Suspension Trauma

[mikem]

Also literature search done a couple of years ago (USA. Linkedin was Australian):

Fatal and non-fatal injuries due to suspension trauma syndrome: A systematic review of definition, pathophysiology, and management controversies

Suspension trauma syndrome is a life-threatening event that occurs when a person is “trapped” in a prolonged passive suspension. It is most commonly seen in people who engage in occupational or sport activities that require harness suspension. ...

www.ncbi.nlm.nih.gov

 

[georgenorth]

It’s interesting that there seems to be so much focus on what to do with the casualty once they’ve been rescued. For me the primary focus should be on the ability to rescue someone from the rope promptly should they become incapacitated for any reason.

Unlike in the industrial world, rope rescue is rarely (if ever?) practiced by cavers. I wonder how many people I go caving with could rescue me off a croll if I was stuck between rebelays for instance.

 

[aricooperdavis]

Unlike in the industrial world, rope rescue is rarely (if ever?) practiced by cavers.

Sad if true, because it's really good fun! We ran "speed pluck-off" as a game at SCHECC a few years ago and it was wild - a great way to share knowledge.

 

[georgenorth]

Sad if true, because it's really good fun! We ran "speed pluck-off" as a game at SCHECC a few years ago and it was wild - a great way to share knowledge.

Definitely! We used to do rescue practice when I was learning SRT with DUSA. I think I’ve only done it once (prior to a YSS expedition) in the intervening 20 years! I suspect this is fairly typical.
Unfortunately it’s one of those skills that you do need to practice to have any chance of doing it competently given the added stress of an actual incident.

 

[Bob Mehew]

Also literature search done a couple of years ago (USA. Linkedin was Australian):

Fatal and non-fatal injuries due to suspension trauma syndrome: A systematic review of definition, pathophysiology, and management controversies

Suspension trauma syndrome is a life-threatening event that occurs when a person is “trapped” in a prolonged passive suspension. It is most commonly seen in people who engage in occupational or sport activities that require harness suspension. ...

www.ncbi.nlm.nih.gov

The latest published document reviewing the topic is by Rauch et al on 2024 entitled "Suspension syndrome: a scoping review and recommendations from the International Commission for Mountain Emergency Medicine". The recommendations are written for medics and other qualified persons and assumes continuing monitoring, rather than members of the party responding to the emergency. If you want detail then I recommend Paul Seddon's 2002 HSE document on the topic as a starting point. As the HSE web site seems to have lost the page, PM me for a copy if you would like to read it. (I have 100MB of downlaoded documents on the topic - a long read.)

Sad if true, because it's really good fun! We ran "speed pluck-off" as a game at SCHECC a few years ago and it was wild - a great way to share knowledge.

Idea for a Hidden Earth competition?

 

[JAshley73]

Unlike in the industrial world, rope rescue is rarely (if ever?) practiced by cavers. I wonder how many people I go caving with could rescue me off a croll if I was stuck between rebelays for instance.

The subject of vertical practice probably doesn't get enough attention. I mean, given the choice, would you (as a caver) rather "practice" SRT, or just go caving?

Oddly, I have more opportunity for small bits of time to practice, and fewer opportunities for larger blocks of time to go caving. So I built a practice rope rig in my garage. I was out there last night practicing changeovers & climbing with various bits of equipment. (And my daughter, rapelling on a bobbin...)

I have 14' from the floor to the anchor. Not much space, but enough to practice changeovers. Next will come passing knots, both up and down. I just received in the post a few bolt-hangers, the idea being to hang a few to practice deviations and rebelays eventually.

On the subject of pickoffs... I rescued a full-size punching bag from the trash a while ago for my young son to pound on. I'm thinking with a little personal-rigging ingenuity, it's about the right size & weight for a "small" unconscious caver to be picked-off. In time...

 

[Ane]

Definitely! We used to do rescue practice when I was learning SRT with DUSA. I think I’ve only done it once (prior to a YSS expedition) in the intervening 20 years! I suspect this is fairly typical.
Unfortunately it’s one of those skills that you do need to practice to have any chance of doing it competently given the added stress of an actual incident.

Since I’m feeling nostalgic, here’s actual photographic evidence of DUSA doing rescue practice some 16 or so years ago

 

[mikem]

Seddon's paper (from earlier in thread):

It's available on the archive.org copy of the HSE website here

 

[mikem]

ncbi link at top was also posted by someone else back on page 2 of this discussion.

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.

I can't find any details on the Danish incident, but being military it may have been a parachute harness, or back mounted attachment, both of which means you hang forwards when unconscious and compromise your breathing. Ascending kit holds you more upright than descending, but at least your head can loll back to keep your airway open (a narrow rift, or being against a wall, may prevent this).

 

[pwhole]

One big issue with doing a 'rope access'-style snatch rescue underground (and on many rope access jobs!) is the integrity of the anchors. Two people thrashing around on one pair of anchors (or perhaps even a single) would put an immense load on them, so they would have to be known to be capable of taking that load before attempting anything like this. Training centres often use massive steel beams to rig from, not common in caves - and pitches may only be rigged on temporary screws if in an exploration area - perhaps even Spits. It wouldn't be cool to lose two people instead of one.

Many rope access jobs are equally nasty when it comes to rescue potential, and some of the techniques taught would be literally impossible to implement in some of the real-world scenarios actually encountered.

 

[2xw]

One big issue with doing a 'rope access'-style snatch rescue underground (and on many rope access jobs!) is the integrity of the anchors. Two people thrashing around on one pair of anchors (or perhaps even a single) would put an immense load on them, so they would have to be known to be capable of taking that load before attempting anything like this. Training centres often use massive steel beams to rig from, not common in caves - and pitches may only be rigged on temporary screws if in an exploration area - perhaps even Spits. It wouldn't be cool to lose two people instead of one.

Many rope access jobs are equally nasty when it comes to rescue potential, and some of the techniques taught would be literally impossible to implement in some of the real-world scenarios actually encountered.

I have a suspicion that (and it's not really related to the thread I guess) we spend more time practising the cure than the prevention, because practising ropework is more fun than talking about group management or appropriate training etc. As far as I see it if you need to croll to croll someone then there have been many failures leading up to that (with few exceptions)

 

[georgenorth]

One big issue with doing a 'rope access'-style snatch rescue underground (and on many rope access jobs!) is the integrity of the anchors. Two people thrashing around on one pair of anchors (or perhaps even a single) would put an immense load on them, so they would have to be known to be capable of taking that load before attempting anything like this. Training centres often use massive steel beams to rig from, not common in caves - and pitches may only be rigged on temporary screws if in an exploration area - perhaps even Spits. It wouldn't be cool to lose two people instead of one.

Many rope access jobs are equally nasty when it comes to rescue potential, and some of the techniques taught would be literally impossible to implement in some of the real-world scenarios actually encountered.

Have you got any figures for what this ‘immense load’ actually is? It seems unlikely to be that high given the slipping load on the croll and stop is so low (3-5 kN from memory).

 

[Fjell]

We were practising a few days ago having already decided that the only practical method is to cut above the Croll, especially for my wife getting me. The pendulum is complicated, takes too long and could fail. Sods Law dictates it will be dark and wet. I very much believe in practising one method if possible and I can’t think of any scenarios where it doesn’t work. I would recommend doing it and actually cutting the rope if you haven’t before. Maybe don’t want to do this for the first time in a cave. Also remember to take a knife each, which is not something we have been good at.

This is not the point to worry about the rig, that was earlier when you installed it.

 

[Bob Mehew]

I can't find any details on the Danish incident, but being military it may have been a parachute harness, or back mounted attachment, both of which means you hang forwards when unconscious and compromise your breathing. Ascending kit holds you more upright than descending, but at least your head can loll back to keep your airway open (a narrow rift, or being against a wall, may prevent this).

I am moderately confident that the Danish incident is one reported by Madsen et al "Tolerance to Head-up Tilt and Suspension With Elevated Legs" Aviation, Space and Environmental Medicine, Vol. 69, No. 8, pp781-784. August 1998 and cited as Reference 2 by Seddon. I purchased a copy of the paper being curious and it states:

During first aid training, a 25-yr-old soldier was suspended from a wall with a strop around his thorax in order to simulate hanging. He was left unobserved for approximately 6 rain and was subsequently found lifeless and taken down. A physician arrived after an additional 6 min; he diagnosed the soldier with cardiac arrest and initiated cardiopulmonary resuscitation with success. On admission to the emergency unit the soldier was in sinus rhythm (that is normal heart rhythm). However, he soon developed ventricular fibrillation (that is a malfunction of the normal rhythm), and despite DC-conversion (that is a treatment aimed at correcting the rhythm), he never regained consciousness and died with signs of ischemic brain damage (an injury that results from impaired blood flow to the brain). The patient was without signs of strangulation (no bursted conjunctival capillaries (in the eyelids), no marks on the neck), and he did not suffer from any disease prior to the incident, nor was he taking any medication.

Items in italics are my additions.

 

[mikem]

Sounds horrendous. Thanks

 

[Bob Mehew]

Have you got any figures for what this ‘immense load’ actually is? It seems unlikely to be that high given the slipping load on the croll and stop is so low (3-5 kN from memory).

The BCA anchors are each good for way above 20kN. It is more likely the rope will break than an anchor fail. Lyon's work for the HSE indicated peak forces by a person moving abruptly might reach a factor of two of body mass, say 2kN. There would need to be a fall onto slack rope to get forces above that.

 

[mikem]

The modern anchors are, but the rock isn't necessarily, then there are spits / expansion bolts...

 

[georgenorth]

The BCA anchors are each good for way above 20kN. It is more likely the rope will break than an anchor fail. Lyon's work for the HSE indicated peak forces by a person moving abruptly might reach a factor of two of body mass, say 2kN. There would need to be a fall onto slack rope to get forces above that.

Thanks Bob,

So realistically the worst case scenario for load on the top anchor is going to be in the region of 4kN during a rescue.

Even 8mm thrubolts typically have an axial strength >10kN. I think if the anchor/bolts were so bad that I wouldn’t want to carry out a rescue on them, then I’d be pretty hesitant to use them in the first place!

 

[alanw]

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.

 

[alanw]

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.

Another report just in from East Cornwall Search & Rescue Team Facebook post