In Water Recompression for DCI

[ScubaDadMiami]

One of the things not mentioned by the intial post is what happens when the evac arrives. Bolting back to the surface to get lifted out may cause even more serious problems. Remember, you mentioned that you are not on pure O2 but on 50 percent oxygen. While that boosts partial pressure, you are already bent and you are still breathing a mix that has nitrogen in it.

When you do a chamber ride, they bring you up to the surface very, very slowly. You can't expect the evac to sit there while you spend that kind of time surfacing.

In the end, if you are going to have to wait several hours, then go for it if you have to. On the other hand, it is better to stay on O2 while waiting for evac that is relatively close by. Exactly where to draw the line will be up to the individual. Everything has its risks and benefits.

 

[padiscubapro]

One of the things not mentioned by the intial post is what happens when the evac arrives. Bolting back to the surface to get lifted out may cause even more serious problems. Remember, you mentioned that you are not on pure O2 but on 50 percent oxygen. While that boosts partial pressure, you are already bent and you are still breathing a mix that has nitrogen in it.

When you do a chamber ride, they bring you up to the surface very, very slowly. You can't expect the evac to sit there while you spend that kind of time surfacing.

In the end, if you are going to have to wait several hours, then go for it if you have to. On the other hand, it is better to stay on O2 while waiting for evac that is relatively close by. Exactly where to draw the line will be up to the individual. Everything has its risks and benefits.

another consideration that has to be taken into fact is how much deco was blown and whatt gas was being breathed..

A Trimix diver who blew of a large deco is at a much higher risk than the same diver on a nitrogen mix..

If there is going to be a long wait for evac, and there was a large deco obligation blown off chances are the diver is in very deep S*** and waiting for an evac may be the difference between life or death.. It has to be a personal decison and the proper equipment and support is a must.. That being said if it happened to me and I had a competent buddy that I trust I would PERSONALLY attempt it on myself even if I didn't have a FFM as long a there was a big deco blown..

 

[jbd]

another consideration that has to be taken into fact is how much deco was blown and whatt gas was being breathed..

A Trimix diver who blew of a large deco is at a much higher risk than the same diver on a nitrogen mix..

If there is going to be a long wait for evac, and there was a large deco obligation blown off chances are the diver is in very deep S*** and waiting for an evac may be the difference between life or death.. It has to be a personal decison and the proper equipment and support is a must.. That being said if it happened to me and I had a competent buddy that I trust I would PERSONALLY attempt it on myself even if I didn't have a FFM as long a there was a big deco blown..

I understand what you are saying and agree, but will bring up a wrinkle in the program for most all divers.

If you decided to do IWR for whatever reason, how would you know what to do :06:

What depth, for how long, how do you know there is enough gas available, what stops would need to be made on the way up?

 

[MB]

...a wrinkle in the program... how would you know what to do... What depth, for how long... what stops would need to be made on the way up?

Gosh James, are you tryimg to spoil the fun of guesswork?

 

[pdoege]

What depth, for how long, how do you know there is enough gas available, what stops would need to be made on the way up?

TT6, baby!

http://wwwsam.brooks.af.mil/hyper/files/TT_USAF.PDF

Peter

 

[pipedope]

One of the things not mentioned by the intial post is what happens when the evac arrives. Bolting back to the surface to get lifted out may cause even more serious problems. Remember, you mentioned that you are not on pure O2 but on 50 percent oxygen. While that boosts partial pressure, you are already bent and you are still breathing a mix that has nitrogen in it.

When you do a chamber ride, they bring you up to the surface very, very slowly. You can't expect the evac to sit there while you spend that kind of time surfacing.

In the end, if you are going to have to wait several hours, then go for it if you have to. On the other hand, it is better to stay on O2 while waiting for evac that is relatively close by. Exactly where to draw the line will be up to the individual. Everything has its risks and benefits.

The key thing is that the places where most people would choose to do IWR have NO evac! The choice might be between IWR and getting to a chamber in DAYS or weeks.

My personal preferance is to have a chamber on site for diving having staged deco. In many cases this is not possible for rec divers especially if it requires a long charter of a bigger boat to have space for the chamber and support equipment.

IWR is a useful choice when the alternative is many days of travel to get to a chamber.

 

[BigJetDriver]

Hi, all!

In regard to the useful application of IWR, the two most important keys are: (1) patient assessment, and (2) risk/benefit analysis.

(1) The main question is: How badly is the patient affected? What is the result of the preliminary diver neuro exam? What is the current physical state of the diver? What was the extent of the exposure, i.e. gases used, time/dosage, etc? What is the prognosis?

(2) Are we prepared for IWR? Are the environmental conditions acceptable? Is there better help, i.e. chamber and medical staff within reasonable transport time and distance? Please note the word "reasonable" here. The farther you are away from shore-based or platform-based recompression and medical help, the more reasonable IWR becomes IF, and it is a large IF, (no pun intended) you are prepared for it!

In general, unless you have the set-up, the training, and the staff to assist, IWR is more dangerous to the patient/diver than surface 02 and transport.

It is, however, as Fins pointed out, a personal decision.

BJD :doctor:

(FYI: Just as a foot-note, I am a certified Diver Medic Technician and the course included study of the practice of IWR.)

Folks,

Pipedope has again pointed out the key to the whole thing. IF you are going a long way out, you MUST make some proper preparations, including provision for a chamber ($$$$) or IWR.

 

[jbd]

TT6, baby!

http://wwwsam.brooks.af.mil/hyper/files/TT_USAF.PDF

Peter

Peter,

Thats for chamber deco. MB picked up on my point. Even with the existence of TT 5 and TT 6 if a diver doesn't know about them at the time they need the info then its not useful.

 

[MB]

Thats for chamber deco... Even with the existence of TT 5 and TT 6 if a diver doesn't know about them at the time they need the info then its not useful.

Also, IWR requires additional attention to thermal protection & drowning prevenmtion. Not saying that IWR is never valuable, but knowing before starting could be helpful...

 

[FIXXERVI6]

What about sitting at 20 feet on pure 02 waiting for them to show up?