
What Is Suspension Trauma a.k.a. Harness Hang Syndrome? - mhb
https://www.dynamicrescue.com/blogs/news/13262417-ask-a-pro-what-is-suspension-trauma-aka-harness-hang-syndrome
======
yodon
A similar root cause issue is developing life threatening blood clots from
sitting too long. Both suspension trauma and blood clots in the legs come from
a clever optimization of our circulatory system. The heart can't actually pump
blood out of the legs. It counts on muscle activity to make the flow happen.

If you sit for many hours, like on a cross country or cross ocean flight, or
because you are a dev or gamer with tremendous concentration and focus, the
blood quite literally just sits in your legs and eventually starts to
coagulate. It doesn't matter how much exercise you get the rest of your day,
those 6 or 8 hours of sitting can quite literally kill you through the
creation of a blood clot that then flows through your system and blocks blood
flow to the heart or brain (all learned personally when I developed such a
clot from routinely sitting long hours in a coffee shop with my laptop and
100% focus).

If you're like me and can focus easily for many hours straight, get a Fitbit,
turn on activity tracking, and when it tells you you haven't walked around
recently get up and walk around. It's much less impactful to your
concentration than an emergency ER visit followed by a lifetime of
prescription blood thinners to reduce the now much higher risk of a second
clot.

~~~
z9tree
I also learned this the hard way after a 14 hour session of Diablo 3. I went
to the doctor a couple of times because my leg felt swolen and it was hurting
but they didn't think much of it for some reason - only after I developed
extreme difficulty breathing did I end up in the ER. The DVT had migrated from
my leg into my lungs and gave me a pulmonary embolism.

~~~
shrimp_emoji
What a terrible game to almost die for. I'm so sorry.

Also, 14 consecutive hours? Did you literally not get up at all in that
period? Did you have enough fluids and snacks nearby that you didn't have to?

~~~
z9tree
It was consecutive but I did get up from time to time for bathroom breaks, but
clearly not often enough. As for fluids I'm fairly sure I was pretty
dehydrated at the time. This occurred in 2015. Since this occurred and after I
learned from a nurse about the leg muscles being critical to get the blood
moving out of your legs I have developed a habit of constantly moving my legs
around any time they have not moved in a bit. When this episode happened I
remember that I would keep my legs very still during the gaming session.

------
newmac
I am currently building a house, and there are large portions of it that have
a >25ft drop from rooftop to the ground below. That means the workers on the
roof or upper floor need to wear proper fall protection. Depending on the job
that can often by a harness system.

I was surprised that because of the height of the potential fall, we needed a
"rescue plan". In other words: arresting the fall is only half the job.

The result was quite a bit of extra expense for us (because of the site
conditions, we need to keep a hydraulic lift available), but when I read about
how quickly suspension trauma becomes an issue, I could understand why the
safety regulations are written as they are.

~~~
Bartweiss
It's always surprising to me how fall risks operate in the world of OSHA
compared to rock climbing. There's an entire domain where people take good-
sized falls as an everyday event, just sort of sitting in parallel with the
domain where they're considered a major risk needing emergency-response
measures.

Obviously, some of that is a real difference in situation. Construction falls
are unplanned and happen under all sorts of odd circumstances, and people are
quite often injured during their falls. Climbers have someone managing the
other end of their rope at all times, on a system that makes lowering them to
the ground straightforward.

But other differences seem absolutely pointless. The "suspended by your groin,
legs hanging straight down" posture of construction harnesses massively
accelerates suspension trauma, while climbing harnesses pull the legs up and
keep pressure on large muscles. And there are companies starting to use that
design for safety gear, so it's not a regulatory issue - it just somehow took
decades to cross the gap.

~~~
takk309
I big difference between a climbing harness and a construction harness is the
tie in point. Climbing it is fine to have that point in front of the user. For
construction, having the rope constantly in front of you would be a real
inconvenience. By tying in on the back, the harness will hold the user in a
different orientation just due to the way weight is distributed.

~~~
Bartweiss
That's definitely part of it; climbing harnesses tend to support you in a
position that's great for suspension trauma, but involves a pretty
inconvenient rope. They're also waist-and-hip only, and while they'll reliably
hold a climber through a flip, it doesn't sound great for chaotic, confined-
space falls where you might _stay_ upside down.

The newer generation of construction harnesses are still back-clipped and
full-body though - a short strap runs from the waist to the back clip to
redistribute weight without normally being in front of you. Presumably getting
that working smoothly and safely was an extra engineering hurdle, but I'm
still surprised harnesses went so long without even including waistbands.

------
mindgam3
Wow, I had no idea this was a thing. I nearly blacked out the first (and only)
time I went skydiving. Tandem jump with instructor. Free fall was fun. After
parachute deployed the harness started feeling tight around my chest and legs.
I got dizzy and it felt like I was having a panic attack, difficulty getting
enough oxygen. When we landed I immediately fell to the ground where I
couldn’t get up for a few minutes.

My friends who jumped with me were all laughing and having a great time, they
thought I was being dramatic or something.

A web search brought up tons of hits of this being discussed in skydiving
forums. Apparently it’s related to older harnesses. Some skydivers don’t
believe it’s real.

Thanks for posting this.

------
QuotedForTruth
Its interesting to me as a rock climber that I've never heard of this. Its not
unusual for someone to hang in their harness at an anchor for quite a while
while their partner is climbing the pitch before and after. Are climbing
harnesses that much more comfortable than safety harnesses that its not a
problem?

~~~
JshWright
Are you typically hanging with all your weight in the harness, or are you
leaning off the wall?

~~~
Bartweiss
Interestingly - all your weight is on the harness, but the wall is still what
makes the difference. Suspension trauma is basically a bloodflow issue, so
resting against a wall lets you keep your feet elevated and your quads active,
stopping blood from pooling. The catastrophic case for suspension trauma is
hanging limp and unconscious, since it lowers your feet while stopping muscle
use or even fidgeting to boost circulation.

~~~
JshWright
The vast majority of your weight is in the harness, but there is some portion
of the force vector that's going into the wall as well.

But you're right, the weight distribution isn't really what matters in this
case.

------
hprotagonist
Whenever i'm climbing outside i have a few lengths of dyneema or cordelette
that i can rig into a prussick or kleinheist for self-rescue or for staying
comfy at multipitch belays that don't have nice ledges.

I don't hangdog all that much, so i was actually unaware of this risk, but
it's worth keeping in mind!

~~~
oftenwrong
Dyneema is not the best choice for friction hitches due to its low melting
point. This is primarily a concern when using it as a backup for abseiling or
lowering, or in any situation where you may take a fall onto the friction
hitch.

~~~
hprotagonist
I know. I don't use it for raps, but it's just fine as a static or static-ish
anchor.

------
reubenmorais
Last time I went skydiving I experienced something like this. I was doing a
pair jump and you do it in a harness that’s attached to the skydiver with the
parachute. When the chute opens you slide down/into the harness and it
compresses around your thighs. The first time I jumped, the instructor told me
to step on his feet so he could put some slack in the harness, but this time
the instructor didn’t do that, so for the whole time between opening the chute
and landing I was stuck motionless in the tight harness. I almost passed out,
it was pretty scary.

------
quacked
About a year ago, I was flying a hang glider and accidentally had a parachute
deployment, and I ended up suspended in a tree, waiting for a grounds crew to
come cut me down. The first thing that my friend said when I called him was
"stand up if you can". Suspension trauma is a real risk for pilots who get
stuck in trees, and it's a subject covered during parachute education clinics
for that reason.

------
I_complete_me
Coincidence or what? I attended a Safety Course (Construction) this very day
and was introduced to the term orthostatic trauma which is also called
suspension trauma. It so happens that I also do tree climbing with ropes and
am familiar with prusik knots for ascension. Everyone should experience the
sensation of climbing a single rope - it is magic. And finally I suffered
bilateral pulmonory embolisms that I am putting down to excessive sitting
while developing. My consultant told me that "20% don't make it to hospital"!
Chilling memories. This article struck me thrice.

------
BXLE_1-1-BitIs1
A climber can reach the rope, put in a prussik and stand on it. No can do with
construction harnesses. The rope's out of reach.

~~~
ken
There are products available which enable one to self-rescue from a lanyard at
your dorsal.

------
grahamburger
Interesting to see this pop up here! I'm in the process right now of getting
my team Tower Safety Certified by Comtrain and this is one of the things they
learn about. They also have to practice both being rescued from a tower (while
hanging limp as though they were unconscious) and rescuing someone else from a
tower. Gotta stay safe out there!

~~~
velosol
Given the address in your profile I'd suggest you might also want to have your
team have access to non-cell communications. Sometimes you're at a tower that
doesn't have great cell reception and even if the team is able to rescue an
injured member they won't be able to safely transport them and be stuck
sending someone to find cell coverage and call for an ambulance.

~~~
grahamburger
That's very true! Fortunately in our case (at least with the company I work
for currently) we don't do any work outside of cell coverage or more than a
few miles from a hospital. Part of the tower safety process though is to
decide before climbing the tower where you will take someone if they get
injured and how you'll get them them, or who/how you'll call if they can't be
transported.

------
bitL
Is this somehow related to feeling uneasy from skydiving once parachute is
deployed as well? I sometimes feel like I am going to pass out. I had a scary
situation while practicing multiple tailspins and free-falls on a sailplane
and almost blacked out after the last one (basically couldn't feel anything
and landed just by vision and mechanical yoke movements I couldn't feel at
all.

------
aasasd
> _as you inhale, the mediastinal intrapleural pressure becomes more negative,
> leading to expansion of the lungs, and pressure drops in the RA, RV, SVC,
> and IVC. Right Atrial expansion increases the pressure gradient for venous
> return_

So you're saying my lung volume has implications for the chance of deep vein
thrombosis or possibly even for varicose veins? Great engineering right there.

------
DoctorMemory
I started looking into a suspension system for Virtual Reality to increase
immersion. I thought it was surprising that no one had made a harness type
device. Then I came across suspension trauma and realized how complex an issue
it would be to make something like that and take it public.

------
dangerboysteve
This happens also to hunters that fall from hunting in tree stands and are
wearing a safety harness.

------
amelius
This is the stuff I think about when I find myself in an overly tight airline
seat.

~~~
brandon272
I am constantly and intentionally contracting my leg muscles when in an
airplane. Mainly due to comfort issues, but I figure it is probably also
helping blood flow.

------
leoc
Yeah, interesting timing. It also seems quite similar to the effect of high
(downward) G-forces.

