Accidents

[letoktok]

I recently watched a tv show where Navy divers after a long dive would theoretically have to do a 2 to 3 hour stop at fourty feet, but they don't the water is too cold and what not, instead they surface with no stops and in less than five minutes get unsuited and go in a chamber to decompress at 40f. Which is normal practice for that kind of diver.
My question is, why do most diving manuals suggest that if a mistake was done, take the diver to the clossest chamber and put him on o2. Why not if the mistake was identified early (Emergency Ascent) just grab a new bottle and reg and go back down to i don't know 36f or 40f if not only 30, stay there for 10 to 15mn (considering the dive wasn't supposed to be a decompression dive) and then ascend and just monitor the diver, even then bring him to a chamber. At least the bigger bubles would have, due to the pressure, gotten smaller and with the prolongued stay would have had time to exite the blood stream or the tissue.
Or am i completly missing something? i honestly don't understand. I do know that a lot of what if's would have to come into play, and maybe that's why they don't say you can do it... it would have to be under 5mn, a no deco dive etc...
If anybody can help?

 

[erubic]

I don't know the answer to you question, but I think it has something to do with introducing more nitrogen into your body. Have you done a search on this topic?

 

[scubasean]

I recently watched a tv show where Navy divers after a long dive would theoretically have to do a 2 to 3 hour stop at fourty feet, but they don't the water is too cold and what not, instead they surface with no stops and in less than five minutes get unsuited and go in a chamber to decompress at 40f. Which is normal practice for that kind of diver.
My question is, why do most diving manuals suggest that if a mistake was done, take the diver to the clossest chamber and put him on o2. Why not if the mistake was identified early (Emergency Ascent) just grab a new bottle and reg and go back down to i don't know 36f or 40f if not only 30, stay there for 10 to 15mn (considering the dive wasn't supposed to be a decompression dive) and then ascend and just monitor the diver, even then bring him to a chamber. At least the bigger bubles would have, due to the pressure, gotten smaller and with the prolongued stay would have had time to exite the blood stream or the tissue.
Or am i completly missing something? i honestly don't understand. I do know that a lot of what if's would have to come into play, and maybe that's why they don't say you can do it... it would have to be under 5mn, a no deco dive etc...
If anybody can help?

Managing a diver underwater who is at risk for DCS is probably very difficult, especially since you are putting that diver right back into the hostile environment (we don't breathe water...heh) again. If something happens while they are back in the water, having them in the water at the time might increase the problem rather than help it go away.

If that diver goes into convulsions, gets DCS, and can't manage on their own, passes out, etc., its probably really hard to get him back out of the water safely....

I've never had to remove an unconcious person from the water and would not like to start now.

But, you also say that, in your example, the dive "wasn't supposed to be a decompression dive..." which is not the same scenario that you presented with the navy diver above.

My guess is that greater minds will answer this better than I can....

 

[Saturation]

I recently watched a tv show where Navy divers after a long dive would theoretically have to do a 2 to 3 hour stop at fourty feet, but they don't the water is too cold and what not, instead they surface with no stops and in less than five minutes get unsuited and go in a chamber to decompress at 40f. Which is normal practice for that kind of diver.
My question is, why do most diving manuals suggest that if a mistake was done, take the diver to the clossest chamber and put him on o2. Why not if the mistake was identified early (Emergency Ascent) just grab a new bottle and reg and go back down to i don't know 36f or 40f if not only 30, stay there for 10 to 15mn (considering the dive wasn't supposed to be a decompression dive) and then ascend and just monitor the diver, even then bring him to a chamber. At least the bigger bubles would have, due to the pressure, gotten smaller and with the prolongued stay would have had time to exite the blood stream or the tissue.
Or am i completly missing something? i honestly don't understand. I do know that a lot of what if's would have to come into play, and maybe that's why they don't say you can do it... it would have to be under 5mn, a no deco dive etc...
If anybody can help?

Under most USN protocols, the longest decompression occurs in the sub-60' range.

In order to get ships out of harms way particularly when divers are working in combat zones, get divers out of the 'hostile' envrionment of the water ASAP, and that deco schedules were not entirely reliable for the type of diving USN divers do, SUR-D protocol were the norm ... surface decompression. In chambers, the DSO has full control over the divers, and are able to complete the required decompressions and treat DCI if it were to occur, all in a dry controlled environment of the chamber.

In-water recompression is not recommend for recreational divers except in emergencies [when recompression chambers are gauranteed multiple hours away, such as diving in remote Pacific islands] for recreational divers because, per standard DAN teachings: risk for drowing and death due to unconsciousness or seizures are greater than any disability caused by DCI.

Recreational divers are truly not trained for breathing high pp02 mixes in the water and breathing air has poor results for in-water recompression. For more information, see Richard Pyle's articles on in-water recompression.

http://www.scubaboard.com/t43583.html

 

[jviehe]

Good point on getting ships out of harms way. Navy divers arnt in the water for recreation. Just never thought of the fact that you need to get the divers out and the ship moving.

 

[ScubaSarus]

Don't forget there is oxygen readily available to the diver at the chamber and medical professionals.

 

[MikeFerrara]

There is a big difference between missed or omited decompression and in water recompression

In water recompression as treatment fo a diver who is bent is generally not recommended for all the reasons mentioned above by others however it has been done successfully and may be the only option in remote locations. It's risky and you need to be equiped for it.

Missed or ommited decompression
Every decompression class that I know of teaches procedures for this. If you miss decompression time for whatever reason (like taking an injured diver to the surface or whatever) and you are sympton free there are procedures for dropping back down and completing decompression. If you skip 40 minutes of O2 deco at 20 ft by popping to the surface for whatever reason, you go back and do the deco if you have gas and are able. There's a real good chance you're toast if you don't.

These procedures aren't taught in recreational training because there should be no manditory decompression and if there is it's likely only a little. In this case the recommendation is generally to stay out of the water, monitor for symptoms and breath O2.

 

[Dr Deco]

Hello Scuba Board Readers:

Deck Decompression

Military and commercial divers seldom will decompress in the water if there is a long decompression and another option available. For decades, it has been standard practice to decompress in a bell that was placed at the depth of the first Haldane stop.

Another option is to perform surface decompression by extending the forty-foot stop, on oxygen, and then coming directly to the surface. The diver then doffs is diving equipment, and within five minutes enters a deck decompression chamber (DDC) and is taken back down to forty feet of pressure. The diver will then complete the decompression in the DDC. The divers are told to keep activity to a minimum while on the surface.

This is planned decompression and is not an emergency situation. The diver is safe and warm and can be observed. Because all DDCs will have a man-lock, medical personnel can enter if needed. Divers are kept warm, can eat, perform personal hygiene, and be protected if a storm arises.

Recreational Divers

If a recreational diver misses decompression, in-water recompression can be attempted, but this has its own problems. Mike Ferrara mentioned that a procedure is taught by some agencies; I was not aware of that.

Assuming that the decompression is less than 20 minutes, it is possible to simply wait on the boat, move minimally, and breathe oxygen if available. Because tables are quite liberal, probably little will happen. There is naturally no guarantee; it is best to avoid this situation. Certainly, strenuous activity should be avoided, as this will only engender the growth and/or generation of nuclei.

As the missed time increases, an in-water contingency is becoming necessary (as mentioned in the post above). This assumes that you have the necessary gas [which you should have in any case].

Dr Deco :doctor:

 

[letoktok]

it all makes sense, i did mean a missed due to accident, (getting tangled with a lift bag or helping an other diver etc...)
so it is possible with restrictions. Thanks for the info, it allways good to know.

 

[MikeFerrara]

Hello Scuba Board Readers:

Deck Decompression

Recreational Divers

If a recreational diver misses decompression, in-water recompression can be attempted, but this has its own problems. Mike Ferrara mentioned that a procedure is taught by some agencies; I was not aware of that.

Assuming that the decompression is less than 20 minutes, it is possible to simply wait on the boat, move minimally, and breathe oxygen if available. Because tables are quite liberal, probably little will happen. There is naturally no guarantee; it is best to avoid this situation. Certainly, strenuous activity should be avoided, as this will only engender the growth and/or generation of nuclei.

As the missed time increases, an in-water contingency is becoming necessary (as mentioned in the post above). This assumes that you have the necessary gas [which you should have in any case].

Dr Deco :doctor:

Just to clearify...

I was refering to planned decompression dives where one or more stops are missed. In this case the required decompression is often way more than 20 minutes. I wasn't at all sugesting that a recreational diver who goes a little past the "NDL" and then finds themself at the surface should go back down.