In-Water Recompression, Revisited

[The Chairman]

OK, I'll be blunt;

Speaking of being blunt... did you ever figure out why you were bent in the first place or is it still a mystery?

 

[Akimbo]

@Kay Dee

It wasn't long ago that just mentioning IWR would elicit nearly universal hysteria, but nobody would talk about what you're suppose to do if you get bent great distances from a barrel. I would hope the take-away from this thread is to be well prepared for DCS. It's not a hard decision when you are on an expedition dive with a group of pros. But how many people even ask about emergency treatment on the liveaboard they just booked? They all seam to know about the hot tub but how many check the distance to an operational chamber or an IWR kit?

 

[Duke Dive Medicine]

Sir, while l agree that a Table 5 performed in-water may be considered dangerous by some / many I do not accept per se that IWR of itself is dangerous when performed correctly.

Kay Dee,

Apologies, I didn't mean to imply that. If you read back through the thread you will find my/Duke Dive Medicine's position on in-water recompression, which is that it there are times when it may be considered when it is part of a safety plan and is undertaken by trained, experienced and properly equipped teams using established protocols. The in-water TT5 that was proposed in the article is NOT an established protocol and is extremely dangerous.

Best regards,
DDM

 

[Kay Dee]

Speaking of being blunt... did you ever figure out why you were bent in the first place or is it still a mystery?

Sure did! I made a mistake, so I am to blame and take resposibility for my own actions.

 

[Duke Dive Medicine]

Is IWR the dangerous practice or diving great distances from a chamber? Once you elect to dive hours or days away from treatment you have to make the conscious decision to choose the option that sucks the least. The sad part is too many divers don't think about it at all rather than making the conscious decision.
IMHO, IWR sucks less IF DCS is correctly diagnosed AND your are properly prepared. Emphasis on the "if" and "sucks less".

Sorry, I guess I could have made that more clear. The underwater TT5 is the dangerous practice.

Best regards,
DDM

 

[Akimbo]

Sure did! I made a mistake, so I am to blame and take resposibility for my own actions.

Fair enough... but DCS doesn't care if it is your screw-up or not. One of the very best diving supervisors I ever worked with was a Navy Master Diver. My life was literally in his hands many times and I never broke a sweat over it. However, he would get bend in the knee if he looked at a set of doubles sideways and would burn though them like a gas turbine. Old injuries, diver errors, unlucky genetics, or it's just your time doesn't matter much when you are laying on deck, can't control your bladder, and only have bad options to choose from.

 

[Kay Dee]

Fair enough... but DCS doesn't care if it is your screw-up or not. One of the very best diving supervisors I even worked with was a Navy Master Diver. My life was literally in his hands many times and I never broke a sweat over it. However, he would get bend in the knee if he looked at a set of doubles sideways and would burn though them like a gas turbine. Old injuries, diver errors, unlucky genetics, or it's just your time doesn't matter much when you are laying on deck, can't control your bladder, and only have bad options to choose from.

AGREED, and the some!

 

[Akimbo]

Sorry, I guess I could have made that more clear. The underwater TT5 is the dangerous practice...

I couldn't agree more... but I would probably do it with a well-trained crew and I had a CNS hit in the middle of the Pacific. It always comes down to the alternatives.

 

[victorzamora]

OK, I'll be blunt; i.e. with no other option, no chamber available within hours say, and the extremely fast and crippling onset of symptoms I myself experienced, I'd rather take what is deemd a 'bad IWR protocol' as opposed to the high possibility of being a cripple the rest of my life. But thats just me.

I couldn't agree more... but I would probably do it with a well-trained crew and I had a CNS hit in the middle of the Pacific. It always comes down to the alternatives.

To both of you: Why follow a "bad" IWR protocol when there are "safer" IWR protocols?

Kay Dee, you're talking about following a dangerous IWR protocol to prevent a crippling onset of symptoms. Why not follow a safer protocol?

If we, as cautious technical divers, are to prepare ourselves for an eventuality such as a DCS hit, shouldn't we prepare ourselves by familiarizing ourselves with the most up-to-date recommendations of medical professionals? Why settle for a schedule that wasn't meant for IWR? Why not a safer and more effective IWR procedure? I'm all for prepping for and knowing a good IWR procedure. I've been involved with two separate IWR incidents. Neither was in as bad of shape as you described, in that they both got back in the water under their own power. However, both were following pre-acknowledged IWR plans, supported by a small team at the surface and supervised by a team underwater with them (one supervisor in one case, two in the other). Multiple mixes, multiple bottles, plenty of spare gas, and a full non-rebreather setup for surface O2 were available. We have since added a FFM to our kit (long story) and will be practicing with it to make sure we're all comfortable with it in case we ever need it.

 

[Akimbo]

To both of you: Why follow a "bad" IWR protocol when there are "safer" IWR protocols?

"Bad" is not an appropriate choice of words. More aggressive and higher risk much more dangerous would be more accurate. @Duke Dive Medicine's original post dealt with using a standard US Navy Treatment Table 5 for IWR, which looks like this:
US Navy Diving Manual, Revision 7, Figure 17-4, Page 893

This protocol (TT5) is designed to be administered in a chamber with an inside attendant for Type 1 DCS. Note the two 20 minute treatment cycles at 60' on pure Oxygen, or a 2.82 ppO2. Typical IWR protocols call for treatments at +/-20' or a ppO2 of 1.6 where the risk of Oxygen Toxicity is much less. However, the treatment efficacy is also much less.

Here is the definition of Type 1 DCS (Page 859):

17-4.2 Symptoms of Type I Decompression Sickness. Type I decompression sickness includes joint pain (musculoskeletal or pain-only symptoms) and symptoms involving the skin (cutaneous symptoms), or swelling and pain in lymph nodes.​

Very often, DCS symptoms worsen in the first minutes after initial onset of symptoms (Page 861).

17-4.4 Symptoms of Type II Decompression Sickness. In the early stages, symptoms of Type II decompression sickness may not be obvious and the stricken diver may consider them inconsequential. The diver may feel fatigued or weak and attribute the condition to overexertion. Even as weakness becomes more severe the diver may not seek treatment until walking, hearing, or urinating becomes difficult. Initial denial of DCS is common. For this reason, symptoms must be recognized during the post-dive period and treated before they become too severe. Type II, or serious, symptoms are divided into three categories: neurological, inner ear (staggers), and cardiopulmonary (chokes). Type I symptoms may or may not be present at the same time.​

So, here is a dilemma. Do you want the much safer (when in the water) but less effective treatment when you suspect a CNS hit (Type 2 DCS) or the much more dangerous but more effective TT5? It is very different if you have simple joint pain (Type 1) and symptoms subside at 20' under a typical IWR protocol. Given that, I'd be at 20' and counting my blessings.

Going in the water at all with a CNS hit is really dicey, to the point that OxTox may be the least of the risk factors that could kill you. There are no good choices, but sometimes you have to make one. Without very complete IWR preparation you are pretty well left with writing goodbye letters... if you are lucky enough to be able to.