
Parachute use to prevent death jumping from aircraft: random controlled trial (2018) - ceejayoz
https://www.bmj.com/content/363/bmj.k5094
======
dang
[https://news.ycombinator.com/item?id=18677508](https://news.ycombinator.com/item?id=18677508)

[https://news.ycombinator.com/item?id=4644463](https://news.ycombinator.com/item?id=4644463)

~~~
Reelin
Why is this marked as a dupe now? It doesn't appear to have made the front
page since December 2018.

~~~
dang
The rule is "the last year or so":
[https://news.ycombinator.com/newsfaq.html](https://news.ycombinator.com/newsfaq.html).
The "or so" is there to stretch the dupe window for fluffier, more predictable
articles, particularly anything memey.

Conversely, we shrink it for particularly substantive and unpredictable
submissions, especially if they didn't get huge attention in the past, which
is partly what keeps them unpredictable.

Edit: here's a great example of that:

[https://news.ycombinator.com/item?id=22785015](https://news.ycombinator.com/item?id=22785015)

[https://news.ycombinator.com/item?id=22788542](https://news.ycombinator.com/item?id=22788542)

------
fmjrey
Reminds me of the recent interview of Pr Raoult who's been using chloroquine
to treat covid-19 in France. Here's a google translated extract:

To those who say that we need thirty multicenter studies and a thousand
patients included, I answer that if we were to apply the rules of current
methodologists, we would have to redo a study on the interest of the
parachute. Take 100 people, half with parachutes and the other without and
count the dead at the end to see what is most effective. When you have a
treatment that works against zero other treatment available, this treatment
should become the benchmark. And it's my freedom to prescribe as a doctor. We
don't have to obey government orders to treat the sick. The recommendations of
the High Health Authority are an indication, but it does not oblige you. Since
Hippocrates, the doctor has done for the best, in the state of his knowledge
and in the state of science.

[https://translate.google.com/translate?sl=fr&tl=en&u=https%3...](https://translate.google.com/translate?sl=fr&tl=en&u=https%3A%2F%2Fwww.upr.fr%2Factualite%2Fpour-
comprendre-les-enjeux-du-traitement-du-coronavirus-par-la-chloroquine-nous-
vous-conseillons-de-lire-lentretien-du-professeur-raoult-dans-le-parisien-
du-22-mars-2020%2F)

~~~
ceejayoz
There's reason to be skeptical of him.

[https://en.wikipedia.org/wiki/Didier_Raoult#Ban_from_publish...](https://en.wikipedia.org/wiki/Didier_Raoult#Ban_from_publishing_in_the_American_Society_for_Microbiology)

> In 2006, Raoult and four other co-authors were banned for one year from
> publishing in the journals of the American Society for Microbiology, after a
> reviewer for Infection and Immunity discovered that two images in a figure
> from the revised manuscript of a paper about mouse modelling for typhus were
> identical to figures from the originally submitted manuscript, even though
> they were supposed to represent a different experiment.

~~~
fmjrey
There are reasons to be skeptical of everyone!

~~~
Reelin
The reasons are particularly relevant in this case.

[https://blogs.sciencemag.org/pipeline/archives/2020/03/29/mo...](https://blogs.sciencemag.org/pipeline/archives/2020/03/29/more-
on-cloroquine-azithromycin-and-on-dr-raoult)

[https://science.sciencemag.org/content/335/6072/1033](https://science.sciencemag.org/content/335/6072/1033)

~~~
fmjrey
Again people not on the front line criticise those who are.

If you get infected, would you take it, or would you wait and see the result
of the full study?

Now imagine having to take that decision not just for your life, but for your
patients, and all the 200 staff that work in your hospital.

Another way to view the situation: you are a policeman stopping an ambulance
not respecting the driving code and driving too fast, and then learn there is
a dying patient in the back, what do you do?

~~~
yellowapple
> Another way to view the situation: you are a policeman stopping an ambulance
> not respecting the driving code and driving too fast, and then learn there
> is a dying patient in the back, what do you do?

Tell the ambulance driver to turn on the siren and party lights and have a
nice day.

Like, there are already exemptions for ambulances driving "recklessly" as long
as they're indicating (via siren and lights) that they're doing so in an
emergency situation.

On that note, though, if the ambulance is driving _too_ recklessly it might do
more harm than good to the patient. It wouldn't necessarily be the police
officer's place to make that determination, but it could certainly be a
contributing factor for reprimanding the ambulance driver should the patient
end up more injuries coming out of the ambulance than one did getting in.

Overall, a pretty poor analogy IMO, even if I do (to an extent) agree with
your point.

------
ninetax
Haha, I love this. Here's the real point of the paper IMO:

> Conclusions Parachute use did not reduce death or major traumatic injury
> when jumping from aircraft in the first randomized evaluation of this
> intervention. However, the trial was only able to enroll participants on
> small stationary aircraft on the ground, suggesting cautious extrapolation
> to high altitude jumps. _When beliefs regarding the effectiveness of an
> intervention exist in the community, randomized trials might selectively
> enroll individuals with a lower perceived likelihood of benefit, thus
> diminishing the applicability of the results to clinical practice._

I wonder what else that's applicable to?

------
Reelin
This article about the paper is likely to be more informative than the paper
itself. ([https://blogs.bmj.com/bmj/2018/12/13/we-jumped-from-
planes-w...](https://blogs.bmj.com/bmj/2018/12/13/we-jumped-from-planes-
without-parachutes-and-lived-to-tell-the-tale/))

The study is an absolutely ingenious way of simultaneously illustrating
multiple different challenges that can frustrate randomized controlled
clinical trials. Some highlights:

> We believe that randomisation is critical to evaluating the benefits and
> harms of the vast majority of modern therapies, most of which are unlikely
> to be nearly as effective at achieving their end goal as parachutes are at
> preventing injury among people jumping from aircraft.

> RCTs are vulnerable to pre-existing beliefs about standard of care, whether
> or not these beliefs are justified

> When strong beliefs about the standard of care exist in the community, often
> only low risk patients are enrolled in a trial, which can unsalvageably bias
> the results, akin to jumping from an aircraft without a parachute.

> even a well conducted RCT can provide misleading results

------
6502nerdface
It appears to be a reply to this 2003 paper in the same journal:

> Parachute use to prevent death and major trauma related to gravitational
> challenge: systematic review of randomised controlled trials [1]

[1]
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300808/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300808/)

------
amelius
The problem with most commercial aircraft is you can't reach the door in time.

Hence I use an airbag suit.

------
throw0101a
Alternatively you can put the parachute on the aircraft:

* [https://en.wikipedia.org/wiki/Cirrus_Airframe_Parachute_Syst...](https://en.wikipedia.org/wiki/Cirrus_Airframe_Parachute_System)

------
Fjolsvith
Man, I'd hate to get the placebo.

~~~
detaro
> _Compared with individuals screened but not enrolled, participants included
> in the study were on aircraft at significantly lower altitude (mean of 0.6 m
> for participants v mean of 9146 m for non-participants; P <0.001) and lower
> velocity (mean of 0 km/h v mean of 800 km/h; P<0.001)._

You'd be fine ;)

~~~
yread
Every year lots of airline and airport workers get injured or die falling from
a stationary aircraft when mobile stairs fail or are retracted too early. On
the other hand parachute wouldn't help them either

~~~
detaro
that's also slightly different than jumping down 2 feet.

------
kgc
This study seems like a waste of time. People jumped from a stationary
aircraft on the ground.

~~~
detaro
That's the point: [https://blogs.bmj.com/bmj/2018/12/13/we-jumped-from-
planes-w...](https://blogs.bmj.com/bmj/2018/12/13/we-jumped-from-planes-
without-parachutes-and-lived-to-tell-the-tale/)

------
dhosek
I kept looking at the site to find some indication that this is satire. As
near as I can tell, this was a legit study. I'm genuinely perplexed.

Edit: Silly me. It turns out that while BMJ is a legit journal, the study
itself is satire and does identify itself as such near the end and via a
linked opinion.

~~~
xboxnolifes
The best kind of satire is the kind that goes all the way. This is what you
get if nobody tries to accept new information without a "double blind randomly
controlled trial" for it.

~~~
asdfasgasdgasdg
If this is meant to be salient to the current situation e.g. with
hydroxychloroquine, I'm afraid it has missed the mark by a long distance. In
Bayesian terms, the prior for parachutes helping when falling from great
heights is extremely strong. It would take extraordinarily strong evidence to
dissuade us from the idea that they are effective, given our prior knowledge
of physics and the effect of high velocity collisions on the human body. The
priors for a particular immunosuppressant being effective against a particular
virus are not nearly so strong.

Fortunately, some folks are doing actually high quality research on this right
now, so we should have more solid evidence on this topic soon.

~~~
ceejayoz
> Published 13 December 2018

It probably has nothing to do with the current situation, barring a time
machine, which should probably get its _own_ article.

~~~
asdfasgasdgasdg
I know the published study has nothing to do with the current situation. I'm
referring to the motivation for posting/upvoting/commenting on it right now.
For context, there is a significant push in the online COVID discussion space
for discarding rational methods when evaluating potential COVID treatments.
I've seen comments in this direction both here and on Reddit. That's the only
reason I brought it up.

For anyone just upvoting or discussing this because they thought it was funny
or interesting, more power to them.

~~~
ceejayoz
My motivation in posting it was that I stumbled across it and found it funny.

~~~
asdfasgasdgasdg
Awesome! Again, my comment is not directed at any particular person. It's
directed at a particular motive. If you don't have that motive, my comment
isn't talking about you and you can feel free to ignore it if it doesn't bring
value into your life. :)

