Young and not bent

[dothanfrogman]

Agian I say who cares? If you want the liability risk then take it. It is your call but my idea is you get O2 you get the doctors too.;-0

 

[Dr Deco]

Dear Readers:

Oxygen

I have been following the development of this thread for the past day, and, from the viewpoint of physiology, would like to offer these comments.

• There is not any “bends/no bends” limit, but rather it is a progression of bubble growth associated with the nitrogen “dose.”
• If the nitrogen dose were sufficient, all decompressions would develop into a case of DCS (assuming that micronuclei were present).
• Breathing oxygen will speed the off gassing of dissolved nitrogen and than in bubbles also.
• This unloading occurs whether or not you have a few bubbles or many bubbles.
• You can assist nitrogen elimination by breathing oxygen.
• Some tech divers breath oxygen during the shallow stops, some breathe it on the surface (“the hidden stop”), and some breathe it on the boat. They do this whether or not they have DCS.
• Oxygen will not “mask” symptoms; it is not an anesthetic or any other type of anodyne (pain reliever).
• Symptoms, even neurological, can remit spontaneously; in the old days, this type of regression was the only recourse a diver had.
• Symptoms can remit with or without oxygen, but I would head for a chamber in any case.

This deals only with the physiology - the legal aspect is another issue.

For those who would care to read more, here is a reference for a technical library:
Dick AP, Massey EW. Neurologic presentation of decompression sickness and air embolism in sport
divers. Neurology 1985 May;35(5):667-71

Dr Deco :doctor:

 

[The Chairman]

Dear Dr. Deco and readers...

I hope that I did not overstep my authority here, but I had to delete many posts, some of them obvious sockpuppets and all them completely off topic. It is against the TOS of this board to harrass other board members. If you have an issue with someone from another board, PLEASE keep it on that board. DO NOT assume another identity in order to systematically assassinate someone's character. No, the person who you were attacking did not ask for help... but I got a complaint from another board member about it, and have to agree with them. Please feel free to stay and contribute, but do not feel free to vent on another board member. If you have ANY questions or comments (positive or negative) concerning this, please PM me OFF of this thread. Any posts not concerning this topic will be deleted immediately. If you want to really gripe to the world about this or even support it, then head over to Site Support and do it there!

 

[MikeFerrara]

Dr Deco,
If O2 can't mask symptoms, why does DAN very clearly state that they think it can? Is there more to it ? Are they wrong? I know decompression is not an exact science but this seems like a direct cantrdiction. I have read their comments and have spoken to them and asked simple direct question. Did I still misunderstand and mis-state their position?
Mike

 

[Genesis]

I grilled Dan Noord about this after Celia said the same thing initially to me.

I think there's some misunderstanding WITHIN DAN on some of this stuff. Dan Noord did not comment that O2 could "mask" symptoms. He DID say that it may delay the onset of symptoms, but as I pointed out to him, its almost never the case that this would be bad, since if I delayed the onset of symptoms from when I'm on the deck of the boat until we dock two hours later I've just put myself where I can get immediate EMS attention if it becomes necessary. That's a good thing, not a bad one, and I might have reduced the severity of the hit at the same time.

He DID say that they believed that some people would perhaps be inhibited in believing they needed to be monitored (or that they took a hit at all) by thinking they had "fixed it", and that was the essence of their concern.

The other thing I brought up with Mr. Noord is that promulgating the idea of "grabbing the bottle triggers a medical chain of action" as a policy statement is potentially harmful, in that it may inhibit people from tending to grab the O2 when they otherwise would (and perhaps should!) There already appears to be some issue, if you read the reports, with people being in denial about having DCS - certainly, compounding that by delaying the use of O2 in the event of a blown profile can't help things. Since DAN's view is that you should never withhold O2 from somoene who believes they need it, there appears to be an inherent conflict between those two points of view.

Where I think Mr. Noord and I left it, and this, perhaps, needs more discussion (especially in how you put this in a cogent statement of position), is that if something is going to trigger the "need" (e.g. "medical recommendation") to be monitored (whether by others around you or formally by a physician) it should be the blown profile - not the decision to consume (or not) O2.

 

[Alban]

Over here ( which may be different ) if either myself or a diver has cause for concern over a dive then they should immediately be put on O2 . I am then duty bound to inform the coast guard , they then contact a medical doctor with the details of signs symptoms if any and the profile of the dive missed stops ect , it would then be the doctors decision what action to take , they inform the cast guard and the duty manager decides on the means of rescue. I am also bound to have enough O2 to last until help arrives where I dive it is a 20 min response time. The coast guard has always maintained they would prefer to be contacted in all situations and at no time should anyone feel they are wasting their time.

Dr Deco has said before there is an increased risk of dcs it is not a hit no hit situation and I think that is what causes the problems . If you have missed only a few mins of deco as opposed to 20 or 30 mins you probably evaluate this yourself but the question is "in that situation should you make that decision " ? Here at least for legal reasons you should not

Yours Alban

 

[Dr Deco]

Dear Readers:

Interesting thread - - -

This thread has created quite a bit of comment from the many readers. I believe that most who read this FORUM are getting the picture that DCS is not an “all or nothing” phenomenon. There is a progression from “silent bubbles” (a term from 1943) all the way to very severe problems and even death. Fortunately, death is very rare in diving.

Types of DCS

We should also bear in mind that the manifestations of DCS depend on the tissues (or organs) in which the gas phase appears . This means, for example, that a gas phase in muscle tissue probably produces nothing (or possibly the feeling of fatigue). Fat tissue is also without pain, but (as with muscle) it can produce a big bubble load in the veins and eventually the heart and lungs. With a PFO, this could be dangerous.

Gas in tendons or ligaments manifests itself as joint pain (“the bends”).

A gas phase in the spinal cord will present as weakness or paralysis in both arms or both legs. You might also get paraesthesia (e.g., numbness, tingling).

In the brain, the problem will be one or cognition, speaking, or possibly weakness (or paralysis) on one side of the body (e.g., right arm and right leg).

Two at Once :boom:


The bad news is that a manifestation of DCS indicates that something went wrong that day. The nitrogen dose was too large, or too many micronuclei formed, or surface tension was low because of dehydration (and a concomitant concentration of surfactants), or muscular activity produced increased gas loads (or sleeping during the surface interval reduced washout of nitrogen). It is thus possible to find more than one problem at a time.

”Masking” of Symptoms

Oxygen will not really “mask” symptoms. The most commonly employed “masking” agents are beverage alcohol and aspirins. Divers will finally appear at a chamber hours after a frank problem and confess to self medication for “the flu.”

What, I believe, DAN fears is that, seeing one problem gone, the diver now feels s/he is fine. But, a real possibility is that only joint pain has remitted, but neurological problems are developing. A delay in traveling to a chamber means a few more nerve cells die than was necessary. Treatment is now very costly and may not be completely successful. ;-0

Dr Deco :doctor:

 

[The Iceni]

blackwater once bubbled...
lucky that diving outside the profile didn't lead to DCI, yes.

for the O2, . . . it also would start a course of treatment which might require continuation to compleation.

I apologise if I am repeating something that has already been discussed in one of those extremely long posts on this thread.

Guys, can someone tell me what is inherently wrong with the prophylactic use of surface oxygen i.e. as a preventer of DCI?

In my opinion it should always be used after a dive if there is even the slightest suspicion of a risk of DCI.

Alban and blackwater highlight the problem. It is a medicolegal one.

At present it would seem that there has to be a very high threshold of risk before the O2 bottle is broken out of its case. This then consitutes "an incident" together with the apparently inevitable mobilisation of the emergency services and a possible visit to a recompression chamber.

Does this make sense, given our current state of knowledge? I think not.

There will be incidents where the major violation of deco requirements will make an incident highly likely, in which case it is quite appropriate to send a mayday call even before any symptoms appear.

However I would aver that there are far, far more numerous occassions when the violation is marginal and the above may not be at all necessary.

As I understand it, the decision the hypebaric physician makes on whether to recompress someone is based on the history of the magnitude of any deco violation together with the casualty's reported symptoms (and clinical findings). He is unlikely to make that decision with confidence over the radio and will iniviatbly err on the side of caution.

If the diver reports any symptoms at all, particularly if they are helped by oxygen clearly this must be treated as an incidence of DCI, for the reasons given by Dr Deco.

In Pos-tech's case no symptoms at all were reported and he did not receive surface oxygen. He was lucky, as he could have, in which case the immediate use of 100% oxygen alone could have been sufficent to prevent any symptoms from developing, being curative.

I suspect there will be many, many occassions falling into the latter category, when that unpredictable fine line betweeen what would have constituted an (unexpected?) incident of DCI could be prevented, or the development of pathology would be delayed, by the early use of surface oxygen.

I would suggest that it would make a great deal of sense to lower the threshold for the use of surface oxygen, allowing asymptomatic divers who believe they may be at minimally increased risk to use it "just in case", rather than reserve its use for "incidents" with an inevitable chain of events that follow.

As Genesis has suggested, often oxygen may not have been given, when it should have been, because of the strong peer pressure one feels not wanting to be a nuisance and the cause of an incident. This leads to the dangerous phenomenon of "denial".

So Genesis, having reread your posts thoroughly, I'm with you all the way!

I admit my background allows me to do this but I often use 100% oxygen from my stage bottle, solely as a precaution, when climbing the ladder and for a minute or two following certain dives if only because I have access to it, having already used it for my shallower stops.

Does this constitute an "incident" each and every time and why does it need to become an incident if another asymptomatic diver (who does not have access to his own deco gas) wishes to avail himself of it, or indeed that special cylinder in the sealed box?

 

[TwoBitTxn]

pos-tech once bubbled...
. I did not take o2 because I shoewed no sighns of dcs. am I just very lucky?????????

He didn't take O2.

A couple points I have. Medical O2 in the states is considered a drug. An EMT can administer O2 in an emergency.

IMHO.... There is nothing wrong with prophylactic use of O2. Its already used that way by properly trained divers.

TwoBit

 

[The Iceni]

TwoBitTxn once bubbled...
. . . Medical O2 in the states is considered a drug. An EMT can administer O2 in an emergency.

IMHO.... There is nothing wrong with prophylactic use of O2. Its already used that way by properly trained divers.

TwoBit

Hi Two bit,

You were too quick for me!

Yes, but only for medical treatment of an established incident!

Since oxygen is not a medicine when used for decompression underwater, how can it be a medicine when used for decompression on the surface?

Perhaps that's the real problem?

I feel a poll comng on!