IWR or Pure oxygen

[Jean eve]

originally posted by DEEPLOU
Some information seems missing, like how long was he out of the water. YOu say he shouted for help, but did he have no symptoms of DCS?

The time he was out of the water was unknown since he already felt unconcious at the bottom.When he regain consious he shouted for help(don't know how long he was at the surface)but have sign of dizziness.But even if he don't have symptoms of DCS,I think he is not in a 'missed stop procedure' because he was already unconsious at the bottom.

 

[Rickg]

Jean eve,

Here are links to a lot of data that discusses IWR using both air and oxygen. There is a ton of data to sift through here.

I find IWR to be an interesting subject and thought you might find some of these links worth perusing. The first URL in particular has links to wealth of knowledge on this subject.

http://www.cisatlantic.com/trimix/AQUAcorps/Bent/inwater/IWR.htm

http://www.cisatlantic.com/trimix/AQUAcorps/Bent/inwater/IWRcasestud.htm

http://www.fullcave.com/REMOTEDIVING.htm

http://www.pathcom.com/~bracuk/RecScuba/Pages/InWaterRecompression.html

And here is what I found to be the best of the bunch. A true story written by someone who has experienced IWR. He wasn't able to complete the full oxygen IWR treatment course but you walk away with the idea that he feels even his partial IWR probably prevented him from having a worse case of DCS.

http://staff.washington.edu/parker/scuba/tech/bendstory2.htm

I've never had a DCS hit and hope I never do but some of this might come in handy if I ever should have a hit while in a remote location. For example, we will be going on a liveaboard out of Manado, Indonesia next month for a 6-day/5-night trip up to the Sangihe Islands which are pretty remote (probably in excess of 12 hours from a recompression chamber for a vast majority of the trip).

Hope this gives you something to think about. Best of all dive conservatively and you'll probably never need to consider this.

Rickg

 

[Mako Mark]

There is one diver on board quickly brought him down to half of the depth(11m)and start doing IWR with normal air.Lucky enough,he didn't have any sign of DCS.Sounds impossible but it is true!
.

This actually sounds more like a case of Omitted decompression not IW Recompression to me.

The diver did not have any symptoms and was only on the surface for a short time. The unconsuiousness is the complcating factor, but it is an interesting case. We could use more details.

 

[DEEPLOU]

The time he was out of the water was unknown since he already felt unconcious at the bottom.When he regain consious he shouted for help(don't know how long he was at the surface)but have sign of dizziness.But even if he don't have symptoms of DCS,I think he is not in a 'missed stop procedure' because he was already unconsious at the bottom.

It appeared to me that from the original description of the incident, that the unconsiousness was the result of lack of oxygen (air), not lack of decompression.
Upon regaining consciousness, the feeling of dizziness could also be result of oxygen deficiency.

Of course, this is all "Monday morning quarterbacking".

 

[Jean eve]

Originally posted by Cacun Mark
This actually sounds more like a case of Omitted decompression not IW Recompression to me.

Originally posted by deeplou
It appeared to me that from the original description of the incident, that the unconsiousness was the result of lack of oxygen (air), not lack of decompression.

well ,I think I get what you all mean and I also get all the IWR information I want.Thanks folks!
If it is Omitted decopression,why he was brought to half of the depth to start decompress or it is not necessary to do that?
So the unconsiousness was the result of lack of oxygen,can it led to DCS/DCI??

 

[sharpenu]

A missed deco stop from 22m (70 feet or so) for 50', while a violation of the rec tables, should not be enough to be a major DCS hit. Depending on the profile of the dive, this may not have even resulted in a DCS hit. I don't think it would be enough to be fatal in any case.

Heading to the surface from 70 feet with 50 bar (725 psi or so- if he had an AL 80, this should be enough for an 8 minute stop plus his ascent, even assuming a SAC of 1.0cfm), and he couldnt make a deco stop before he went OOA?

The advice you got here was good, though. Instead of concerning yourself with IWR procedures, try paying attention to your gas and BT. A diver that has an OOA as a "newbie" has NO BUSINESS attempting decompression diving. Havent we all seen enough of our fellow divers die? Especially from a stupid mistake like that.

 

[Jean eve]

Originally posted by sharpenu
A missed deco stop from 22m (70 feet or so) for 50', while a violation of the rec tables, should not be enough to be a major DCS hit. Depending on the profile of the dive, this may not have even resulted in a DCS hit. I don't think it would be enough to be fatal in any case.

Well,maybe for rec diving it is not a major hit.But we're working down there and the work is quite virgorous.We are all using a 'working decompressed table' and according to the table there is a 7min stop at 3m.

Heading to the surface from 70 feet with 50 bar (725 psi or so- if he had an AL 80, this should be enough for an 8 minute stop plus his ascent, even assuming a SAC of 1.0cfm), and he couldnt make a deco stop before he went OOA?

If there is still have 50 bar,of course it is enough for a stop.But unfortunately while still heading to the boat(have bottles attached at 4-5m)he was totally out of air!

A diver that has an OOA as a "newbie" has NO BUSINESS attempting decompression diving. Havent we all seen enough of our fellow divers die? Especially from a stupid mistake like that.

he was a 'newbie' is because he was a new diver in our farm.Every diver who worked in a pearl farm have to take a course for 6weeks(everydays) and have to passed the exam.After you passed this exam you got your level A license(Limit to 12m)After the License A,then go for another course(license B,limit till 60m)for 6weeks again and pass the exam.
The table we were using is a 'decompress table'.
When he was totally out of air and doesn't know what to do at that time,I think he was panic already.

Originally posted by Diver0001
Suffice it to say that this was an avoidable incident and your buddy doesn't need training in IWR, he needs training in gas management and watching his meters.

Usually there is enough air to go to the boat even it is 50bar.But after that we found out the SPG was faulty.The needle can't point to 0bar.
For the IWR training,it is not for my buddy but it is for me.
Better to learn one more thing than learn nothing.

 

[sharpenu]

What I mean by saying that 22m for 50 min not resulting in a hit, is that the Navy table calls for an NDL of 50 minutes at 70 feet (21 m) or an NDL of 40 minutes at 80 feet (24m). So the profile does give you a deco obligation, but I don't feel that any DCS hit you would wind up with would be serious enough to be fatal in itself.

As far as making it back to the boat, that is what I mean by needing more work on skills. I would rather spend my last 50 bar doing my required deco and then surface swimming to the boat, than missing my deco due to an OOA because I wanted to swim back to the boat underwater.

Also, the broken SPG is why it is important to check your gear every dive.

Poor planning and poor skills on the part of this diver.

 

[scuba_luv]

IWR works but it's hard to control and risky as compared to a chamber as the others have already said.

....AND.....

If you really need to apply IWR then you've already made some big mistakes and your procedures need work. In fact, I'd say that it's better to work on your procedures *before* you find yourself in this situation. For example (just to give you some ideas), you can think about gas management, surface support, staging Murphy bottles in the water (or along the ascent line), creating a deco tent with surface air supply, anchoring proper ascent lines for controlled deco levels, planning for deco situations instead of reacting to them, making use of experienced safety divers and so on....

Your interest in IWR is understandable but if I were you I would put my effort into avoiding the problem instead of reacting to it.

R..

It seems to me that I would like to be prepared and learn what to do if a fellow diver requires IWR. From what I've read it's critical to have tender divers and divers available to help with gear, ferrying down fresh tanks when needed, etc. I would like to know how to help in this sort of situation rather than stand by and just explain to everyone how the diver in trouble screwed up and why I'm OK. Save that for after the emergency is over and the situation is resolved.

 

[Jean eve]

Originally posted by sharpenu
What I mean by saying that 22m for 50 min not resulting in a hit, is that the Navy table calls for an NDL of 50 minutes at 70 feet (21 m) or an NDL of 40 minutes at 80 feet (24m). So the profile does give you a deco obligation, but I don't feel that any DCS hit you would wind up with would be serious enough to be fatal in itself.

Maybe for you it is not serious enough to be fatal,but if one day you have a chance to come to Tahiti and see how a pearl farm diver work(not all),then you will have nothing to say.We are not like a rec diver,swimming ,look at the fish,coral;take some picture......Before I worked as a pearl farm diver,I'd the same thinking with you.The NDL of Navy table is 50 min at 70feet.So,there is no need to do decompress at 3m.Then you are wrong.There 'is' already some pearl farm diver here have this kind of thinking like you,and ended with DCS/DCI.Even some have to go to a Deco Chamber.It happen to a diver who ommited his deco for a 5 min stop(not many but only 5!) and was rushed to a deco chamber.Maybe for another diver with that kind of dive profile,he won't have any DCS/DCI.
I also know pearl diver who sometimes ommited the deco but still good.There is also some diver used a lift bag to fast ascent to the surface from depth at 23m(playing with their life)but nothing happen to them.But we don't know what will happen if we don't follow our table.We don't scare of 10000 but scared of 1/10000.For 10000 times you do this,if you get it in one of the 10000 it is enough for you already.
That is why we have to always stick to our table not Navy table or other table....

As far as making it back to the boat, that is what I mean by needing more work on skills. I would rather spend my last 50 bar doing my required deco and then surface swimming to the boat, than missing my deco due to an OOA because I wanted to swim back to the boat underwater.

For me I also rather spend my last 50 bar doing my required deco like you said if I'm doing a leisure dive but we are working in a peal farm and there is rules.Every working company also have their own rules.
As I said,50 bar is enough to get to the boat to change the tank and continue to work.If you make the stop and then surface swiming to the boat,take another tank go down and continue to work again.Will you???This is the work of the day and the diver have to finish it.That is why he don't go to the surface to make a deco stop and go back because the work no yet done.There is a pearl farm I know,if an oyster fall down to the sea,the diver have to go and get it even if he is just finish the dive and the depth is 55m.Again,the 50 bar is enough to go to the boat,but the SPG stop funtioning when it is 50 bar.

For a faulty spg,how do you know it will become faulty in the middle of your dive???We can't know it will become faulty even if we check it before the dive.Maybe you will say have to check your gauge every 5min or .....during the dive.
I try to get in this diver situation.Even you check your gauge every min at that kind of situation,your mind is concerntrate trying to follow your buddy to get you to the boat.It is difficult to notice that the needle can't go down.
I read an article about a diver(my judgement from the article,he is quite experience.Maybe if you read the article you will said that he is not an experience diver),he had the same thing happen to him,a faulty SPG in the dive.When he notice it ,it is already out of air.Maybe there is also some experience or skillful diver check their SPG but I think not so frequently during the dive.But this is an accident!Even if you have a good skill,sometimes we do have some accidents.
Of course we always try our best to avoid it!