Suspension Trauma

[Bob Mehew]

In a scan of the past 20 plus years of BCRC records there were some 16 incidents who causes included "hung up".

 

[andrewmcleod]

There aren't many call-outs for Devon Cave Rescue, but there was one last night. Not on their web site yet, but on their Facebook page: 2 people trapped in an abandoned mine in East Cornwall ... one trapped by being stuck in suspension on the ropes. ...The patient was exhausted and suffering from injuries due to being held in suspension for a significant amount of time.

Technically I think it was an East Cornwall SRT team callout (as both the Cornwall teams do both hill and underground rescue) with Devon Cave Rescue and the HART team assisting. But same difference

 

[Maisie Syntax]

With my medical hat on (Cave Rescue doctor for ~20 years)

Suspension syndrome/trauma and crush injury are 2 very different conditions. They are often taught together, which is not helpful, as while they may appear similar, the underlying pathology and treatment is quite different

Suspension trauma is principally thought to be due to the pooling of blood in the legs in a vertically suspended non-moving causalty. Return of the blood to the heart requires muscle activity in the legs to compress the veins, so if there is no muscle activity, the blood will not flow back. Eventually, this will lead to an inability of the heart to deliver enough blood to the rest of the body. When that starts affecting the brain, the casualty will start to pass out/faint, and the issue with being suspended is that you then can't go to a horizontal position. If you remain vertical, the inadequate flow of blood to the brain will start causing severe harm, and potentially be lethal. Getting the casualty into a horizontal postion should help equilbrate the pressure in the blood vessels, allowing blood flow to return to the brain and other vital organs. In surgery, we often cut blood flow off to a leg (e.g. knee replacements) or the whole lower body (operations on the aorta) for up to 90 mins, before reperfusing them. The time for oxygen starvation to start causing irreversible brain damage is much less, so the worry about toxins building up in the legs is not really relevant here - by the time that may have happened, they will almost certainly be dead from oxygen starvation to the brain. Using a tourniquet will not help, but has the potential to cause severe harm, such as loss of a limb.
In addition, it will probably be hard to get specific post-mortem findings if someone dies of suspension trauma, especially as the reason they are immobile is probably also contributory (hypothermia, injury etc). Experimentally, people have started getting symptomatic after only a few minutes, but there is certainly variability between people, although the exact reasoning isn't clear. Either way, the key point is that passive suspension is potentially dangerous, and someone incapacitated on a rope should be got down as soon as possible, or positioned horizontally if they can't be got down. Once down they should be positioned flat/recovery position if unconscious. The W position (knees up, sat up) has no evidence to support it, and is not recommended. As for a conscious casualty - if they have remained conscious throughout then they have not had full suspension syndrome, but potential pre-syncope (near fainting). It would be prudent to have a period of time recovering before mobilising again, but the majority of the guidance is written for people with full suspension trauma; i.e. unconscious. The HSE document remains a good resource (I accessed it at https://www.hse.gov.uk/Research/rrpdf/rr708.pdf)

Crush injury results from direct muscle damage from high or persistant pressure applied to cells, resulting in cell death and the release of cell breakdown products. There is a possible role for tourniquets, but more to control any catastrophic bleeding on releasing the pressure. For example, if your femur has been shattered by a boulder, it is quite possible bits of bone have ripped one of the major arteries, which is then compressed. When the boulder is removed, the artery is no longer compressed and it might get a bit bleedy very quickly. Tourniquets can be very useful to stop catastrophic bleeding, but the role in preventing backflow of toxins into the body is significantly less clear and they are not currently recommended for this.

My medical advice would be to avoid both of these conditions

Re crush injuries: Having been involved at the sharp end of trying to recover the situation for the victims of a crush injuries, I suspect the example given relating to bleeding from arteries etc. could be a bit misleading?
In the many hundred examples of crush injury I've been involved with, actual haemorrhage from cut arteries/broken bones was hardly, if ever, the causal factor of the 'crush injury. Indeed, the bleeding out from an artery, whilst not welcome, could actually reduce the effects of a 'crush' injury.
Crush injuries involve the crushing of muscle and the subsequent release of toxins from from within the muscle cells (myoglobin, causing rhabdomyolysis), rather than just the outcome for someone having something heavy fall on them e.g. boulder choke.
The vast majority of patients with crush injuries we dealt with, often had little or no outward signs of trauma on initial admission. Classic examples are of someone who has had a stroke/CVA and collapsed immobile on the floor, or an IV drug user who has miscalculated their dose and collapsed unconscious to the floor - often within the cubicle of a public toilet (Yes, I'm aware of the cliche here) (NB see also 'compartment syndrome'). When a person lies totally immobile on the hard floor (post stroke) (or wedged against the wall of a toilet cubicle and the rim of the toilet bowl), the blood supply to the muscle(s) can be cut off, with the subsequent lack of oxygen to the muscle cells, leading to death of muscle tissue and, ultimately, the likely release of intercellular contents of dead muscle tissue being released into the circulatory system once the cause of the pressure preventing blood flow has been released (e.g. removed from wedged down the side of the toilet, or rolled over on the floor from the position they originally landed when they collapsed).
Whilst this may appear to be a somewhat pedantic diversion from suspension trauma, if the aim is to improve knowledge for those who may be involved in the rescue of someone with potential suspension trauma (or someone laying immobile after a fall), then it doesn't hurt for those people to be aware of other factors which, in the light of an ongoing rescue situation, it may be advantageous to be aware of.
The good news? - Rhabdomyolysis as a result of crush injury, can be resolved successfully, but may require surgical intervention and/or a period of renal replacement therapy in the form of dialysis.
For the record, in the years I was treating crush injuries, I never came across one caused by suspension trauma, although I recognise that this could be a predisposing factor in some situations and has been described in the literature.

 

[paul]

The issue with suspension trauma isn't being suspended for a period of time, it's being immobile while being suspended for a period of time.

 

[mikem]

& it shouldn't actually be called suspension trauma, as that is a remnant from when it was thought to be caused by toxins released back into the body from the (trapped) legs

 

[aricooperdavis]

& it shouldn't actually be called suspension trauma, as that is a remnant from when it was thought to be caused by toxins released back into the body from the (trapped) legs

I've been reliably informed that "suspension syndrome" or "suspension syncope", depending on what exactly is being described, is more commonly used by medics these days.

 

[mikem]

From webMD (causes also include dehydration):

Fainting, also called syncope (pronounced SIN-ko-pee), is a sudden, brief loss of consciousness and posture caused by decreased blood flow to the brain.

Many different conditions can cause fainting. These include heart problems such as irregular heartbeats, low blood sugar (hypoglycemia), anemia (a deficiency in healthy oxygen-carrying cells), and problems with how the nervous system regulates blood pressure. Some types of fainting seem to run in families.
...
You may have a simple fainting spell due to anxiety, fear, pain, intense emotional stress, hunger, or use of alcohol or drugs. Most people who have a simple fainting spell have no underlying heart or neurological (nerve or brain) problem.

Many of these have surely been involved in different real suspension incidents.

 

[kay]

"When a person lies totally immobile on the hard floor (post stroke) (or wedged against the wall of a toilet cubicle and the rim of the toilet bowl), the blood supply to the muscle(s) can be cut off, with the subsequent lack of oxygen to the muscle cells, leading to death of muscle tissue and, ultimately, the likely release of intercellular contents of dead muscle tissue being released into the circulatory system once the cause of the pressure preventing blood flow has been released (e.g. removed from wedged down the side of the toilet, or rolled over on the floor from the position they originally landed when they collapsed)."

Does this have any relevance to pressure sores?

 

[Maisie Syntax]

"When a person lies totally immobile on the hard floor (post stroke) (or wedged against the wall of a toilet cubicle and the rim of the toilet bowl), the blood supply to the muscle(s) can be cut off, with the subsequent lack of oxygen to the muscle cells, leading to death of muscle tissue and, ultimately, the likely release of intercellular contents of dead muscle tissue being released into the circulatory system once the cause of the pressure preventing blood flow has been released (e.g. removed from wedged down the side of the toilet, or rolled over on the floor from the position they originally landed when they collapsed)."

Does this have any relevance to pressure sores?

Same principle, in that damage is caused by lack of oxygenation to cellular tissue.
In the case of pressure sores, the lack of adequate perfusion of the various levels of skin/surface tissue can cause necrosis of tissue, leading to a pressure sore. Note that there are other causes of pressure sore, including 'shearing' type forces on the skin. Skin tissue can generally be restored by a series of processes which I'm not going in to here.
Crush syndrome/compartment syndrome is when blood flow to a muscle is reduced and maintained to the point where oxygenated blood can no longer supply the muscle tissue, causing damage/death of the tissue. Think of it as being a 'cardiac arrest' of whichever muscle is involved. Muscles are encased in sheaths of fascia (think sausage skin). If you can picture arterial/oxygenated blood flowing into the muscle, as it is meant to, but is then being prevented from leaving it by pressure from an external source, the muscle becomes congested with blood to the point that no further oxygenated blood can enter - resulting in the death of muscle tissue. The pressure on the muscle is also exacerbated by the high pressure of the arterial blood flow still trying to enter the muscle, but with no way out. In effect, the muscle is 'crushed' from within by the blood being constrained by the fascia encasing the muscle.
Re the previous comment on a muscle being damaged by trauma which causes arterial bleeding out of the muscle; then whilst this is not a particularly 'good thing', it does lessen the chance of crush syndrome, as the pressure within the muscle will be released. At this stage, whatever the situation is re the 'victim', it is inevitably nothing less than very serious.
An issue with someone sustaining crush syndrome, is that at some point, the dead/damaged muscle tissue will inevitably be released back into the circulatory system. When this happens, many 'toxins' (for want of a better word) are suddenly released. Some of these can prove fatal in the short term, and others prove fatal in the longer term (3 days plus).
Realistically, for true crush syndrome, the victim will need fast access to surgical and medical treatment. Initially to remove the cause of the crush syndrome injury ( possibly a fasciotomy - internet search not for the feint hearted), with specialist medical care, usually involving a nephrology team, to manage the damage caused to the kidneys as a result of toxins released from the damaged muscle: this may require the need for short term treatment by haemodialysis.
Unlike pressure-sores/skin/soft tissue repair, muscles, once 'dead', tend to remain that way.

Please note that my observations are an attempt the clarify the term 'crush syndrome', and not to suspension trauma in general. A person may sustain horrific / life threatening injuries by being crushed (back to the dodgy boulder choke again), but it does not necessarily mean they have crush syndrome. Confusing and quite possibly a little bit pedantic, and for which no apology is given in this particular instance.