anyone want the truth and science on inwater recompression? It's incredibly effective

[boulderjohn]

60' on O2 would scare the crap out of me. Especially if your OTU's are high from a long dive already. I have never had or been involved in an incident where most or all of the deco was blown off. I have had and been around people who have had some sholder pain etc. after a dive. I can tell you from my experience that going back in the water and going to a depth where the pain subsides and then slowly reascending doing stops at every 10' for a few minutes at a time then staying at 10-20' on 02 for an extended time definitely makes you feel better. I am of the opinion that the sooner you can get recompressed the better. I think TDI is teaching an in water recompression class now. What depth are they recommending O2?

I am not aware of a course by TDI, but UTD has one. That developed somewhat out of necessity, since they had several divers need to use it on several occasions at a remote location.

This article by Pyle and Youngblood includes a history of the different protocols, most of which limit the depth to 30 feet using oxygen. I have not seen any protocols anywhere at any time advocating 60 feet. Some of them suggest a PPO2 ranging from 1.4 to 1.6, which is even more restrictive of depth.

It seems to me that if you think you are going to use this procedure in your future, you should study the various protocols, select one, and have both the necessary knowledge and equipment on hand when you dive.

 

[PfcAJ]

No one is "tracking"anything.I related incidents I have witnessed .I also related this is not something new or isolated. Nor is there a single incident of someone drowning or losing consciousness. Make of it what you will, but predictions of death and doom haven't been borne out in practice. I remember hearing the same clamor in the 80s when we would put 02 in a tank without telling the shop as nitrox wasn't common knowledge.

Sounds like you've got a solid sample size and a very scientific approach to the issue....

 

[boulderjohn]

Sounds like you've got a solid sample size and a very scientific approach to the issue....

For those who are interested in a more scholarly and scientific look at the issue, I suggest you check out the link I placed in post #61. One of the authors has been through the process twice, BTW.

 

[100days-a-year]

Best I could do,compile data about actual events as opposed to parroting what anyone can read on the net.

Like I said I have never had to do it as I follow my protocol rigidly and have been lucky as well.Based on what I have personally experienced I would feel comfortable @ 60 on 02 if I was hurt and treatment was a day minimum away.

 

[boulderjohn]

Best I could do,compile data about actual events as opposed to parroting what anyone can read on the net.

Like I said I have never had to do it as I follow my protocol rigidly and have been lucky as well.Based on what I have personally experienced I would feel comfortable @ 60 on 02 if I was hurt and treatment was a day minimum away.

It is possible for people to run across a busy interstate highway at night. In fact, I learned well after the fact that my son and a friend did that after their car broke down. The fact that they did it and lived does not make it a generally safe practice for everyone.

Again, read the Pyle and Youngblood article. It looks at specific documented historical incidents and makes solid scientific conclusions.

 

[PfcAJ]

Best I could do,compile data about actual events as opposed to parroting what anyone can read on the net.

Like I said I have never had to do it as I follow my protocol rigidly and have been lucky as well.Based on what I have personally experienced I would feel comfortable @ 60 on 02 if I was hurt and treatment was a day minimum away.

I think you're confusing 'data' with 'anecdote'.

A few events is not data, sry. What you're suggesting is unequivocally recognized as unsafe by scientists, decompression researchers, dive agencies, and nearly all divers (your subgroup being the only exception that I'm aware of). Even the few agencies that DO teach an IRW protocol place a max in water o2 depth at 30ft.

And what someone 'feels comfortable with' has no bearing at ALL on what constitutes sound practice.

 

[Kevrumbo]

Reference and FYI with caveats:

. . .We removed the Exceptional Exposure Oxygen tables from the NOAA diving manual 4th editon because there was fear that if the general public saw them printed that they might take it as an endorsement to use them.

The NOAA exceptional exposure limits are set for extreme emergencies only and are not for routine use. i.e. --should be used for life saving only.

These are for a working dive meaning with lite exertion. Remember that there are a variety of factors that come into oxygen toxicity, and crossing the 1.6 atm 45min line does not guarantee convulsion, it also does not guarantee it won't.

NOAA OXYGEN
EXCEPTIONAL EXPOSURE LIMITS
PO2 Minutes

2.8 5
2.4 10
2.0 30
1.9 45
1.8 60
1.7 75
1.6 120
1.5 150
1.4 160
1.3 240

As you can see the exceptional times allow you a fairly large margin to use this method for an "escape." The table is NOT linear. Note that exceptional exposures are DANGEROUS and can only be done once in a day. . .

Joel Silverstein

 

[kensuf]

That is true. It is also true that for reasons not understood, people can tolerate much greater pressures on O2 in a chamber than under water.

If you are going to use IWR, use one of the established IWR protocols, and have the appropriate equipment.

It's been awhile since I've followed up on the research, but there was a lot of speculation that it had to do with the mammalian diving reflex.

Regardless, speaking as someone that has toxed in a dry chamber while receiving a schedule 6, let me assure you it can still happen while you're dry, and it's not a fun way to spend an afternoon.

 

[Kevrumbo]

Have had partial paralysis clear up on guys who pushed the limits.Many times seen pain disappear on descent,generally a sign it was truly DCS.

We are rarely closer than 12 hours from the dock and trying to make a buck.We carry enough 02 to do IWR as it has worked many times on many people.Waiting to treat symptoms when you have gas available is sheer lunacy.

SOP is 60' on 02 for 10 to 20 minutes then 5 min at 50,40,30,20 and 10.2nd diver is either standing by or in the water with bent diver.

DO NOT TRY AT HOME OR WITHOUT TRAINING!

The better more gradual procedure -if you really need to go this deep to 60'/18m for relief of acute DCS symptoms- is Pyle's IWR profile (i.e. you don't necessarily descend straight to 18m breathing on O2):

In-water recompression - Wikipedia, the free encyclopedia

___
For simple type I DCS limb pain, the best & easiest IWR profile to apply is UTD's schedule, which is a modification on the old Australian Protocol:

9m depth on O2 for 30 min, 60 min or 90 min total Oxygen time;

10min breathing O2 with 5 min Air Break (Air Break time does not count -only O2 breathing time applies for 30min, 60min or 90min times at 9m);

Then slow 1 meter-per-10 min ascent to the surface with same 10min O2:5min Air Break (hold ascent while on 5 min Air Break) --should take well over two hours to surface from 9 meters.

Ideally you should have full AL80's of Oxygen & Air; use a full face mask reg, or at least a mouth mask reg for O2 breathing; a bosun's chair line rigging or deco hang bar for the patient at depth 9m; and an attendant Diver to watch & aid Patient for signs/symptoms of O2 Toxicity.

 

[100days-a-year]

We carry T bottles and have an AL80 full waiting normally with a reg on.As our exposure runs from 5-7 dives per day @ 100' to 5-7 @ 180' X 5-7 days and using profiles that are basically square and on Cochran or Orca computers DCS is always a possibility.

What we do is the result of 10s of thousands of dives over many years by a few dozen guys.I am a new guy with over 5000 dives and full tri-mix cert almost 15 years ago,4000 of which are commercial spearfishing.Some guys have 30-40+ years at that rate.One guy has a boat that has been fishing since 1974.We have learned .

Facemasks don't work in current,nor rigging other than a heavily weighted downline.

Get in at the first sign of DCS and not just soreness from work

As our BTs are short,there is no need for long hangs to completely unbend

30' doesn't work very often

Hop in on 02 soon if you blow deco for any reason(14' tiger etc..)

Even a guy flopping on the deck or partially paralyzed can be unbent,given they can keep a reg in their mouth while someone swims them down(where symptoms will sometimes immediately start improving)

1 of our anecdotes is worth 15 people online parroting what they read or opine in regards to spearfishing,diving,deco,seamanship,boat handling,fish populations etc....

I do appreciate the concern that lies behind the advice and references.