Alert Diver article "Free-Flow" flaw

[VTernovski]

ok, I am actually disgusted and appalled by the DAN's Alert Diver magazine (November /December 2003 issue)'s article called "Free-Flow"..

sorry if this is a bit dated, but I just accidentally ran into this article.... the article describes middle aged male getting bend after his regulator had a free flow and got to the surface from 125ft in one minute... and then go on and on how those types of equipment rare and so on... hello?!! they also mentioned that after that dive he did multiple free dives to 35ft... and then not a word, not even a thought that this may have something to do with him getting bend... I am so disappointed in DAN and the author who claims to be DAN Medical Information Specialist yet had nothing to address the issue that he got bent precisely because he did a free dive right after his rapid ascent, and especially after he already experienced initial symptoms. There is a reason we don’t free dive after scuba diving! this is thoroughly explained by George Irvine here, and is also a common sense if you don't know anything about dive medicine.

 

[fins wake]

I haven't read the original Alert Diver article. but certainly a very rapid ascent from depth could in itself be sufficent for DCI. Do note that initial symptoms were described as being present after the initial and aborted scuba dive ...

Although I don't regard Mr Irvine as a decompression authority or dive medical authority (but indeed as a world-class cave diver) I'd tend to agree that rapid - albeit short - bounce dives after the initial dives probably won't alleviate any symptoms, and may very likely aggrevate them (and in some instances may even cause them in the first place). In this particular instance, we won't know.

In any case, it doesn't really sound as if the article as described is enough to invoke feelings of disgust etc. I assume the lesson as usual is - at the very least - not to reenter the water again if experiencing symptoms of DCI, but to inhale oxygen and seek medical advice/treatment.

 

[BigJetDriver]

----certainly a very rapid ascent from depth could in itself be sufficent for DCI. Do note that initial symptoms were described as being present after the initial and aborted scuba dive ...

Although I don't regard Mr Irvine as a decompression authority or dive medical authority (but indeed as a world-class cave diver) I'd tend to agree that rapid - albeit short - bounce dives after the initial dives probably won't alleviate any symptoms, and may very likely aggravate them----

----the lesson as usual is - at the very least - not to reenter the water again if experiencing symptoms of DCI, but to inhale oxygen and seek medical advice/treatment.

Fins, et al,

Your point is a good one. Ascent rate, by itself, may very well trigger DCS symptoms, depending upon your inert gas loading.

As for anyone experiencing DCS and diving again, except for IWR, all one can say is: "AAARRRGGHH!!!!"

The problem, as usual with good ole' George, is not that he's wrong here. His delivery style ("I'm George! I'm Super-mensch! It doesn't happen to me! It happens to all of you toads!") masks an important message. Short bounces or free-dives CAN in fact bring about the very effect he describes.

For a more accurate, sensible, and scientific discussion of this effect I can recommend "Diving Medicine" by Bove, "Diving and Subaquatic Medicine" by Edmonds, Pennefather, Lowry, et al, and "Diving Physiology in Plain Engllish" by Jolie Bookspan. You will get an accurate picture of the situation without the GI3 hand-job!

BJD :anakinpod

 

[pipedope]

Most of the bad cases of DCI that I know about personally have involved a diver who did deep or repeatative dives and then did a bounce (free the anchor) or free dives afterward.

 

[Dr Deco]

Hello Readers:

Diving with DCS

I do not have the article mentioned, but gather from the responses that an individual went diving after having symptoms of DCS. If correct, this was certainly not a good idea, as responders mentioned.

The quick, deep dive following a longer diver (or series of dives) has been known to precipitate cases of neurological DCS. It has been mentioned by many that this is not a wise thing to do. An anchor that requires freeing should be attended to by someone other than the divers (a crew member, for example).

Additionally, as mentioned, the rapid ascent could have been a factor in the problem. Such ascents allow nuclei to rapid expand (Boyle’s law effect) and the Laplace pressure is quickly reduced. Dissolved nitrogen enters into the now-expanded bubble and stabilizes it at a larger diameter. The same effect is seen when you rapidly unscrew the cap from a bottle or carbonated beverage as contrasted with the gentle release of pressure. The amount of dissolved carbon dioxide in both bottles is almost identical, but the degree of effervescence is remarkable different.

Dr Deco :doctor: