Need Help with Article on Getting Bent

[JonG1]

Question for boulderjohn do u suffer with sea sickness at all

 

[Dominik_E]

But with a PFO bubbles can bypass the lungs and end up on the arterial side so even if they are micro and would have been sub clinical the risk is increased of damage.

The first part is certainly true, a PFO can shunt bubbles. But it is far from the only shunt a human can have. The shunted fraction is very small, so anyhow the "target" tissues would still have to be prone to bubbling. And in the end, what matters is not appealing theories of how causal chains can look, but hard data. If anything, I personally find the fact that so many divers have a PFO, so little incidents occur, and that the theory behind PFOs causing hits is so appealing rather worrying.

 

[michael-fisch]

Sure a closure is still a risk, and the dangers of any elective surgery have to be carefully assessed. For several buddies and others tec divers that I have spoken to over the last 20 years, the risks were worth it, and they are quite happy with the result.
As far as the people who have died while having their PFO fixed, I have neither heard about them nor do I know any of them.
I remember a Tec Instructor at Lake Garda years ago, who after several DCS 2 incidents had a PFO test (TEE) done and had her PFO fixed only to find out the hard way several months later, that she also had a shunt in her lungs.
Haven't heard about her doing any further diving in the last 15 years since the shunt diagnosis.
Instead of doing TEEs as the gold standard, for detecting a right-left cardial shunt, why don't we do Trancranial Dopplers (TCD), again with the shaken bag of 0.9% NaCl - that way we would detect the presence of any shunt in a much less invasive manner than the TEE and it's a lot cheaper since any doctor (probably including a doctor of literature) with an 8 or 10Mhz doppler can do it.

Surface O2 is a treatment form somewhere between Chamber, IWR, and sleeping off the minor pains of a mild DCS. It's usefull, but if you have a significant DCS2 bend you will still need other treatment in addition to surface O2. I really believe that that article in Wetnotes was written for their main customer base of teaching recreational instructors/divemasters and has nothing to do with those of us who are doing 3+ hour dives deeper than 90M.

Michael

 

[JonG1]

Dominik I am familiar with the lung shunt and I seem to recall that heart plumbing can be reversed? What others are there pls

 

[michael-fisch]

Russian roulette has a risk of 1 in 6, right? Even if one blankly buys the famous factor of 4 greater DCS risk with a PFO, it is still less than 1 in 1000. And a chamber ride will not fix a bullethole in the head. This comparison is misguided.

You are right, but you are wrong on whatever your rish factors are. The navy exceptional exposure tables accept a 3% risk of DCS, and thats for younger and exceptionally fit navy divers with a BMI and age much lower than the general diving public. Technical dives are often "balls to the wall" and the only reason we get away with them is because we learned over years of technical diving what works for us, instead of the total knowledge that a trimix instructor with less than 10 trimix dives to his credit can give us in a weekend course. I despise rec>tec instructors and am very happy that I got my instruction over the years from some of the very best instead of from those who decided that learning how to teach tec is a great way to put food on the table when the pool of rec students isn't keeping you fed.
Michael

 

[Dominik_E]

With relevance to arterialisation of bubbles, I would think various forms of shunts in the heart and the lung, yes. With regard to testing, all tests involve injecting bubbles, so there is a small risk. And a TCD will not show the exact location of the heart shunt, so if you want it closed you will still need a TTE, right? I am a physicist, not a physician, so someone more familiar with closing PFOs would have to comment on the risk of the closing procedure, but I would strongly think it is higher than 1 : 1000 for some adverse outcome.

To say you do not know someone who died from the procedure is not statistics. You also do not know someone who died from having a PFO. At most you will suspect it, but this will be biased. This debate is quite old, and what I think is striking is that divers are much more convinced of the relevance of PFOs than the medical scientific literature seems to be.

As maybe a starting point: one of the moderators here, Simon Mitchell, has written several highly cited papers about medical aspects of decompression. From his postings, it seems he is also an avid technical wreck diver with dives way beyond 100m. He stated his views and some citations here:

Going tech - Patent Foramen Ovale (PFO) testing?

Is a highly interesting thread to read!

 

[Germie]

Sure a closure is still a risk, and the dangers of any elective surgery have to be carefully assessed. For several buddies and others tec divers that I have spoken to over the last 20 years, the risks were worth it, and they are quite happy with the result.
As far as the people who have died while having their PFO fixed, I have neither heard about them nor do I know any of them.
I remember a Tec Instructor at Lake Garda years ago, who after several DCS 2 incidents had a PFO test (TEE) done and had her PFO fixed only to find out the hard way several months later, that she also had a shunt in her lungs.
Haven't heard about her doing any further diving in the last 15 years since the shunt diagnosis.
Instead of doing TEEs as the gold standard, for detecting a right-left cardial shunt, why don't we do Trancranial Dopplers (TCD), again with the shaken bag of 0.9% NaCl - that way we would detect the presence of any shunt in a much less invasive manner than the TEE and it's a lot cheaper since any doctor (probably including a doctor of literature) with an 8 or 10Mhz doppler can do it.

Surface O2 is a treatment form somewhere between Chamber, IWR, and sleeping off the minor pains of a mild DCS. It's usefull, but if you have a significant DCS2 bend you will still need other treatment in addition to surface O2. I really believe that that article in Wetnotes was written for their main customer base of teaching recreational instructors/divemasters and has nothing to do with those of us who are doing 3+ hour dives deeper than 90M.

Michael

No, they really talk about technical diving. Most sportsdivers/recreational divers don't have access to pure oxygen. So it is really better to do surface oxygen than to get it tested or closed. I have the article at home. And I am sure they talk about technical diving and not about recreaional diving (the magazine is 95% for technical divers).
But you can get yours closed while I will stay diving without limits by taking some oxygen (I hope never get bent). Closure will hold you out of the water between 1 week and 6 months (there is also somewhere an article about divers who could not wait till they are cleared to dive again and they all didn't had any negative things about going diving 'too' early.) It is also not spoken about DCS, but only how to avoid dcs. So if you get bent, then surface oxygen will only help as first aid. But if you are not bent, it will help against getting bent. A big big difference.
And testing is not needed if there is no reason (more than one time bent and surface oxygen doesn't help).
In my eyes divers look too much at a pfo as the root cause. That is not true. There are also other shunts and sometimes it is really just a pity.

 

[boulderjohn]

Question for boulderjohn do u suffer with sea sickness at all

Not at all.

 

[bakodiver391]

Does anyone know if there are fewer unexplained hits on RBs in comparison with OC given the optimisation of ppo2 across the dive.

In our operation we only keep records for 1 year then destroy them, so I can only give my impression on what happens at Bikini over 9 years and thousands of logged man dives. The answer is no, there are not fewer unexplained hits on RB. Again, only my impression, but I think the computer algos give you full credit for the optimal PPo2 so that safety buffer is eliminated. Coupled with the typically longer run times on rb, the higher exposure results in slightly more incidence of DCS.

 

[Cert1967]

I haven't got a clue what I would do differently in the future.

Maybe see an expert? When you return home you might consider seeing Dr. Thombs at PSL.

Physician Detail

Paul A. Thombs, MD, is a board certified physician specializing in Undersea and Hyperbaric Medicine. Dr. Thombs practices at the Hyperbaric Medicine Center at Presbyterian/St. Luke's Medical Center and Rocky Mountain Hospital for Children at P/SL in Denver, Colorado. He received his MD from the University of Colorado Denver. Dr. Thombs continued his training with the San Diego Sports Medicine and Arthroscopy fellowship program in California. He completed additional fellowships at the Navy Sub School Navy DVG Salvg School in Florida and St. Luke’s Medical Center in Milwaukee, WI. In addition, Dr. Thombs has written publications on hyperbaric oxygen treatment.​

From the PADI Med Form

ENDORSERS
Paul A. Thombs, M.D., Medical Director Hyperbaric Medical Center
St. Luke’s Hospital, Denver, CO, USA​

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