Suspension Trauma can be applicable to anyone who
is left suspended for short or long periods of time,
be it for work or pleasure circumstances. For further
information please read on.
Suspension trauma, or orthostatic intolerance,
is a natural human reaction to being upright and immobile,
where blood pools in the legs leading to unconsciousness.
It can be caused by suspension in a harness (deliberate
or accidental), when trapped in a confined space, when
secured to a vertical stretcher or litter - any situation
where you are forced to stay upright without standing.
If it is allowed to develop unchecked, it will be fatal.
This website provides free, impartial advice on how
to deal with the risks of suspension trauma, both at
work and at play. It also gives in-depth guidance for
medical staff and first responders, as it is not part
of the normal first aid, EMT or paramedic training in
You may link to us, quote, extract or print anything
from this site provided you leave the copyright visible.
What is suspension trauma?
Suspension trauma is a perfectly natural reaction caused
by the body being held in an upright position. It will
happen to everyone, and you do not need to be ill or injured
- simply standing still and unable to fall over.
Our blood supply and heart cannot cope very well with
standing up - gravity pulls blood into the tissues of
our legs, and the heart cannot suck it back. Eventually,
if enough blood pools in the legs, we will faint. This
is fine, so long as we fall over - the blood all rushes
back - but if we can't fall over, then we die.
Of course we can stand and walk about in normal life and
not risk death, and this is because our leg muscles can
pump the blood back upwards, provided you are able to
move your legs. When we walk about, this works very well.
Standing still it's less effective, and sometimes we faint.
If we can't use our legs at all, such as if we're strapped
into something or hanging in a harness, then we will faint.
The problem comes after that - if you faint, you really
need to fall over right away. Stay in the same position,
and your brain has no oxygen supply.
Who does it affect?
Anyone who could faint and not fall over. People
working in industrial harnesses (using abseiling or
fall arrest systems or people in confined space shafts),
people using harnesses for sport (caving, climbing,
parachuting, parascending, bungee jumping) and people
using harnesses for special tasks (stuntmen, theatrical
flying, etc) are all exposing themselves to high risk,
some more than others. Anyone who is secured to a vertical
surface for any reason (a rescue litter or spine board,
plank of wood, door, bondage equipment, etc) may also
be at risk. The most famous, or infamous, example of
deliberate suspension trauma is of course nailing someone
to a cross.
In any of these situations if you are not using your legs
for support, or are unable to move them, then you will
eventually faint. If you live or die depends simply on
how quickly you fall over - preventing that from happening
will of course kill you.
What exactly happens?
First, let's look at blood, and where you can put it.
Your body contains about ten pints of blood, most within
your veins and arteries. Think of these like stockings
- they will stretch a lot if you keep pushing more into
them, so to fill them to the top you need to squeeze the
outsides. Tiny muscles do that to our veins, a process
called 'tone'. If these muscles relax a little, then all
your blood pours down under gravity, and at the extreme
it will all fit below your waist. Naturally this isn't
a daily event, but keeping the blood from pooling in your
legs is actually a difficult problem. Gravity is strong,
and blood is dense, so to suck it back up the four or
five feet from your legs to your head would be very hard
work - you certainly couldn't do it yourself with a length
of tube! Your heart is the pump, and it can't suck that
hard. In fact it can't suck at all - it needs blood to
be pumped IN under pressure or it just beats on empty.
Now to get that blood back up from our feet, we
could increase the pressure - forcing it round like a
blockage in a U-bend - but that would need such high pressure
our hips would burst. No, instead of turning up the power,
we have evolved a much better solution - hearts in our
legs. Yes, you read that right. The veins in our legs
already have one-way valves in them, so all we need is
to squeeze them and we've got ourselves a pump! Since
we started walking upright, these leg veins have moved
so they are buried in between the muscles, so as we move
our legs and walk about, the veins are squashed and released
over and over - pumping the blood back up into your abdomen.
It's an amazingly good system - when you're running, there's
hardly any blood pressure in your feet at all!
Of course you can see the error with this perfect plan
- if you don't use those muscles the pumping effect stops
and your brain, right at the top of the pile, runs dangerously
low on blood very quickly! This can happen if you're standing
very still, or hanging in mid-air, or strapped to something.
If you're standing still then the brain can fix the problem...
Firstly, when blood to the brain reduces, your
brain decides to put you in shock. You must be bleeding
somewhere, right? So, it increases your pulse and breathing
rates, you feel a little sick, shivery, cold, sweaty and
anxious. This doesn't really help much, as what you SHOULD
be feeling is a craving for exercise - but never mind,
evolution is never perfect. That higher pulse rate shunts
blood up to the brain and away from the skin, which helps
for a few minutes - but of course it's still pumping blood
down into those legs as well.
Eventually, your brain
realizes its mistake and goes for plan B - the Central
Ischemic Response. You faint.
Why? Because of course if you faint, you must fall
over. Your brain has learnt that from millions of years
of... falling over. When you hit the floor, the blood
trapped in your legs returns, and all is well. You wake
up, feel sick, and if you're a soldier on the parade ground
you prepare for the punishment of your life. The problem
is when you don't fall over. Your brain has no comprehension
of that idea - so if you are physically held upright after
you've fainted - by a harness, litter or cross - your
brain is in deep trouble. It's turned off its own blood
supply to get you to faint, and it still needs the blood
in your legs. So, it waits. You're unconscious of course,
so you aren't aware of all this... but you wait. You do
not 'wake up and try something else' - you wait. You die
How long have you got?
If your legs are perfectly still, then you can start feeling
the first signs of shock in as little as three minutes.
The average is between five and twenty minutes. You will
faint a few minutes after that, and if you are not allowed
to lie down straight away then your brain can start to
die a few minutes later.
So, worst case scenario you can be dead in ten minutes.
Actually, less than that - because once you faint, you
lose control of your airway and if your body is upright
you can choke on your tongue and suffocate in a matter
Not everyone will be pushing death inside of a quarter
hour though - the time it takes is random. Some people
will last ten, some sixty. Age, height, weight, fitness,
sex, race - none make any difference. The same person
will react differently from one day to the next. In short,
it's unpredictable. Very old people suffer first, as their
muscles are less able to control the blood flow, and very
young children are immune as their bodies are just too
short! Nobody's sure at what age you become 'at risk',
but certainly anyone over about 5 feet tall is capable
of feeling the effects.
Preventing suspension trauma
Without being too obvious, the best way to prevent
suspension trauma is never to get into a position where
it can start! Working with harnesses is perfectly OK,
provided you PLAN to prevent suspension trauma. The same
goes for medics and rescuers using litters, and for those
who enjoy tying each other up.
Assuming you've read the Introduction you'll know
how and why the condition develops, and that it's all
started by blood pooling in your legs. If you are going
to be in an upright position for more than five or ten
minutes, then you will be at risk. A rock climber is safe
because he or she is using their legs all the time - but
if they fall off, stop for lunch, or just get bored and
'dangle', then it's a different matter.
Preventing suspension trauma can take one of two approaches
- either we stop the blood pooling in the first place,
or we make sure it's pumped back out. Which you choose
depends on what you're doing, and it is very important
indeed that you pick the right method. Some sources of
advice, even some government publications, get this bit
very wrong and you could end up very dead if you follow
Plan 1: Sitting up, chilling out
You're probably sitting in a chair reading this. You haven't
moved your legs in a while, but you're not dead. It's
all down to the fact your thighs are almost horizontal
- they are where most of the blood pools, and so if they
are kept elevated then suspension trauma is almost impossible.
Think of how many times you've heard of someone fainting
to death in an armchair.
For anyone suspended in a harness and who doesn't need
to move about all the time, or who can't (for example
someone who has fallen and is injured, tired or just lazy)
then the best, most effective and easiest way to keep
them safe is to lift them into a sitting position. Looping
something under their knees, or sitting them on a swing-seat,
is all you need to do - the person can often do that themselves
if they've got something to hand. It's very important
to do this as soon as possible - within a few minutes
of suspension - so the blood has no time to begin pooling.
If you know you're going to be suspended for a while,
like an abseiler cleaning windows on a skyscraper, then
you can take a seat with you. If you're tying someone
up, think carefully about the position of their legs.
If you're about to winch someone down a lift shaft in
a rescue litter, then don't!
The trick is to lift the knees and to use your legs as
little as possible - the more you use them the more blood
is sent down to the muscles. Sit down, relax, and chill
Plan 2: Invisible Bicycles
Just as with the rock climber, or you when walking to
the kitchen, using your legs keeps the blood flowing.
Even hanging in a harness, if you are using your legs
to climb about, you will be safe. The problem comes when
you're in mid-air, or you're injured or tired, and that
movement is a bit less forceful. Now, the pumping effect
is reduced but your leg muscles are exercising, so they
need blood! The arteries feeding your legs open wide,
blood pours into your legs, and eventually... well you
can see the result. The 'keep your legs active' plan works
great if you have surfaces to kick against, like our rock
climber. It's useless for anyone who physically cannot
move (strapped into something, or injured), and once you
start madly pedalling that invisible bicycle in mid-air,
you know that you cannot stop. If you do, the blood rushing
into your legs stays there, and the world goes dark around
So, what have we learnt so far?
- Unless you're planning on moving about for some
other reason, lifting your legs into a sitting position
is the best plan, and the easiest.
- Try to avoid being 'upright and immobile' for more
than a few minutes at a time, and if you feel ill,
get out of the position straight away!
- Never leave anyone alone who may be at risk of
Suspension trauma treatment
Treating someone with suspension trauma is not standard
First Aid. If you follow the normal advice for 'fainting'
then you can easily kill your patient. If you haven't
read our section on Reflow Syndrome then please
do so now.
Anyone who has developed suspension trauma to any
extent will have reduced blood flow to their brain.
This initially causes symptoms of shock, and if
untreated will lead to loss of consciousness. This
in itself could kill by preventing the patient controlling
their own airway, but eventually the reduced cerebral
blood supply will lead to brain damage and death.
The goal of the first responder is to return oxygen
to the brain while preventing Reflow Syndrome. Never
allow the patient to lie down, even for an instant
Normally; suspension trauma makes the legs feel
numb. If the patient has no other injuries and yet
complains of severe pain in their legs, especially
when you try to move them, then they may have developed
a severe condition called compartment syndrome.
You should place them in a sitting position and
summon an ambulance with great urgency. The patient
may deteriorate rapidly. There is nothing you can
do for compartment syndrome as a first responder.
If the patient is conscious
Your first action should be to place the patient
in a sitting position with their body upright and
their legs flat. This will reduce the pooling effect
of gravity, but will keep most of the pooled blood
in the legs, preventing reflow. The patient must
not be allowed to stand up, exercise, drink or eat.
If possible keep them as calm and relaxed as you
can, to reduce the effects of stress on the heart
Obviously they need to be removed from suspension,
and kept in the same sitting position at all times.
They may feel faint, and so you will have to stay
with them and prevent them collapsing onto the floor.
If you have oxygen available, administer it at 100%.
Do not give the patient any other medication or
fluids. Summon medical help as soon as possible
- a fully conscious and aware patient may be taken
to hospital in a private vehicle, but remember that
everyone suspended for more than a few minutes should
be sent to hospital for routine blood tests, even
if they are not injured.
If you cannot reposition the patient or remove them
from suspension, then you must expect them to faint
at some point. Providing oxygen will help a great
deal, but your priority is maintaining their airway
and arranging urgent rescue.
If the patient is unconscious
Loss of consciousness due to suspension trauma itself
indicates that the pooled blood has had time to
develop, and that laying the patient flat will probably
be counterproductive - even leading to death. You
will have to manage the airway while keeping the
patient in a sitting position. Suspension trauma
rarely leads to cardio respiratory arrest in the
short term, but if the patient requires CPR then
this overrules the posture policy, and you must
of course lay them flat. A patient who has been
rendered unconscious by another event (such as impact
in a fall or electrocution) and who is reached within
the first 10 to 20 minutes of suspension may be
allowed to lay flat. If you are trained in the use
of artificial airways (such as the NPA) then these
may assist in supporting the airway even in a sitting
EMT / Paramedical PHLS treatment
Note that suspension trauma (orthostatic incompetence)
is not part of your standard training program. You
should approach the incident as similar to a crush
injury in terms of immediate management though there
are critical differences in both pre-release and
post-release therapy. If the condition is advanced
or the patient has lost consciousness, urgent transport
to a trauma centre is required.
The patient will be cerebrally hypoxic due to gravitational
pooling of venous blood in the legs, the majority
being in the thighs. The initial presentation after
5 to 10 minutes of suspension will be of distributative
shock leading to tachycardia and tachypnea. Local
PP02 from fingertip sensors will be normal, but
saturations from earlobe sensors will be reduced.
There need be no other injuries. The patient may
complain of general symptoms of shock, heat or absence
of sensation in the legs. Patients reporting severe
pain in the legs with the absence of orthopaedic
insult are of great concern as it suggests formation
of compartment syndrome.
As soon as possible after suspension has begun,
the patient should have been repositioned into a
sitting posture with the thighs horizontal or elevated
with respect to the pelvis, and the spinal column
vertical. If this was done within a few minutes,
then it is unlikely that a sufficient volume of
blood has pooled to cause loss of consciousness;
however it will still present a hazard if permitted
to reflow. A patient who has not been repositioned
in time is likely to have progressed beyond distributative
shock and lost consciousness via the central ischemic
response. Barometric trigger pathways will produce
enforced syncope via bradycardia, leading to decreased
cerebral perfusion and instant LOC. If the patient
falls into a prone position at LOC then blood returns
to the brain and they recover without artefact,
however in suspension the patient is usually unable
to fall over, and remains held upright. In this
position the LOC persists, as does bradycardia and
almost negligible cerebral perfusion. This is in
itself fatal within a matter of minutes, but of
course the patient is also unable to maintain a
patent airway and often will suffocate.
Stabilisation is possible on scene, but great care
should be taken to monitor PP02 and HR during release
and transport, as the patient will be electrocardially
- Do NOT allow the patient to lie flat or stand
- Provide oxygen at 100% for all patients
- Manually stabilise the airway via all possible
means, but do not lie the patient flat
- Minimise fluids to those required for unrelated
trauma. The patient is not hypovolemic and adding
IV will lead to hypervolemia when the patient is
repositioned. You may start a keep-open line for
future access but operate on minimal flow
- The patient may also be hypothermic if suspended
outdoors, and external rewarming may be necessary.
Do NOT give warmed IV fluids at this stage.
- Monitor ECG carefully - peaked T waves, prolonged
QRS or HTN indicates hyperkalemia and the onset
of crush syndrome. If detected, direct and aggressive
action is needed. This is beyond current PHTLS training
but via direction will require IV bicarbonate, calcium
chloride, albuterol or insulin via large-bore IVs
running normal saline. This contradicts the earlier
fluid restriction policy but is only to be initiated
if ECG artefacts' are identified.
- Transport the patient, in the sitting position,
to the nearest hospital
Hospital ER treatment
If the patient has been in suspension for a prolonged
period (variable, but between 5 and 40 minutes is
normal) then venous pooling in the legs will have
lead to cerebral hypo perfusion and hypoxia. This
may have been treated on scene with O2 or by repositioning
into a sitting posture. DO NOT ALLOW THE PATIENT
TO LAY FLAT for at least 30 minutes. Pooled
blood has been static for some time, and will be
entirely hypoxic. Anaerobic metabolism within the
legs will result in toxic levels of metabolites
in the pooled volume, and on release into flow the
pooled blood can result in cardiac arrest, dramatic
ETCO2 and PP02 fluctuations and transient hypercarbia.
Cytochrome-C release and transient renal hypoxia
will result in renal artery spasm, tubular necrosis
and potential acute renal failure within 60 to 80
hours of the incident. Increased serum certainine
with reduced output, uraemia and acidosis are diagnostic.
Dialysis would be required to prevent mortality.
In most cases of suspension in a purpose-designed
harness, confined space or litter then the patient
will not have experienced insult sufficient to cause
crush syndrome, however extended suspensions (in
excess of 2 hours) or those with thin ropes or straps
may initiate the syndrome. It manifests as release
of potassium and myoglobin, and can contribute to
renal insult. Serum K should be monitored, as hyperkalemia
is diagnostic in these cases. Treatment of crush
syndrome is based on volumetric support, renal protection
and serum K management. Once local reflow has been
corrected then IV support may be required to manage
hypovolemia, bicarbonate and mannitol are indicated
to control acidosis and hyperkalemia. Monitor ECG
and regular urine myoglobin, CPK and full chem.
In severe cases of vertical immobile suspension
where pooled blood has become cytotoxic, a split-form
full blood transfusion is possible and effective,
with surgical interruption of the femoral arteries
and veins placing the lower limbs on bypass, enabling
a localised transfusion and management regime for
reflow and crush syndrome to be applied while the
remainder of the body is managed in isolation. If
successful this can remove the need for amputation,
though the procedure is complex.
Patients are considered equally susceptible to suspension
trauma in terms of gender, age, fitness, body mass
or race. Those taking tricyclic antidepressants
will have increased susceptibility as they contribute
to orthostatic hypotension. There is no difference
in treatment or medication required for patients
Training for those at risk
Clearly everyone at risk of suspension trauma should
be aware of what it is, how to prevent it and what
to do in an emergency. Typical user groups include:-
- Industrial climbers, abseilers, rope access
and fall arrest harness users
- Climbers, cavers, parachutists and parascenders
- Stunt professionals
- Theatrical and circus flying system operators
- Professional and amateur performance artists
and practitioners working with human suspension
- Mountain and cave rescue teams
- Military and special forces operatives using
abseil or helicopter access systems
In addition, those who may be called in to handle
a suspension incident need training in what medical
and rescue procedures to use, and importantly what
NOT to do. They should be aware of the information
on our treatment pages and how to apply it safely.
Normal First Aid, EMT and even paramedic training
does not include suspension trauma, and what they
know about 'fainting' can be dangerous as they will
want to lay the patient flat. It is often up to
the worker or his colleagues to advise medical staff
as to what to do.
At-risk users should plan their work with suspension
trauma in mind. Trying to avoid it in the first
place is all-important, and so people planning jobs
need to be mindful of the risks of accidents, how
and when a worker could be placed in suspension,
and how long it will take for them to be rescued.
The critical things for workers to remember are:-
1. Hanging immobile
in suspension is a life-threatening emergency
2. You must never work
in suspension unless you are sitting on a work seat
or actively using your legs
3. If someone falls
into suspension and cannot be rescued, lifting their
knees into a sitting position is very important
and may save their life
4. When rescuing someone,
avoid them laying flat on the ground. Keep them
sitting up for 30 minutes
all this to the emergency services, paramedics or
hospital doctors - most will not know it
If you are working in the EU, then your national
version of the EU Temporary Work at Height Directive
makes it law that you plan for, and educate your
workers in, the risks of suspension trauma. You
also have to have effective and fully trained rescue
plans and equipment in place for all work.