Near miss in Imlay

[spinesnaper]

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

Tom

I am telling you that I was having a problem. As it turned out the fireman's belay was at least psychologically helpful. I was in fact tied off at that point and was not going anywhere but I was trying to figure out why I was having the issue and what to do to comfortably and safely finish my rap. I did not really sort it out hanging there. I simply recovered enough that I could safely complete the remaining 20 feet of the rap. As you can see, others have experienced this type of suspension trauma. I think I was lucky here. I am certainly happy this did not occur on the last rap.

Ken

[Bootboy]

I'm not a chiropractor, and I never said anything about a WFR course.

You're right that it was likely an issue of blood flow, which I stated, but the instance I cited is also possible. Do a little homework and you'll learn that. You may be right that it wasn't a nerve of the lumbar plexus, but there are myriad nerves in the region of your back where your harness would make contact, the higher your harness rides, the greater the likelihood of this happening, though still less than a vascular issue.

[spinesnaper]

I'm not a chiropractor, and I never said anything about a WFR course.

You're right that it was likely an issue of blood flow, which I stated, but the instance I cited is also possible. Do a little homework and you'll learn that. You may be right that it wasn't a nerve of the lumbar plexus, but there are myriad nerves in the region of your back where your harness would make contact, the higher your harness rides, the greater the likelihood of this happening, though still less than a vascular issue.

Wait, are you sure you're not a chiropractor?

I have done my homework. Trust me, I have done my homework. I didn't just stay at a Holiday Inn. I am actually an associate clinical professor at the David Geffen School of Medicine at UCLA. On this one I know what I am talking about. However, if you have an actual reference that supports your position, please share it with me so I can understand where you are coming from.

Ken

[ratagonia]

Picked the wrong guy to arm wrestle with, Bootboy.

Ken - I recently tried a harness (that sucked) and had kind of the same problem, though less so especially since it was only for the subway. The rise was way too high, so the waistbelt was too high and effected my ability to breath. Thankfully, the raps in the Subway are short enough you don't really have to.

I'm not saying your harness was this bad, but perhaps it was getting there, and applied too much pressure on the diaphram. a poorly fitting harness also can distribute the weight poorly. Sometimes just the extra slop from the harness getting wet plus wetsuit can make the harness fit poorly enough to produce some undesirable effects.

As part of the diagnosis, did you mention how the harness/you felt on the final rappel?

Tom

[jman]

Wait, are you sure you're not a chiropractor?

I have done my homework. Trust me, I have done my homework. I didn't just stay at a Holiday Inn. I am actually an associate clinical professor at the David Geffen School of Medicine at UCLA. On this one I know what I am talking about. However, if you have an actual reference that supports your position, please share it with me so I can understand where you are coming from.

Ken

Our resident Doctor! :)

We did the free rappel in Pleiades once with my mother who is 64 and had a similar experience to what you had, she said.

She claims her backpack was high on her back and she rappels at like a 120degree angle and the weight from the backpack was pulling her down while she was trying to keep stay upright made her breathing difficult.

Sure it's not exactly the same but I have to ask perhaps the angle of how you were sitting in the rappel made a difference? I dunno, but that's what my mum said about her "scary rappel" when she couldn't breathe.

[Brian in SLC]

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.

"Many"? My guess is not. There's gobs of survivors of rappelling accidents and I dimly recall not hearing any of them say they felt faint or like they were passing out as the cause of their loss of control.

Orthostatic hypotension...interesting deal. Scary. Every blue moon I stand quickly out of a chair and feel faint...

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658225/

Dehydration a player more than likely, harness fit, maybe some other malady that might cause low blood pressure. Worth havin' your partners keep an eye on you.

You're not taking any diuretics or vasodilators? Are you anemic?

Scary business. Yeah, I'd be making sure my harness fit well and I'd hang my pack from it when rappelling.

[spinesnaper]

"Many"? My guess is not. There's gobs of survivors of rappelling accidents and I dimly recall not hearing any of them say they felt faint or like they were passing out as the cause of their loss of control.

Orthostatic hypotension...interesting deal. Scary. Every blue moon I stand quickly out of a chair and feel faint...

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658225/

Dehydration a player more than likely, harness fit, maybe some other malady that might cause low blood pressure. Worth havin' your partners keep an eye on you.

You're not taking any diuretics or vasodilators? Are you anemic?

Scary business. Yeah, I'd be making sure my harness fit well and I'd hang my pack from it when rappelling.

No, this was suspension trauma i.e. interference with venous return due to harness compression. No diuretics or vasodilators. And no I am not anemic. Did great on the last rap due to hanging my pack and using a figure of 8 to take some of the chest weight.

And yes you did provide a reference on suspension trauma from 2007. There are of course many more papers on this subject that unfortunately does not seem to be part of the canyoneering curriculum and should be.

Ken

[hank moon]

No, this was suspension trauma i.e. interference with venous return due to harness compression.

I am still wondering about your judgment in this case. From what I can see with web-o-vision, you seem willing to gloss over other potential factors that probably played a significant role, such as dehydration, exhaustion, etc. And perhaps you are also predisposed to faint for some reason(s)?* Note that suspension trauma can be induced entirely through hanging motionless in a harness, without any additional contributing factors, such as you had. However, this takes considerable time - and motionlessness - which were not factors in your case.

I am as interested as you are (maybe...) in learning more about suspension trauma and sincerely thank you for sharing your frightening experience in Imlay. However, I do think you have rushed to judgment in this instance. So, I challenge you to remove your helmet and don the science hat. On your next trip to the PC pit toilet, you might while away the minutes with some fine imported HHS / ST literature:

http://www.hse.gov.uk/research/rrpdf/rr708.pdf


*I certainly am - once literally fell off the table while having blood drawn

hank

p.s. can/would you share links to some of the videos you mentioned earlier?

[spinesnaper]

Hank

That is actually a very good reference you posted.

Here study this video posted on Youtube. I think that many of use have already seen this but think about this accident in light of this discussion on suspension trauma:



I was looking for other video but the ones I have found could be consistent with a "slip." Of course if you are on the verge of passing out, almost any video will look like a slip.

It is also worth emphasizing that our knowledge of suspension trauma is by no means complete. I do agree that dehydration would of course be a predisposing factor but then perhaps this is always the case.

Ken

[Bootboy]

I can't find a source but it was explained to me by an ER doctor friend of mine. I asked him about last night at work. I've likely interpolated some incorrect information. Forgive meHe explained to me that trauma, even relatively mild, to the muscles of the lumbar region, can result in vertigo. He mentioned something about propriocetors and their relationship to the cerebellum leading to this. He said its more common in car accidents and in conjunction with whiplash injuries but can also occur with compression of the muscles and nerves of the lumbar region. He thought that rappelling with a pack on, if your weight is shifted back so that you had enough pressure on that region from your harness, could be more than enough to cause the sensation of vertigo, even a near syncopal episode.

[Brian in SLC]

Here study this video posted on Youtube. I think that many of use have already seen this but think about this accident in light of this discussion on suspension trauma:

Discussed here.

http://www.bogley.com/forum/showthre...appel-Accident

Doesn't make me think of suspension trauma in the least...

[spinesnaper]

And there is the testimony of the participant:

"He and his buddy were getting ready for a 300-foot rappel in the park this past Tuesday. Schriever went first while his buddy videotaped him. Right away, though, both knew something was wrong.

"I lose control and stop midway because there was a knot in the rope. So that saved me from falling even further," Schriever explained while watching the video.

But once he untied the knot, he couldn't stop. Schriever fell more than 100 feet, banging hard against the rock wall before dropping to the rocks below.

"I remember the first hit on my head, and it wasn't until I watched the video that I realized I hit at least two more times on the way down," he said.

[COLOR=#000000]In that split second, all Schriever could think of was his wife, two daughters and his unborn son, who is due in just two weeks. "I was like,

[ratagonia]

But then it begs the question of why did he lose control in the first place?

The fact that this does not make you think of suspension trauma, does not mean that it plays no role in this accidents.

You're really stretching for it Ken.

The guy was an idiot, had NO idea what he was doing, and set his rappel device with practically no friction. It is a real stretch to look further than that.

Sure, he could have had a stroke, been abducted by aliens for one second and returned with paralysis of his brake hand, or hit a gravitational anomaly caused by a passing Black Hole - all these seem as likely to the idea that he had instantaneous compartment syndrome causing loss of blood pressure to his brain.

Jus' sayin'...

Tom

[hank moon]

Ken, it seems to me that this incident could lead to some interesting safety research. While I disagree with your assertion that it was "suspension trauma" (a phenomenon associated with prolonged, motionless suspension in a harness) per se, I think we can both agree that it bears further study and increased awareness in the vertical community.

What happened to you* (and perhaps several others) seems to have been related more to top-heaviness than to the harness. Do you have access to any test facilities in your area where this issue might be studied further? Any interest in that?

hank

* 6 rap abs? Recline of doom? La-Z-Boy rap?

p.s. My worst experience in this vein was rappelling down Tilted Well (165') in Run to the Mill Cave, TN. I was supporting a cave diving expedition and had an old-school steel SCUBA tank on my back. Hellish. Good thing I was young and still relatively fresh, energy-wise.

[joeb]

What was your breathing rate on the rap? Maybe a combination of dehydration, fatigue & hyperventilation caused the issue? During my time lifeguarding at the ocean the last thirty years we see a lot of rescues where fatigue, panic plus rapid breathing causes the victim to feel like they are going to "black-out" and some of course do. I am not saying you were panicky but you were definitely in a state of physical & mental fatigue (face it - you were going down Imlay for the first time) and my guess is that the imbalanced pack got you scared and the adrenaline/rapid breathing kicked into overdrive. Whether or not hyperventilation/etc caused the issue, who knows but it could be a possibility versus a harness restriction issue

[spinesnaper]

What was your breathing rate on the rap? Maybe a combination of dehydration, fatigue & hyperventilation caused the issue? During my time lifeguarding at the ocean the last thirty years we see a lot of rescues where fatigue, panic plus rapid breathing causes the victim to feel like they are going to "black-out" and some of course do. I am not saying you were panicky but you were definitely in a state of physical & mental fatigue (face it - you were going down Imlay for the first time) and my guess is that the imbalanced pack got you scared and the adrenaline/rapid breathing kicked into overdrive. Whether or not hyperventilation/etc caused the issue, who knows but it could be a possibility versus a harness restriction issue

Tom

I know they teach skepticism at MIT so you are doing your job.

Having now reread and reviewed what rappel accidents reports I can from such great sources as bogley and youtube, I agree that most do seem to be associated with the participant releasing their hand from the brake side of the rope thereby profoundly increasing the effects of gravity on the rappel system. The anomaly of why the hand is released in many cases seems to be a slip causing the rappellers body to be slammed against a rock wall were upon the hand releases and I think we are all aware of what happens next. So far so good.

On the other hand, I know what I experienced and felt the harness compression which I do think was related to being top heavy and I have already acknowledged that dehydration certainly could play a role. Generally I am not anxious rappelling and did not have a concern until into the free hanging portion of this rappel when I experienced compression from my harness, top heaviness and lightheadedness all at the same time. I did consider just zipping down the rope but I was concerned that I might not be in control so fought the sensation, locked off my ATS and called for a fireman's belay. That worked out for me.

I think one makes a serious mistake assuming that suspension trauma only occurs hanging motionless for an extended period of time although this is the classical description. As for access for facilities to further research this issue, I am weight training an advanced team of top heavy rats as we speak to model the effects-just kidding. No I don't have resources for this and considering people have actually died suspended in harness suspension rescue scenarios, I suspect that an institutional human subjects protection committee would likely be reluctant to actually approve such research without a lot of very expensive life/safety safeguards in place. I am actually surprised that there is not more information from military research on this subject.

However, if I experience this again, I certainly will up date this thread accordingly.

Ken

[Brian in SLC]

But then it begs the question of why did he lose control in the first place?

The fact that this does not make you think of suspension trauma, does not mean that it plays no role in this accidents.Ken

"Schriever admits he didn't use the right gear and rope and he didn't wrap his safety line enough times around his rope. He's hoping this video will show others who love to rappel that no matter how experienced you are, you should always be 100 percent careful -- you usually don't get two chances."

You used it as a possible example to support your position. I still don't see any indication that the cause was in any way related to anything other than inexperience. He never mentioned he felt faint. Ect.

I follow accidents in both climbing and canyoning fairly closely. I own around 20 years of ANAM data. You could look up ACC (Alpine Club of Canada) data too as they keep fairly extensive records on accidents. Its just not on my radar.

I challenge you to find a single accident in the canyoning world that has even a remote mention of suspension trauma as a potential cause. There's plenty of rappelling accidents every year. And, they get picked apart for cause by us Monday morning quarterbacks.

Have had a few friends who've lost control on rappels...never due to feeling faint as a cause. Mostly lack of proper management of friction.

Stay hydrated. Get a harness that fits. Remember to breath when on rappel. Get the weight off your back especially on long drops with free air. All good stuff.

[joeb]

"I suspect that an institutional human subjects protection committee would likely be reluctant to actually approve such research without a lot of very expensive life/safety safeguards in place" - This is why when I was doing my Master's research we used lawyers instead of rats. No public outcry and here in California there is no shortage of them.

[hank moon]

Stay hydrated. Get a harness that fits. Remember to breath when on rappel. Get the weight off your back especially on long drops with free air. All good stuff.

X2

and...doctors should be skeptical, too :)

[spinesnaper]

"I suspect that an institutional human subjects protection committee would likely be reluctant to actually approve such research without a lot of very expensive life/safety safeguards in place" - This is why when I was doing my Master's research we used lawyers instead of rats. No public outcry and here in California there is no shortage of them.

Sweet

I am skeptical. Just sharing an experience. Ignore it at your own peril.

By the way, here are some recent references:

http://www.wemjournal.org/article/S1...320-0/fulltext

Hum Factors. 2012 Jun;54(3):346-57.

Impact of harness fit on suspension tolerance.

Hsiao H, Turner N, Whisler R, Zwiener J.
Source

Protective Technology Branch, Division of Safety Research, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., Morgantown, WV 26505, USA. hxh4@cdc.gov

Abstract

OBJECTIVE:

This study investigated the effect of body size and shape and harness fit on suspension tolerance time.
BACKGROUND:

Fall victims may develop suspension trauma, a potentially fatal reduction of return blood flow from legs to the heart and brain, after a successfully arrested fall if they are not rescued quickly or the harness does not fit them well.
METHOD:

For this study, 20 men and 17 women with construction experience were suspended from the dorsal D-ring of a full-body fall-arrest harness. Their suspension tolerance time, physical characteristics, and harness fit levels were assessed.
RESULTS:

Body characteristics (i.e., weight, stature, upper- and lower-torso depths) were associated with decreased suspension tolerance time (r = -.36 - -.45, p < or = .03). In addition, harness fit affected suspension tolerance time; workers with a torso angle of suspension greater than 35 degrees, a thigh strap angle greater than 50 degrees, or a poorly fitting harness size had shorter suspension tolerance time (mean differences = 14, 11, and 9.8 min, respectively, p < or = .05).
CONCLUSION:

Body size and harness fit were predictors of suspension tolerance time. Selecting well-fit harnesses and establishing a 9-min rescue plan are suggested to ensure that no more than 5% of workers would experience suspension trauma.
APPLICATIONS:

The study provides a basis for harness designers, standards writers, and manufacturers to improve harness configurations and testing requirements for better worker protection against suspension trauma.