support as required. The current national model is one ICU nurse to 6 patients (with non-ICU ward nurse support) and one ICU consultant to 42 patients. No increase in equipment, whatever the standard finally produced, gets away from this inescapable fact. With one of the lowest ICU bed numbers in Europe I'm afraid this comes down to a policy decision.
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