Localised DCS

[DrSteve]

Hi!

I have read on this board of several incidences where people received a DCS hit that was localised due to e.g. wrapping the hang line around their arm, tight boots which cut off circulation. I mentioned this during a class as an interesting tid bit and also to have students remember not to wrap themselves up and also to get comfortable/snug gear as opposed to tight. The instructor "challeneged" me afterwards to come up with some references to support my stories which are by definition anecdotal. Does anyone know of any references or stats which address this occurance?

Thanks in advance,

Steve

 

[Kendall Raine]

Hi!

I have read on this board of several incidences where people received a DCS hit that was localised due to e.g. wrapping the hang line around their arm, tight boots which cut off circulation. I mentioned this during a class as an interesting tid bit and also to have students remember not to wrap themselves up and also to get comfortable/snug gear as opposed to tight. The instructor "challeneged" me afterwards to come up with some references to support my stories which are by definition anecdotal. Does anyone know of any references or stats which address this occurance?

Thanks in advance,

Steve

The problem is differentiating between causation and correlation in the stories. Restricted blood flow is not a good idea in diving for all sorts of reasons including perfusion. If your instructor challenges that concept find another instructor who knows something about decompression theory.

Wrapping oneself in the hang line is also countraindicated.

 

[DrSteve]

The problem is differentiating between causation and correlation in the stories. Restricted blood flow is not a good idea in diving for all sorts of reasons including perfusion. If your instructor challenges that concept find another instructor who knows something about decompression theory.

Wrapping oneself in the hang line is also countraindicated.

LOL I did emphasise it was a circulation issue and the restriction thereof. I think she just wants some proof so she feels comfortable putting the concept out to a class. She's *very* anal like that

 

[rjack321]

What would constitute "proof"?? How about having her dive with a tourniquet and seeing what happens :mooner:

I don't know of any published statistics on where hits have occurred in the body and what may have been constricting circulation (which is inherently a major wild card).

Really this is basic physiology here.

 

[Kendall Raine]

LOL I did emphasise it was a circulation issue and the restriction thereof. I think she just wants some proof so she feels comfortable putting the concept out to a class. She's *very* anal like that

Proof. Hmm. OK. I'll play.

I have a friend who came back from a benign profile off the rigs in California complaining of pain in her wrist. The pain was proximate to where she was wearing a digital BT. She thought there might be a connection. She went for an extended chamber ride (TT6 with four extensions). Experienced gradual improvement during treatment. Suffered the usual horrid burning in the chest after 10 hours on HBO and wrist was still slightly sore for a few days afterward.

Was she bent? If so, was it related to constriction from the BT?

Another friend had an inflator malfunction on a deep trimix dive and had to hold the inflator with his left hand during deco-don't ask me why he didn't just shut that side down or disconnect it, I wasn't there. He wasn't able to flex his elbow during the hour long hang and took a pretty obvious pain hit in that elbow. Unlike the woman, it's pretty clear he was bent. It resolved on initial chamber recompression. Was it due to the contracted position of his elbow? Would he have taken the hit in that elbow anyway?

See where I'm going with this? Proof is elusive.

Gene Hobbs at Rubicon might know if any research has been done on tight fitting garments and DCS, but I suspect whatever research he finds-he'll find it if it exists-will be inferential/tangential at best. The problem is how is a researcher going to get a grant to test human subjects for this? You just can't ask volunteers to strap themselves in duct tape and then get bent. Animal trials would be tough, too, since how is the mouse going to tell his wrist hurts?

Good luck.

 

[Gene_Hobbs]

Gene Hobbs at Rubicon might know if any research has been done on tight fitting garments and DCS, but I suspect whatever research he finds-he'll find it if it exists-will be inferential/tangential at best. The problem is how is a researcher going to get a grant to test human subjects for this? You just can't ask volunteers to strap themselves in duct tape and then get bent. Animal trials would be tough, too, since how is the mouse going to tell his wrist hurts?

Thanks for the vote of confidence but... <g>

I look at this when the thread was first posted. There are 517 hits for the term "localized DCS" in the Rubicon Research Repository. I did not have a chance to refine the search but it could be worth the time. There have been a few case reports over the years and we see patients that could attribute these symptoms to hanging in flow after deeper dives off the NC coast a few times a year. I know some of the old US Navy reports show cases that would be of interest but I am not familiar enough with that data to be much help.

Research could be done with DAN's Project Dive Exploration but here again it would take years to get any significant evidence. The other problem is diver denial. It is not hard to dismiss a DCS symptom and a musculoskeletal injury when you know you have been straining so under reporting is not probably not uncommon.

Altitude DCS case reports are also interesting for exercise and DCS, non-ambulatory vs. ambulatory, repetitive motion injuries, etc...

Sorry...

 

[Saturation]

Gene Hobbs at Rubicon might know if any research has been done on tight fitting garments and DCS, but I suspect whatever research he finds-he'll find it if it exists-will be inferential/tangential at best. The problem is how is a researcher going to get a grant to test human subjects for this? You just can't ask volunteers to strap themselves in duct tape and then get bent. Animal trials would be tough, too, since how is the mouse going to tell his wrist hurts?

Good luck.

Generally I do not think there is a specific study looking at bends supposedly induced by a physical restriction or a manouver, although it is well known motion is a risk factor for increasing bends risk.

Frequently, various studies are done using torniquets to reduce blood flow to a limb to reduce drug effects there. Its done in today's version of ECT as treatment for severe depression, to suggest reducing blood flow can be induced quite easily.

I personally have gotten what I think is localized skin bends from tight fitting gear, its not bends per se because its only a small segment of high inert gas tension from an entire body's worth of inert gas. I used to wear my gauges much tighter as wrist mounts, and noticed a purple rash on my skin around the strap. It fades in minutes. The straps are not tight enough to impair circulation to my hand, so the whole hand is not 'purple' either, but its just on the superficial surfaces of skin. In contrast, I notice nothing wearing the gauges as tight on the surface or on most recreational dives.

 

[DrSteve]

What great answers thank you everyone! I have tried to get onto the Rubicon Repository, but for some reason could never get the web to connect. I'll do some further research. Let's face it, if OJ can be cleared of murder but be guilty of "wrongful death" then this information should be enough to prove that restriction could contribute to a localised bend.

 

[Dr Deco]

Hello DrSteve:

I also do not know of any studies with restriction. It makes sense that reducing blood flow during decompression is a move towards DCS.


PS I am in the midst of a move and have had very limited access to my computer. Please bear with me…



Dr Deco :doctor: