Can freediving cause DCS?

[rafacuatic]

I suffered 3 DCS spearfishing.All in a 25-30m and 2'30-3 min range.So no too deep....Shorts intervals in surface + deshidratation+too tired, may be the cause.
Rafa

[dotey]

iam glad i came across this post i learn something new everyday thank you guys for putting this here for us to read

[ricki]

I had three high nitrogen alarms on my Oceanic Geo while doing free dives between about 105 and 125 ft. among a bunch of other dives within that range and less. Surface intervals were ten minutes or more as a rule with the last SCUBA dive being about a month before. The meter is back with Oceanic right now as I don't quite understand what to think or necessarily do, if the alarm goes off again.

I am not certain how vetted the deco algorithm is for free diving or more particularly, residual nitrogen remaining from SCUBA and free diving. Elected not to do that later regardless of what the meter might have to say about it btw. Too many minor hits in my past and unusual stories of accidents when mixing residual N from SCUBA and free diving for my liking.

[unobreath]

Originally Posted by Mullins

Given this, it seems a bit unwise to suggest DCS is unlikely. An "I don't know" sounds much more accurate?

Also, it's not a 'what if'. That example is quite a similar to how I would actually be training were I not worried about DCS risk. I'm going to train CW this weekend - would you suggest I tried it? I hope not.

this is for you...this is a doctor performing a doppler on a freediver who made a dive to 165 meters. A doppler, if you do not know what it is, is used to fin bubbles in your body. It is 100% the only way to know for sure your residual nitrogen in your blood.

CASE STUDY
By: Dr Hossam Nassef
(Head of Patrick’s medical team)

As Patrick Musimu started training for his record, Deco International offered him and his team Hyperbaric Medical support as medic first aid evacuatrion was already secured by the search and rescue (SAR) team. And as Patrick and I spoke, I found out that he conducted one deep breath-hold dive every third-fourth day and still breathed pure oxygen for one hour after the exposure to reduce the amount of the build-up nitrogen that all breath-holders expect to have after repeated relatively shallow exsposures or more dramatically after a very deep single exposure. He even spoke about chamber rides during the course of his training for nitrogen washout and as I was not that much convinced with the harmful excess of nitrogen in the tissues of breath-hold divers and as we already had research going on with a team of cardiologists measuring bubbles in the hearts of SCUBA divers.

I took the team together with the portable Doppler echosounder on Patrick's boat and did a bubble count on him upon completion of his 165 meters dive after 5,25,45,60 minutes successively and amasingly the maximum number of bubbles that was found in his systems was found in the right heart and he had only 2 bubbles every third beat while his security SCUBA team who dived on air and mixed gases showed tens of silent bubbles up to 1 hour after they surfaced and of course still had no symptoms! So the whole team concluded that Patrick was absolutely at NO risk of DCS following his single deep exposures even down to 200 meters and I even suggested that he stops normobaric oxygen breathing after his trials to avoid the harmfull effect on the lungs even at this minimal dose. Upon arrival to the base, Patrick performed a lung function test and all the functions and capacities of his lungs were found normal.

here's the link: H2O Magazine - Spring 05

now that is why I say it is unlikely to get DCS from freediving. Still possible but unlikely.

[trux]

Originally Posted by unobreath

this is for you...

NO risk of DCS following his single deep exposures even down to 200 meters ...

Yet, after his attempt to 209.6 m, he experienced severe DCS symptoms, was transported to hospital, and treated in a hyperbaric chamber. Because of the problems they called off the planned final dive, made just a shallow simulation for the press, and told that the last training dive was the record instead.

[trux]

And as for the Doppler measurements of circulating bubbles, Dr. Ralph Potkin, who is an expert on freediving physiology, working at the Beverly Hills Center for Hyperbaric Medicine, Los Angeles, California, also did research using the Doppler method. Just he did it little bit more systematically than Dr. Nassef, and with a bigger group of breath-hold divers. Strangely, he has a quite different opinion than you, or than Dr. Nassef:

Dr. Potkin's three research areas address issues of considerable practical concern for freedivers. DCS used to be thought of as an issue for scuba divers, but Dr. Potkin's Doppler measurements have made it clear that there is a real, though as yet unquantified exposure for apnea divers as well. As performance parameters increase and more freedivers dive deeper and longer this issue will very likely become of greater concern to more people.

[jome]

Should be pointed out that Patrick didn't pack...Which potentially makes a huge difference

[unobreath]

Originally Posted by trux

Yet, after his attempt to 209.6 m, he experienced severe DCS symptoms, was transported to hospital, and treated in a hyperbaric chamber.

Severe DCS is very serious. Usually life threatening and is not resolved in one treatment. Most people that have severe type 2 DCS symptoms end up having a lot of nerve damage and sometimes paralyzed. I do not doubt that he may have gotten a slight type 1 hit or even a little scare, but I doubt it was "severe" as many if not all people do not dive again after a severe case of type 2 DCS. there is not a severe type 1 as type 1 is not life threatening and usually only takes 1 treatment table to clear up with a few HBO's afterward to make sure there are no reoccurring symptoms.

[laminar]

Couple of things:

1. I think that the general opinion that freedivers are not at risk of the bends contributes to the lack of reporting of such suspected incidents. I know of examples of local divers having symptoms of the bends. In one case, the diver thought it couldn't possibly be the bends and it went untreated for quite a while. I think if DCS was presented as a very real risk we would have more cases reported and the actual incidence of DCS would fall someone between the two. Also, since most freedivers (my assumption, here) are not necessarily trained scuba divers, they wouldn't immediately recognize DCS symptoms, as often trained scuba divers I imagine would rather not admit that they've been bent, but a dive master probably would take the safe route? I think lack of awareness makes it difficult to make a claim that freedivers don't often get bent.

2. I think we also have to admit that the rules for DCS in freediving may be completely different. Eric has already mentioned that surface interval and lung volume may have had little to do with his DCS, but rather it was ascent rate. We are so far away from having sort of chance of developing deco tables - how many dives are needed to supply the raw data? Probably will never happen. Also, as Trux mentions, a lot of other bizarre things are happening to the body in apnea that could worsen or lessen DCS.

3. I met Dr. Potkin at the 2004 World Championships in Vancouver, BC. He was conducting tear film tests on many competitive freedivers and the safety divers running the comp. Trux, do you know if he's reported those findings officially in a study? I do remember him being surprised that almost all of us had significant microbubbles in our tear film. Several of the safety freedivers made 30-60 dives to 30-15m with approx 7 minutes of interval, whereas the competitive divers made usually only 2-3 dives in a day, with one max dive.

Pete

[trux]

Originally Posted by unobreath

Severe DCS is very serious. Usually life threatening and is not resolved in one treatment. Most people that have severe type 2 DCS symptoms end up having a lot of nerve damage and sometimes paralyzed.

Such cases do exist in freediving too. Permanent neurological damage is not uncommon among native professional freedivers (i.e. ama), but we also know it in competitive freediving too. The best known are the cases of Benajmin Franz (Germany), who is paralyzed since his freediving DCS accident in 2002, and the accident of the Venezuelan world recordman Carlos Coste last year, who got severely hit, suffered a brain damage, and despite getting the best available treatment, it took many months before he recovered.

Some of the quoted documents list dozens of DCS cases among amas, freedivers, and spearfishers (for example Decompression Sickness in Breath-Hold Diving by Robert M. Wong - a study of 101 freediving DCS cases). It includes cases of complete paralysis and death.

So please stop spreading and advocating your baseless and false suggestions about low risk of DCS. Backing it with your claim being an expert in the field (that we are unable to verify, because you remain anonymous), you act very dangerously. Spreading such false theories may endanger health and life of freedivers who would rely on your "expertize".

[trux]

Originally Posted by laminar

Eric has already mentioned that surface interval and lung volume may have had little to do with his DCS, but rather it was ascent rate.

I do not think this is the right interpretation. The ascent rate certainly matters a lot, and likely can cause a DCS alone, but the other factors still play an important role too. For example the study of 101 freediving DCS cases made by Wong (included in this document) shows that DCS was the most frequent at freedivers diving below 20m for a period over 3 hours, and with short surface intervals (highest risk at intervals shorter than the apnea). Of course, the ascent rate is very important even in such cases, but not the only factor. It's importance it higher at deep freediving with very few dives - then the influence of the other factors is limited.

The above linked document by Dr. Wong also mentions the work of Dr. Schaefer who observed foam in venous and arterial blood drawn immediately after a BH diver surfaced from a single dive, lasting one and a half min to 27m. Similar measurments using the Doppler method by other researchers did not show any bubble formation after single dives to similar depth. That likely confirms Eric's words - probably in that very case the diver ascended faster than at the other later measurments. Unfortunately, I did not yet see a study where the ascent speed was measured.

Originally Posted by laminar

He was conducting tear film tests on many competitive freedivers and the safety divers running the comp. Trux, do you know if he's reported those findings officially in a study?

Well, there is another document about tear tests in my database, bu it is by Dr. Sheard. I know about the work of Dr. Potkin, I also know he did Doppler measurments on freedivers. The work is often referred and quoted, but I did not find it published anywhere. If you happen to have a contact to Dr. Potkin, please let him know that we would love to see it. If he does not want publishing it to the wide public, but would agree having it accessible by confirmed freedivers only, I could place it on my server where it could be accessed only by registered members who passed a strict theory test.

[unobreath]

Originally Posted by trux

So please stop spreading and advocating your baseless and false suggestions about low risk of DCS. Backing it with your claim being an expert in the field (that we are unable to verify, because you remain anonymous), you act very dangerously. Spreading such false theories may endanger health and life of freedivers who would rely on your "expertize".

First, I never told you that you wouldn't get bent and I did say it was possible. You have taken this to the personal level where writing on forums are not suppose to go but usually end up that way. What I say is my OPINION and I am entitled to it. If you don't want to hear it then don't log on and read it. Last time I checked this was a forum and not a medical journal. This is the reason I remain anonymous. You take someone's opinion who happens to be very knowledgeable in the area and you find on the internet a case study that says the exact opposite, I could find hundreds of case studies that support my opinion but what's the point as they are just a doctors interpretation of their findings. The fact of the matter is that getting bent and not getting bent is not written in stone. Some people on their first time diving will get bent, then the guy that has been diving fro 20 years has never gotten bent. If you take the ratio of people who dive to the ones that get bent. The number is very small. Meaning it is possible yet unlikely.You read my post then come back with a completely different take on what I am saying. It is an opinion get over it. I told you I was very knowledgeable in the area of DCS and diagnosing it, I gave you example after example of DCS, types of DCS, other diving related illnesses and even told you some symptoms and so on and so on. I never said I was a doctor or that I am an expert in freediving physiology. And as to false theories, [EDIT(sanso):removed insult] You are relying on googling "DCS in freediving" where I have first hand knowledge of diagnosing it and treating it. At the end of the day You are just some ignorant dude on a forum who doesn't know jack shit about DCS but would rather google it then post your results on here. At the end of the day I am the one who treats [EDIT(sanso): beep] like you in a chamber when you do get bent. I figured you would have been mature and respected my opinion as a fellow freediver but your last post just shows your true character as a person. Dont come to hawaii and get bent, as I will surely lose all my knowledge of diving related illnesses the second you step foot in the chamber. Have a nice day. And oh yeah one more thing just in case you forgot. IT'S MY OPINION! So please stop whining about DCS. You get bent you get bent. Its not an exact science. The sooner you figure that out the better.

[trux]

Well, I ignore your invectives, because you are apparently not controlling yourself, but let's speak to the topic:

Originally Posted by unobreath

... The fact of the matter is that getting bent and not getting bent is not written in stone. Some people on their first time diving will get bent, then the guy that has been diving fro 20 years has never gotten bent. ...

That's something I'd agree with, but do not think it is consistent with your claim that "DCS at freediving is unlikely". It is unlikely only if you respect the rules - surface intervals, dive time, ascent rates,... If you do not respect them, you may get hit pretty likely. That's the point I am trying to make since the beginning.

[cdavis]

Both of you guys need to chill.

Trux, you have been beating unobreath over the head for 4 pages, point made, enough!

Unobreath, your comments about Trux are obnoxious and have no place in this forum. Go somewhere else if you can't do any better.

Connor

[efattah]

Originally Posted by unobreath

You are relying on googling "DCS in freediving" where I have first hand knowledge of diagnosing it and treating it.

Well, YOU are just a third party who treats and diagnoses it. You have never been bent from freediving. So I would say the we who HAVE been bent while freediving are a FAR GREATER authority than your theories and hypotheses.

I accumulated dives profiles from more than 100 of my own personal dive sessions without DCS and 8 personal sessions with DCS, and by correlating them, made some real conclusions which I know for me are far more relevant than some abstract theories put forward by someone who has never even experienced the problem personally.