2 DCS hits and a PFO closure

[Duke Dive Medicine]

This is a picture of what I get on a regular basis, sometimes on other area's of my body, usually shoulders and backs of the arms. Now that's what you do see.
Shortness of breath and pain in the chest making it hard to breath is worse.
All usually dissapates within 24 hours.
Now the pain in the Base of my back and neck that crackles when you twist normally takes 3 to 5 days to ease.
One day I'll take myself to the chamber.

What I think is all these bends must be fairly minor all beit a little inconvenient as the body repairs itself ready for the next bout the next time you dive. Think a lot of it has been over dramatised. The body is just telling you to take it easy.

I hope.

That is your body telling you that something is wrong. Please consider listening.

Best regards,
DDM

 

[Kevrumbo]

Our advice to divers with PFO is to avoid diving, but we generally see those divers after they've had DCS and we've had them tested. What were you being worked up for when you were tested?

Assuming that you plan to continue diving: Provided you're otherwise healthy, if you haven't had DCS yet then I would say continue to dive conservatively, e.g. high conservatism settings on the computer, padding deco where it's prudent as you have. Closure at this point is probably not a reasonable thing to do.

Best regards,
DDM

There are medical-legal issues here to begin with for @vladodessit. For further tech training with GUE, he's going to need a consult with a Cardiologist anyway, and obtain a medical release if warranted for recreational diving with mandatory decompression procedures, if he has known diagnosis of a PFO.

The better more practical advice -assuming he's planning on taking the course locally here in Los Angeles- is to initially talk to GUE Instructor Karim Hamza about all concerns diving, and the chances of being cleared under GUE policy to undergo further training with a known PFO condition.

 

[Dr. Doug Ebersole]

Wow! I fly out of town for a couple of days and this thread really takes off.

First of all, I agree completely with all of the excellent information provided to this thread by Duke Dive Medicine.

My thoughts --

1. Probably 25% of the population has a PFO. It is NOT a disease, it is a "normal variant". All of us have a PFO as a fetus and a newborn. It directs blood coming from the placenta over to the left side of the heart, bypassing the lungs which are collapsed and full of fluid, to then be pumped to the body. When we are born and the lungs open up, this flap closes and in about 75% of people it completely seals over the first couple of years of life. However, in 25% of people it never completely seals.

2. The problem with DCS is the inert bubble load, not the PFO. Anything a diver does to decrease his or her inert gas load will lower the risk of DCS. Shallower dives, shorter dives, fewer dives per day, diving nitrox on air profiles, long safety stops, etc are all very effective approaches in decreasing the risk of DCS in any diver whether or not there is a PFO. In decompression diving the risk of DCS (with our without PFO) is higher due to the higher inert gas load, but the same principles apply. Fewer dives per day, conservative gradient factors, doing extra decompression beyond what is required, etc. should all be helpful to some degree.

3. Yes, PFOs increase the risk of DCS by something like 5-fold but this is an increase in the RELATIVE risk. The ABSOLUTE risk of DCS is still very small with a PFO. For argument's sake, if the risk of DCS in recreational diving is about 2 episodes per 10,000 dives and a PFO increases this risk 5-fold, the ABSOLUTE risk of DCS in recreational divers with a PFO is still only 1 per 1000 dives. PFO closure is a relatively low risk procedure (especially compared to a lot of other procedures I do on a daily basis) but the risk of some sort of complication is still 2-3% or so -- bleeding, palpitations, etc. Hence, the medical community DOES NOT recommend assessing divers for PFO and definitely DOES NOT recommend routine closure of PFOs.

4. PFOs are associated with certain types, but not all types of DCS -- cerebral, spinal, skin bends, and inner ear. If someone is having, say, recurrent joint (type 1) bends after diving and is found to have a PFO, the two are "true, true, and unrelated". That diver should NOT have a PFO closure

5. Though arguably controversial, PFO closure in SELECTED INDIVIDUALs is REASONABLE in my opinion. Those divers would be ones that do not want to give up diving, are already diving as conservatively as they can, and have had recurrent "unexpected" DCS, especially severe neurologic cases. I always discuss with the diver three options --
a. Stopping diving
b. Conservative diving
c. PFO closure

6. PFO closure DOES NOT prevent DCS. The best case scenario after PFO closure is that the diver has his or her risk of DCS reduced to the baseline risk of a diver without a PFO and this would only occur if the PFO contributed to the symptoms which is never completely known. It's a "best guess" based on history, exam, echo results, etc.

7. The screening test of choice (not just my opinion but by consensus statements from Undersea and Hyperbaric Medical Society and South Pacific Underwater Medicine Society) is a transthoracic (from the chest wall) echocardiogram with injection of agitated saline through a peripheral vein ("bubble study"). Yes, transesophageal echo is more likely to detect a small PFO than is a transthoracic echo but it is much more invasive in that it requires intravenous sedation and a probe being passed down the esophagus. I reserve transesophageal echo for divers in whom I REALLY think they have a PFO contributing to their symptoms but the transthoracic echo is of poor quality. As mentioned above, a transcranial doppler (agitated saline injected into a peripheral vein and then a probe positioned over the temporal artery) can detect right to left shunting of bubbles but cannot localize where the problem is -- intracardiac, intrapulmonary, etc. For this reason, a transthoracic echo is felt to be a better screening tool.

Dr. Petar Denoble and I are still recruiting for a DAN sponsored study prospectively following divers with PFO and DCS, whether or not they opted for closure of the PFO. The link for more information is www.dan.org/pfostudy. We would greatly appreciate anyone and everyone that would like to participate.

 

[Kevrumbo]

Wow! I fly out of town for a couple of days and this thread really takes off.

First of all, I agree completely with all of the excellent information provided to this thread by Duke Dive Medicine.

My thoughts --

1. Probably 25% of the population has a PFO. It is NOT a disease, it is a "normal variant". All of us have a PFO as a fetus and a newborn. It directs blood coming from the placenta over to the left side of the heart, bypassing the lungs which are collapsed and full of fluid, to then be pumped to the body. When we are born and the lungs open up, this flap closes and in about 75% of people it completely seals over the first couple of years of life. However, in 25% of people it never completely seals.

2. The problem with DCS is the inert bubble load, not the PFO. Anything a diver does to decrease his or her inert gas load will lower the risk of DCS. Shallower dives, shorter dives, fewer dives per day, diving nitrox on air profiles, long safety stops, etc are all very effective approaches in decreasing the risk of DCS in any diver whether or not there is a PFO. In decompression diving the risk of DCS (with our without PFO) is higher due to the higher inert gas load, but the same principles apply. Fewer dives per day, conservative gradient factors, doing extra decompression beyond what is required, etc. should all be helpful to some degree.

3. Yes, PFOs increase the risk of DCS by something like 5-fold but this is an increase in the RELATIVE risk. The ABSOLUTE risk of DCS is still very small with a PFO. For argument's sake, if the risk of DCS in recreational diving is about 2 episodes per 10,000 dives and a PFO increases this risk 5-fold, the ABSOLUTE risk of DCS in recreational divers with a PFO is still only 1 per 1000 dives. PFO closure is a relatively low risk procedure (especially compared to a lot of other procedures I do on a daily basis) but the risk of some sort of complication is still 2-3% or so -- bleeding, palpitations, etc. Hence, the medical community DOES NOT recommend assessing divers for PFO and definitely DOES NOT recommend routine closure of PFOs.

4. PFOs are associated with certain types, but not all types of DCS -- cerebral, spinal, skin bends, and inner ear. If someone is having, say, recurrent joint (type 1) bends after diving and is found to have a PFO, the two are "true, true, and unrelated". That diver should NOT have a PFO closure

5. Though arguably controversial, PFO closure in SELECTED INDIVIDUALs is REASONABLE in my opinion. Those divers would be ones that do not want to give up diving, are already diving as conservatively as they can, and have had recurrent "unexpected" DCS, especially severe neurologic cases. I always discuss with the diver three options --
a. Stopping diving
b. Conservative diving
c. PFO closure

6. PFO closure DOES NOT prevent DCS. The best case scenario after PFO closure is that the diver has his or her risk of DCS reduced to the baseline risk of a diver without a PFO and this would only occur if the PFO contributed to the symptoms which is never completely known. It's a "best guess" based on history, exam, echo results, etc.

7. The screening test of choice (not just my opinion but by consensus statements from Undersea and Hyperbaric Medical Society and South Pacific Underwater Medicine Society) is a transthoracic (from the chest wall) echocardiogram with injection of agitated saline through a peripheral vein ("bubble study"). Yes, transesophageal echo is more likely to detect a small PFO than is a transthoracic echo but it is much more invasive in that it requires intravenous sedation and a probe being passed down the esophagus. I reserve transesophageal echo for divers in whom I REALLY think they have a PFO contributing to their symptoms but the transthoracic echo is of poor quality. As mentioned above, a transcranial doppler (agitated saline injected into a peripheral vein and then a probe positioned over the temporal artery) can detect right to left shunting of bubbles but cannot localize where the problem is -- intracardiac, intrapulmonary, etc. For this reason, a transthoracic echo is felt to be a better screening tool.

Dr. Petar Denoble and I are still recruiting for a DAN sponsored study prospectively following divers with PFO and DCS, whether or not they opted for closure of the PFO. The link for more information is www.dan.org/pfostudy. We would greatly appreciate anyone and everyone that would like to participate.

Doc @debersole , @Duke Dive Medicine and @mattia_v : After reading about @Pullnglide 's account on the Cave Diver's Forum, I don't believe that suffering multiple incidents of type II DCS as a morbid way of discovering you have a PFO is either desirable or ethical -Don't you agree??? (Especially in a locale like North Florida Cave Country where there's a dearth of Recompression Chambers willing to treat recreational divers with emergent cases of DCI)

Preventative screening by simple non-invasive contrast Trans Cranial Doppler, will at least rule out any gross Right to Left Intracardiac Shunt, and help to make a vital informed decision for a prospective technical diving student whether the increased risk of DCI due to a PFO condition is worth undergoing mandatory decompression dive training.

 

[mattia_v]

Preventative screening by simple non-invasive contrast Trans Cranial Doppler, will at least rule out any gross Right to Left Intracardiac Shunt, and help to make a vital informed decision for a prospective technical diving student whether the increased risk of DCI due to a PFO condition is worth undergoing mandatory decompression dive training.

Until there is solid evidence that the benefit of screening outweighs the risk, no. Just as preventive screening CT or MRI scans in healthy, asymtopatic individuals are bad medicine and bad science from an epidemiological perspective. The quality and usability of a test as a diagnostic or screening tool depends on a number of factors.

As mentioned above, DCS is rare. Very severe DCS rarer still. And a PFO is really quite common. Screen 100 tech divers and you'll find 25 with a PFO. Closure is not a simple, no-risk procedure (incidence of complications is very low, but non-zero; so is your risk of DCS) and entails some cost and questionable benefit.

 

[Kevrumbo]

Tell this to the OP @Pullnglide :

Until there is solid evidence that the benefit of screening outweighs the risk, no. Just as preventive screening CT or MRI scans in healthy, asymtopatic individuals are bad medicine and bad science from an epidemiological perspective. The quality and usability of a test as a diagnostic or screening tool depends on a number of factors.

As mentioned above, DCS is rare. Very severe DCS rarer still. And a PFO is really quite common. Screen 100 tech divers and you'll find 25 with a PFO. Closure is not a simple, no-risk procedure (incidence of complications is very low, but non-zero; so is your risk of DCS) and entails some cost and questionable benefit.

@debersole and @Duke Dive Medicine :
In making the diagnosis of the cause of illness in an individual case, calculations of probability have no meaning. The pertinent question is whether the disease [or disorder] is present or not. Whether it is rare or common does not change the odds in a single patient. ... If the diagnosis can be made on the basis of specific criteria, then these criteria are either fulfilled or not fulfilled. — [A. McGehee Harvey, James Bordley II, Jeremiah Barondess]

If you knowingly undertake decompression diving with a PFO, then you are at least aware of what the potential risks are. Take extra precautions like plannng your deco profiles very conservatively, and making sure there is immediate access to a Recompression Chamber nearby -or else give up technical diving altogether especially if there is no Chamber Facility nearby (i.e. North Florida Cave Country). . .

 

[mattia_v]

Tell this to the OP @Pullnglide :
@debersole and @Duke Dive Medicine :
In making the diagnosis of the cause of illness in an individual case, calculations of probability have no meaning. The pertinent question is whether the disease [or disorder] is present or not. Whether it is rare or common does not change the odds in a single patient. ... If the diagnosis can be made on the basis of specific criteria, then these criteria are either fulfilled or not fulfilled. — [A. McGehee Harvey, James Bordley II, Jeremiah Barondess]

If you knowingly undertake decompression diving with a PFO, then you are at least aware of what the potential risks are. Take extra precautions like plannng your deco profiles very conservatively, and making sure there is immediate access to a Recompression Chamber nearby -or else give up technical diving altogether especially if there is no Chamber Facility nearby (i.e. North Florida Cave Country). . .

We're not discussing the diagnosis of illness, so the quote above has no bearing here. It's also only true for tests that are near-perfect; risk stratification (probabilistic calculations) can tremendously improve your diagnostic yield for tests that do not have excellent sensitivity AND specificity (i.e. most of them), and understanding of the epidemiology is necessary for correct interpretation.

You're advocating testing for a fairly poorly characterised risk factor for DCS in asymptomatic, healthy individuals. The question here is purely one of risk assessment; you have a 1:4 chance of having a PFO, and if you do, this may mean nothing (most small PFO likely entail no additional risk, although again, the evidence is slim), or may mean you have a 1:1000 chance (based on population evidence) of developing a condition. This changes if you place yourself in a higher risk category by actually having developed unexplained DCS. And even in this group, the value of finding a small PFO remains a little unclear, but that's just medical practice as we know it.

 

[Pullnglide]

Great post Dr. Ebersole! I've filled out all of the information and included my dive logs as well as a copy of your report and I'll mail it out today for your DAN PFO study. Thanks again!

 

[kensuf]

I don't think it should be recommended for all divers but it's definitely something for someone doing deeper and longer decompression dives to think about. A TEE wasn't that bad but was expensive and a lot of people have insurance with high deductibles and may not have the financial resources to be tested. I'm not a Dr. and not well versed enough to offer any facts. From what I know a lot of it is all hypothesis. All I know is I've had 2 neurological DCS hits so I chose to have it closed. The future will tell the tale for me.

I've had two TEE's in my life and tested negative both times, the only thing I had to show for them was a sore throat. My PFO, which was causing me to get frequent cases of cutis marmorata, was closed in 2014. A TTE showed that PFO really existed.

Go figure?

 

[Pullnglide]

I've had two TEE's in my life and tested negative both times, the only thing I had to show for them was a sore throat. My PFO, which was causing me to get frequent cases of cutis marmorata, was closed in 2014. A TTE showed that PFO really existed.

Go figure?

If I remember correctly you have not had another incident since the closure. From what I understand my PFO was large. I don't know how it compares to most the Dr. sees as far as size goes but I know the same size device was used as used in the majority of closures.