Suspension Trauma

[Speleofish]

Completely agree with ian.p. There are a few situations where tourniquets are useful but, in the field, the only time I'd use one would be to control catastrophic bleeding. There may be some sense in putting the rescued person in a semi-recumbent position and gradually lying them flat (over 30 minutes or so) but only if they are fully conscious and defending their airway. In most situations, putting them in the recovery position will be the least worst option.

 

[i think it goes]

The instructor was very good and had quite a lot of experience so I won't slate them - as I mentioned this wasn't part of the actual course and was more of a question I had. Perhaps they answered more in the vein of a general serious crush injury than suspension trauma and I misinterpreted. Regardless, constructive criticism is very useful and this thread has come up with lots of good links and places to follow up and I'll be sure to do so. Thanks everyone for the feedback!

 

[Bob Mehew]

The instructor went on to say that suspension trauma was treated as a crush injury and about how relieving the pressure on the legs may result in CO2 rich blood rushing back into the core, causing further issues. They suggested that the appropriate course of action was to apply a tourniquet further up the legs (in this case) to replicate the crush injury and then move the casualty to a safe position as quickly as possible - the thinking being that once a tourniquet is applied it should not be removed. This makes sense to me but I also see the idea in other suggestions in the thread. Will have to do more research.

Groan. Hopefully your research will reveal the error in this advice. Please ensure you cover what precisely are the consequences of a crush injury and of a suspension trauma. And then identify what are the impacts of letting the blood recirculate in both cases. I will give you a hint, you should find there are far more consequences and impacts for a crush injury than for suspension trauma. I would be grateful for a PM if the result of your research is too long for a contribution.

 

[Brendan]

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

 

[hannahb]

Thanks Brendan.

Sounds like we were misplaced in our thinking in our student group. We never considered that becoming unconscious would be the problem but focussed on the build up of toxins.

Really interesting discussion.

I'm curious about the reports in one of the links of a few people being "ok" on the rope and then dying very quickly during or after rescue, once released. Does that sound like something different?

 

[i think it goes]

I attended a wilderness first aid course over the weekend and had a great time and learned a lot. Admittedly, the course was not covering suspension trauma so this advice should be taken with a pinch of salt but the topic was brought up. The instructor mentioned a case regarding the army and a drill to do a mid-rope rescue where the pretend casualty actually ended up with suspension trauma after roughly 6 mins due to being fully inverted for this time. Was surprised how fast it could come on!

The instructor went on to say that suspension trauma was treated as a crush injury and about how relieving the pressure on the legs may result in CO2 rich blood rushing back into the core, causing further issues. They suggested that the appropriate course of action was to apply a tourniquet further up the legs (in this case) to replicate the crush injury and then move the casualty to a safe position as quickly as possible - the thinking being that once a tourniquet is applied it should not be removed. This makes sense to me but I also see the idea in other suggestions in the thread. Will have to do more research.

EDIT: After chatting to others on my course, I realise I have incorrectly added the section about CO2 rich blood, this is my mistake and not what the instructor said. Their view was instead that the increase in volume of blood returning back to the core may cause further issues.

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

My medical advice would be to avoid both of these conditions

Some sound advice

 

[FabianE]

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

Hi Brendan,

Thanks for your medical input into this topic... something which has interested me for some time.

It's interesting to see that some American based associations until recently supported the 'W'-position based on the rationale that this position forces blood to be returned to the heart at a slower rate due to the added gravity. Even the fowler position was recommended for a certain timeframe before altering the position into a more seated or horizontal position.

Whereas the UK and Australian sources focus on airway management by placing the casualty directly into the recovery position.
Makes sense... ABC!

I think there is an interesting topic to look at the evidence and most recent research / data to see what the best thing to do is...
I've not found anything relating to tourniquet use in suspension trauma, it also feels wrong to me as we use tourniquets mainly for catastrophic haemorrhage...

Fabian

 

[ian.p]

I'm curious about the reports in one of the links of a few people being "ok" on the rope and then dying very quickly during or after rescue, once released. Does that sound like something different?

Casualties going into cardiac arrest at point of rescue is a well recognized phenomenon that has been observed in a number of settings and may be due to a number of factors of which hypothermia is often a significant contributory factor. As a rule handle anyone who has been very cold, in water or dangling for a prolonged period of time as gently as possible. Keeping your casualty warm is always a good idea.

 

[Jim MacPherson]

I've had a hypothermic event once and as a casualty I can happily (now) confirm it's utterly disorientating and deeply scary, I had no real idea what was happening beyond my vision suddenly got very blurry, apparently I was mumbling (even more) gibberish. I kept on trying to pull off the blanket I was given because I felt too warm.

Bearing in mind this was in a hospital following an operation, in bed and during the morning doctors' round I could hardly have been in a better place and the staff were relatively used to how I reacted.

The more relevant information and training you can get the better, dealing with trauma in a cave/ mine or virtually anywhere will be nearly as scary for first responders, the more confident in providing appropriate care probably the better for both the casualty and the people providing help.

I did have to encourage a crag fast walker over the bad step on Sharp Edge, bit safer than going down the ridge and help reverse a terrified first-time caver down Hobson's Choice, those circumstances were not easy for any of us and that was with giving physical help and verbal support.

Jim

 

[Fjell]

When recovering someone from cold water (ie hypothermic most likely) it has always been said to keep them horizontal until they warm up, including when lifting them out of the water. This is very difficult to impossible on a short handed boat as your only realistic option is to lift them straight up using the lifejacket (sit) harness on a halyard. I assume this is still valid advice from what I read above? You are also going to be effectively suspended in the water on leg loops.

 

[mikem]

Most people will float to some extent, so won't have their full weight on a lifejacket, that they would have on a sit harness. the problem there is usually them being cold & not very effective at pumping blood around.

 

[Brendan]

When recovering someone from cold water (ie hypothermic most likely) it has always been said to keep them horizontal until they warm up, including when lifting them out of the water. This is very difficult to impossible on a short handed boat as your only realistic option is to lift them straight up using the lifejacket (sit) harness on a halyard. I assume this is still valid advice from what I read above? You are also going to be effectively suspended in the water on leg loops.

One of the major issues with rescuing people from prolonged immersion in water is that you float vertically (i.e. head up, legs down in the water). Water, being dense, exerts significant external pressure on the body, compressing the blood vessels and helping maintain blood pressure by pushing blood centrally. In addition, hypothermia results in increased uring output, so the circulation becomes volume depleted. Once removed from the water, that external pressure is lost, and if kept vertical, the blood pressure can collapse as blood pools in the lower body, compounded by the volume depletion. This has been associated with deaths of people winched vertically from the sea. For that reason, the advice is to try and keep victims horizontal to negate the pressure change. Clearly you may need to lift someone over the side of a boat, but the vertical time should be as limited as possible, and they should be positioned horizontally as soon as possible

Article explaining this in much more detail here https://www.researchgate.net/profil...sociated-with-rescue-of-immersion-victims.pdf

 

[Cantclimbtom]

One of the major issues with rescuing people ... ... ... has been associated with deaths of people winched vertically from the sea... ... ...

I was winched from water once (training) years ago and it was the single strap under armpits, I was surprised how physical it was and it took a bit of effort (naively I'd assumed as long as my arms were down it'd be very relaxing fun). Anyone in that state with only the armpit strap would probably be winched up, faint and end up dropped in the water again. I note these days that it's common to have a second strap just below the bum to keep someone in a more recumbent state

 

[Tangent_tracker]

It has happened and there are accounts of it. Because it's relatively sudden in onset and brain death can occur alarmingly quickly, it's (IIRC) the reason why the CIC assessment(s) for mid rope rescue give you a 6 minute window to effectively and capably execute the rescue, be it traverse, ascent to descent, or descent to descent, past a deviation or rebelay (and if you can't do it in this time, you fail or get deferred for re-assessment ); sudden onset can result in death but I think the main reason for the time constraint(s) is to ensure an airway can be maintained in the event of unconsciousness on rope. In reality my guess/hunch is that most mid-rope emergencies wouldn't get solved in anything even remotely sub-six-minutes so the casualty would have to rely on good fortune/luck etc.. Mid rope rescue isn't something to entertain lightly as it can easily result in additional collateral. By the time cave rescue have turned up I would imagine it's a case of que sera, sera. I also recall it has other names/terms such as Harness Induced Pathology, Orthostatic Intolerance etc., but admittedly it has been a while since I re-upped on this topic. Despite its rarity it should be food for thought for all cavers doing SRT because my feeling is that many cavers believe that being able to progress on rope up/down/sideways equates to being an SRT caver whereas the full gamut of techniques including rigging/derigging/improvised and full rescue would be my preferred definition for being "able to do SRT".

I have to attend tower rescue courses for my work, (none-IRATA) and the prioritty taught is to get a concious casualty to raise their legs using their pole belt or similar. I think this is easily overlooked and could extend rescue times with cavers by a significant amount.
I have noticed when acending big pitches (70m+) my legs swell up slightly in my petzl harness, noticed by putting my fingers under the leg loops. Never felt unwell or showed symptoms, but if I am tired and need rest I will generally raise them in my footloops...

 

[alanw]

The Winter 2024 edition of Mountain Rescue Magazine has an article on Suspension Trauma (p21)

 

[JAshley73]

American here...

Let me first thank @Brendan for his excellent post on Suspension Trauma, Crush Injuries, and the confusion, and separation of those two conditions.

I was introduced to SRT just a few months ago, and suspension trauma was discussed very early in the training. We didn't spend much time on it, but it was discussed how serious the condition is. One of our instructors who was pretty competent in SRT (had been doing rope-work with his father, since his childhood, long before his introduction to caving,) anecdotally mentioned how he had a scare with this, as a volunteer during rescue training. He mentioned how after just a few minutes, he felt "really bad" and had to abandon the training exercise.

With that at the forefront, it's been top of mind as I keep learning and practicing skills.

Despite its rarity it should be food for thought for all cavers doing SRT because my feeling is that many cavers believe that being able to progress on rope up/down/sideways equates to being an SRT caver whereas the full gamut of techniques including rigging/derigging/improvised and full rescue would be my preferred definition for being "able to do SRT".

This line of thinking has certainly inspired a set of goals for myself, in regards to SRT skills. The idea of having to "save" someone in our caving party, is inspiration for me to learn at minimum, how to perform a pick-off for a stuck caver on-rope. (And then how to treat them...)

 

[JAshley73]

From the USA's NSS, SPAR manual on suspension trauma. (Small Party Assisted Rescue)

"The French asked volunteers in a lab-setting to pretend to be unconscious while on rope. They had people actually become unconscious within minutes. The Danish military had a volunteer pretend to be unconscious on rope so they could practice rescuing. That person was dead in six minutes. If a person is stuck on rope, it is imperative to get them down quickly.**
.........
For blood to return to the heart, it has to pass through a set of one-way valves in the legs. This requires muscle contractions to squeeze the blood uphill. When someone is not moving, the blood isn't circulated and the functional volume [of blood] decreases. This is a type of shock.

What compounds the problem is the body's response to shock is to faint, to be come unconscious. When you are upright and fall down, this improves blood flow to the brain. When you can't go to ground [because you are captured by the rope and your SRT equipment] the pulse drop and blood pressure drop when fainting catastrophically reduces blood-flow to the brain, seemingly to the point of death.
.............
Once off rope, threat the person like any other casualty. Lay them down, address their injuries, and feed & hydrate them if safe. There is an older way of thinking that recommended not to lay them down. This is incorrect. Get blood flow reestablished to the brain as soon as possible by getting them flat.***



** No citations or references were supplied along with the text. I just want to point that out. But, I must give benefit of the doubt to the instructors/authors who wrote the manual, until I'm privy to know otherwise...

***This manual was published in 2019. I'm not sure if the advice to lay the patient down horizontally is still best practice or not. After reading @Brendan 's thorough post above, it seems like the advise to lay the patient horizontally ASAP is correct and best.

 

[Tangent_tracker]

It has happened and there are accounts of it. Because it's relatively sudden in onset and brain death can occur alarmingly quickly, it's (IIRC) the reason why the CIC assessment(s) for mid rope rescue give you a 6 minute window to effectively and capably execute the rescue, be it traverse, ascent to descent, or descent to descent, past a deviation or rebelay (and if you can't do it in this time, you fail or get deferred for re-assessment ); sudden onset can result in death but I think the main reason for the time constraint(s) is to ensure an airway can be maintained in the event of unconsciousness on rope. In reality my guess/hunch is that most mid-rope emergencies wouldn't get solved in anything even remotely sub-six-minutes so the casualty would have to rely on good fortune/luck etc.. Mid rope rescue isn't something to entertain lightly as it can easily result in additional collateral. By the time cave rescue have turned up I would imagine it's a case of que sera, sera. I also recall it has other names/terms such as Harness Induced Pathology, Orthostatic Intolerance etc., but admittedly it has been a while since I re-upped on this topic. Despite its rarity it should be food for thought for all cavers doing SRT because my feeling is that many cavers believe that being able to progress on rope up/down/sideways equates to being an SRT caver whereas the full gamut of techniques including rigging/derigging/improvised and full rescue would be my preferred definition for being "able to do SRT".

If I ever whitnessed someone struggling and suspected ST I would imediately get them to raise their legs, which I think could potentially buy some time, potentially the difference between life and death.

It worries me that too many cavers dismiss things like this with "it hasn't happened in 40 years I've been caving" (normalsy bias/self delusion) or just plain "it will never happen" (denial). Anything can happen, and that is why it's best to think of all these scenarios and what could be done if it were to happen.
Suspension trauma will not just be a case of sitting in a harness too long (although it can be), but will most likely be a combination of things that all add up to a it being a greater chance than the sum of all contributary issues. Panic when things going wrong leading to fatigue, general tiredness, lack of fitness, unknown health issues, cold. Could all potentially add up to result in a bad day on a rope.

 

[Bob Mehew]

After reading @Brendan 's thorough post above, it seems like the advise to lay the patient horizontally ASAP is correct and best.

For the avoidance of doubt, Brendan's article states: "Once down, the casualty should be positioned horizontal, and managed in line with standard practice, ie an ABCDE approach". The BCA item on the topic see https://british-caving.org.uk/suspension-trauma/ states "laid in the recovery (safe airway) position". Other advice seen during the research for the BCA item suggested laying the casualty flat on their back. The concern which lead to the BCA advice was over the risk of choking if an unconscious patient is lying on their back. Plus the difference in height of the brain of a casualty between laid on their back and in the rescue position is minimal, under a couple of mm of mercury. Obviously dealing with life threatening wounds (cf major head injury with bleeding) would take priority over immediately placing the casualty in the recovery position.

 

[mikem]

Standard practice is to put someone in the recovery position if you aren't doing something else to treat them that requires them being on their back.

This is relevant:

Following Suspension Trauma, does the horizontal position increase rescue death in tower climbers?

One of the main benefits of the new wireless age is the ability to consolidate information from many sources, including those with similar operations but from different “occupations”. It also allows us with a few key strokes and associated phone calls to get a good feel for current policies in the w

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