Near miss in Imlay

[spinesnaper]

OK perhaps that is a bit dramatic.

However, I did have an issue with the second to the last rap. It is about 40 feet and free hanging. About half way down, I felt like was going to black out. I was carrying my pack which contained the water soaked 200 foot 8.3mm rope. My harness is a Petzl Corax. But this is precisely the same harness I have previously used. I simply replaced it due to wear. Adding to top heaviness over the past couple of years I have been doing a lot of work on my shoulder muscles to help a shoulder impingement. My chest size has gone from 39 to 42 so I am more top heavy than I have been in the past.

I felt top heavy and was straining to stay upright which seemed to be causing the sensation of blacking out. Feeling that I was at risk of loosing control, I called out for a fireman's belay. This allowed me to pull it together and get down. I changed things up for the last rap. I took off my pack and clipped it to my cows tail. I took a double length runner and made a figure of 8 which I put my arms through and clipped to the rope above my rap device (ATS). I started off nervous and at first tried to stay up right-not comfortable. Then I leaned back and stabilized at about 45 degrees from horizontal and could relax into this taking all the pressure off the diaphragm. From there I lowered away, easy.

I would appreciate any insight on these issues. This experience has given me an entirely new insight on rappel accidents. I am now convinced that suspension trauma can occur just from rappelling and loss of consciousness from suspension trauma during a rap could account for some accidents where a canyoneer appears to loose control in the middle of a rappel and then falls to the ground uncontrolled.

[2065toyota]

I clip a single biner to my upper left shoulder strap and after a big free starts starts will clip that biner to the the rope above the device. Then you just kick back and relax. It also adds one more small friction point

[ratagonia]

Suggestions:

Turn sideways. Honestly, your body is stronger when turned 90 degrees, rather than "flat".

For a canyon with a maximum rap length of 120 feet, don't bring a 200 foot rope.

Put your rope in a ropebag with flotation, then you can just chuck it down the drop into the pool. Make sure it has enough flotation for the rope you have in it.

Tom

[spinesnaper]

Suggestions:

For a canyon with a maximum rap length of 120 feet, don't bring a 200 foot rope.

Tom

Hmm, I think some of us have larger rope remudas than others. I did have the 200 in the dry bag. I can't tell you precisely why I decided to carry it out of the dry bag-thin oxygen in the parking lot perhaps.

While the body is stronger 90 degrees ( I assume you mean sitting up right) what I am saying is that I was having a problem sitting upright. I am looking to see if anyone has any experience with what I am talking about. I have not previously experienced an issue like this. Since rappel is perhaps the highest risk activity in canyoneering, I think it is worth talking about these types of problems.

Ken

[hank moon]

[QUOTE=spinesnaper] While the body is stronger 90 degrees ( I assume you mean sitting up right) what I am saying is that I was having a problem sitting upright. I am looking to see if anyone has any experience with what I am talking about. I have not previously experienced an issue like this. Since rappel is perhaps the highest risk activity in canyoneering, I think it is worth talking about these types of problems.


Half way down I felt I was getting suspension shock and at risk of passing out. I yelled for a fireman

[spinesnaper]

Briefly,

Suspension trauma only occurs when one is already unconscious / immobile, so I don't think it is relevant here. Judging from your post in another thread (2nd paragraph of quote, above), I think your faintness was probably related to nutrition (hydration, electrolyte + blood sugar levels. Did you grab a good bite to eat with some water + electrolytes before completing the last rappel?

I think Tom was saying that if you turned a bit sideways to the wall (instead of facing it), the greater lateral rigidity of the skeleton would have helped alleviate the muscle strain (hope that makes sense - I'm not a doctor). I recently had a struggle staying upright on a rap and stopped mid-rap to transfer the pack from my back to hanging from the rap device 'biner. Saved my aching abs and made the remainder of the rap a lot more pleasant.

Glad you weren't going down first, Ken! Great TR and congratulations on completing Imlay.

Hank

Thanks for your kind comments.

Just for reference, I am a surgeon. Suspension trauma is actually poorly understood. What we do know is that the harness affects the circulation from the legs causing a lack of blood flow to the brain producing a black out or lack of consciousness. The suspension causes the black out. In almost every other circumstance, a passed out human being would not stay up right. In the suspension situation, this does not mechanically occur and it is thought that this has some bearing on eventual death presumably by cerebral ischemia.

This is the first time I have ever experienced anything like this. I don't think it was related to my state of hydration or nutrition. Think back to all those videos we have seen where the rappeller is making smooth progress down and then suddenly seems to slip out of control and fall from the rappel.

I am suggesting that suspension trauma is the cause of many of these accidents. If we could reliably determine the root causes of these types of accidents, we could advise individuals as to what steps to always take to avoid these types of situations. It might be to remove upper torso weight ( i.e. hang your pack), have a chest loop to distribute the upper torso weight, etc.

I am curious to see if others have experienced this feeling as well.

Ken

[ratagonia]

I think Tom was saying that if you turned a bit sideways to the wall (instead of facing it), the greater lateral rigidity of the skeleton would have helped alleviate the muscle strain (hope that makes sense - I'm not a doctor).

Yeah. I lack a good set of words to describe what I am trying to say. Only a surgeon would know the technical terms...

Actually, maybe a surgical comparison would do. A Normal surgical position would be face up or face down. What I am saying is, your body is stronger, your ABS are stronger, when your body is facing face-sideways, rather than in the classic sitting position. I have found rotating my hips so one hip is down relieves the strain on my rather weak abs.

On that rap, my great thanks to Hank for calling up to me to hang... your... pack... when he realized this was a good idea. Communication was difficult with a lot of wind, so I greatly appreciate the thought, time and effort required to make that communication.

Tom

[ratagonia]

Hank

Thanks for your kind comments.

Just for reference, I am a surgeon. Suspension trauma is actually poorly understood. What we do know is that the harness affects the circulation from the legs causing a lack of blood flow to the brain producing a black out or lack of consciousness. The suspension causes the black out. In almost every other circumstance, a passed out human being would not stay up right. In the suspension situation, this does not mechanically occur and it is thought that this has some bearing on eventual death presumably by cerebral ischemia.

This is the first time I have ever experienced anything like this. I don't think it was related to my state of hydration or nutrition. Think back to all those videos we have seen where the rappeller is making smooth progress down and then suddenly seems to slip out of control and fall from the rappel.

I am suggesting that suspension trauma is the cause of many of these accidents. If we could reliably determine the root causes of these types of accidents, we could advise individuals as to what steps to always take to avoid these types of situations. It might be to remove upper torso weight ( i.e. hang your pack), have a chest loop to distribute the upper torso weight, etc.

I am curious to see if others have experienced this feeling as well.

Ken

How about this theory?????:

Late in the day, low on food, blood pressure down quite a bit. Clenching your abs for quite some time results in a further decrease in blood pressure ==> faintness.

Yeah, there is probably a fair amount of blood sequestered down in the legs at the same time, since those muscles are still. I would think suspension trauma partly comes about because the leg muscles (and arterial/venous/capillary muscles) relax and therefore the blood volume in the legs increases, and MORE blood ends up sequestered in the legs, since return flow is blocked. Seems like this would not happen in a few minutes.

Tom

[spinesnaper]

Tom

I am putting it out there and asking questions. You have studied more accident reports than most of us. Dehydration a contributing factor is certainly plausible. Just don't ask me to go back in there and give myself an IV bolus of fluids before starting down next time (but I am sure it would make me have felt a lot better). It is worth noting that suspension trauma can induce unconsciousness and remaining up right is thought to contribute to death. Interesting subject and I wonder if it contributes to more rappelling accidents than we realize.

Ken

[Aj84737]

I'm not a doctor. But I stayed at a holiday inn express last night.

[spinesnaper]

I'm not a doctor. But I stayed at a holiday inn express last night.

Oh, this big needle. Trust me... this isn't going to hurt a bit.

[nonot]

Sounds like your body was working overtime. I've almost passed out while swimming 100 yards at the end of a canyon, floating on my back. Sometimes, if your nutrition worked out that day how it did and you were working hard during the day, at the end, the body sometimes wants to shut down at an inconvenient time. I could see the ab workout at the end of a long day in Imlay triggering this. It may not be related to the harness at all.

[spinesnaper]

No this seemed mechanical related to the harness and being squeezed. Harness fit does seem to be a factor in suspension trauma and as Tom points out, one can't dismiss what happens when the tank is not full.

[2065toyota]

Gotta remember to breath also which is hard to do under stress sometimes

[ilipichicuma]

A similar thing happened to me when I was rappelling the big waterfall at Stewart Falls. It was a pretty long rap and I had a soaked 200 foot rope in my backpack. I had a hard time staying upright and started to feel faint. However, as I have since done several longer raps, I attribute this to the heaviness of the backpack. I really don't think my harness had anything to do with it. If I had had the sense to hang my pack there I'm sure I would have been fine.

[Iceaxe]

FWIW- I have a rather large friend I do canyons with occasionally. He often clips a quick draw to the haul loop on his backpack and to the rope near his head. This creates what he calls a lazyboy chair as he rests while leaning back against his pack on long free hanging rappals.

Tap'n on my Galaxy G3

[oldno7]

Spine
Is your harness compressing any arteries? Shoulder strap on pack? Did something fit different than before? New pressure point?
I was always of the belief that suspension trauma took more time than what is usually encountered on a rappel.
Sounds like lack of blood flow to me. And I did take first aid once(to qualify my opinion)

[Bootboy]

Your harness around the small of your back won't necessarily occlude any major arteries. The dizzy-near-passing-out sensation likely comes from the compression of a nerve of the lumbar plexus. Not that you should try it, but if you lean back in a chair that hits you right about the level of your shoulder blades, after a minute or two you'll get the sensation of falling over backwards and blacking out. It's kind if scary. The same thing can realistically happen anywhere along the length of your spine , and your harness can certainly exert enough pressure in the sweet spot.

It could also be a matter of blood flow but that would be caused by the leg loops on your harness. They would restrict return flow from your legs which, if it happens quickly doesn't allow your body time to compensate. Thus a rapid drop in blood pressure could cause you to black out.

[spinesnaper]

Your harness around the small of your back won't necessarily occlude any major arteries. The dizzy-near-passing-out sensation likely comes from the compression of a nerve of the lumbar plexus. Not that you should try it, but if you lean back in a chair that hits you right about the level of your shoulder blades, after a minute or two you'll get the sensation of falling over backwards and blacking out. It's kind if scary. The same thing can realistically happen anywhere along the length of your spine , and your harness can certainly exert enough pressure in the sweet spot.

It could also be a matter of blood flow but that would be caused by the leg loops on your harness. They would restrict return flow from your legs which, if it happens quickly doesn't allow your body time to compensate. Thus a rapid drop in blood pressure could cause you to black out.

Ouch. OK Bootboy. I seriously hope you are not a chiropractor because I am about to hurt your feelings. The dizzy-near passing out sensation is not caused from "compression of a nerve of the lumbar plexus." I know they did not teach you that at your wilderness first responder course. Perhaps you have the lumbar plexus confused with the solar plexus. Pinched nerves cause shooting pain down the legs and can also be responsible for various types of sensory and motor nerve dysfunction. Perhaps some type of extreme ridiculopathy might cause one to faint but typically these syndromes are associated with shooting pain down the back of the legs, numbness, and various degrees of leg weakness. The precise distribution of these signs allows one to localize the level of the disc pathology. That has nothing to do with what I experienced.

I was blacking out because my harness was interfering with venous return to the heart. Tom is correct that dehydration might contribute to this state. Harness fit also has something to do with it. What I was experiencing represents some type of suspension trauma. Classically this is thought to occur after more than 9 minutes of harness suspension were the legs are immobile. Compression of the legs and torso interferes with venous return from the lower extremities. This impairs blood flow to the brain and can cause loss of consciousness. Prolonged suspension is associated with systemic shock and death.

The more of this literature I read the more clear that this is really a poorly understood entity. I was hoping by making this post to elicit information from SAR types who may have more direct knowledge of this entity. I am just thankful that my partner was available to give me a fireman's belay so I could get reorganized. Like it or not, I am telling you that this is probably the cause of more than a few rappelling accidents where the rappeller seems to just let go of their brake hands and fall uncontrolled down the rope. There are more than a few videos out there showing this.

And yes you are right that rapid drops in blood pressure do cause people to faint.

Ken

[ratagonia]

I am just thankful that my partner was available to give me a fireman's belay so I could get reorganized.

Perhaps it is a bit too obvious, but...

Could not you have stopped, tied off, got both hands free and got your excrement together without a fireman's belay? Kind of a basic rap skill to stop and tie off, yes?

Tom