<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<p><br>
</p>
<p>There are ventilators and ventilators. AFAI can make out from the
numbers I've looked at, around half of the people who need
top-of-the line ventilators will die anyway - there's only so much
you can do in the face of a cytokine storm. Others will do
perfectly well on the much simpler CPAP devices. Of the three
approaches that Dewi mentions, ramping up production of CPAP
machines is probably the most effective <i>single</i> measure. As
regards the other two options:</p>
<p>* option 1 cannot be effective in the short-to-early-mid-term
because of the <i>systemically raised global demand</i> that a
pandemic causes - this one will take time to produce results yet
could even, in the longer term, result in a glut on the ventilator
market (probably good news for ICUs in China ;-)<br>
</p>
<p>* option 3 is likely to take longer to produce results than
option 2.</p>
<p>I say this after having worked a few years ago for a manufacturer
of ventilators and would point out "production lines" did not
really exist for that company. Ventilators are simply not
mass-produced as cars are. If you wanted to scale up production,
you simply needed more floor space filled with assembly benches
and basic electronic test equipment, and more workers to do
assembly and, above all, stringent testing. My guess is that the
critical factor in such a scale-up would be engineering staff with
the requisite QA and testing skills for medical devices (such
testing is not particularly easy or cheap to automate). That being
the case, one would not, IMHO, want them to be diverted to the
development of new designs.</p>
<p>And this is to take a first-world-centric view. Globally, the
real time bomb is in Africa. Slower spread of the disease in
Africa is, AFAI am aware, likely to be due to the demographic
profile (heavily skewed towards having young populations) and
possibly - just possibly - the effect of a warmer climate on virus
transmission. On the other hand, even in these conditions and with
the limited testing capability of most African states, it is clear
that the R number exceeds 1 and therefore that the number of
infections will grow exponentially and eventually overwhelm health
systems that have nowhere near first-world capabilities.The
worst-case effects of this in the near-coastal parts of the Sahel
are pretty ghastly (see the stats and maps in <i>New Scientist</i>
and <i>The </i><i>Economist</i>). Massive final excess-death
counts are far from impossible.</p>
<p>And while I'm on death counts, the current US death toll exceeds
95,000, which is greater than the total of US military deaths in
Korea and Vietnam combined. At this rate the number will easily
rise to 117,000, which exceeds the total of US military deaths in
WW1 - of which, ironically, more than half were due to Spanish
Flu!</p>
<p>Finally, after the above eclectic ramble, a simple
control-chart-like technique provides an insight into whether the
epidemic is coming under control. Plot a three-day moving average
of new cases against existing cases, both variates on logarithmic
scales. While the spread is exponential, this will give a straight
line. As the epidemic comes under control, new cases fall
precipitously below the straight line - as has been seen in China,
South Korea and, AFAI am aware Taiwan. There's a good video of
this on the <i>Vox</i> YouTube channel and I daresay someone more
adept at statistics than I am could turn this sort of thing into a
proper control chart with warning and confirmation limits.<br>
</p>
<p><br>
</p>
<p>regards,</p>
<p>Olwen</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 20/04/2020 10:23, Dewi Daniels
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CANQd8eU1yKe-6m3XtxZ=o1RVDNBsQmzLJFZqwJNSUYB5QjQM2A@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="ltr">I've only had a quick glance at the Twitter thread,
but I've read the government rebuttal.
<div><br>
</div>
<div>The FT article suggests that it was naive to try to develop
new designs and that it would have been better to focus on
manufacturing existing designs under licence. The government
rebuttal points out that the government's strategy focused on
three pillars:</div>
<div><br>
</div>
<div>1. procuring more devices from existing manufacturers
overseas</div>
<div>2. scaling up production of existing ventilator suppliers</div>
<div>3. working with industry to design and manufacture new
devices.</div>
<div><br>
</div>
<div>This three pillar approach seems very sensible to me.</div>
<div><br>
</div>
<div>I think the FT article underestimates the difficulty of
setting up a new production line to manufacture an existing
design under license. The intent of the third pillar is
presumably to design simple devices that serve a limited
purpose, but which can be manufactured quickly and cheaply.</div>
<div><br>
</div>
<div>If some of the suppliers chose to create simple, low cost
designs that satisfied the bare minimum function, and these
designs proved to be unsuitable, surely the fault lies with
the specification and not with the implementation? The FT
article seems to suggest that suppliers with experience of
medical devices would have known that the requirements were
incomplete. I think that greater care in specifying
the requirements would have avoided nugatory work.
Nevertheless, I don't think the problems with some of the
early designs invalidate the approach as claimed by the FT
article; rather, the specification should be updated, which is
exactly what's happened.</div>
</div>
</blockquote>
</body>
</html>