2 embolisms

[Nuribromanski]

Hi Nuribromanski,

I don't think that. I read the Mobile Diver's post and can only assume that he did not perform deco as he did not write about deco stops.

You know, just a hunch, but were you with Mobile Diver (you seem to be protesting too much!)? Why are you protesting so much...

Look, divers do you use Nitrox as a washout gas while staying within NDL. It is not unheard of. I own a computer that lets me use 3 different EANX gases on a single dive. It is a recreational computer.

markm

i was definitely not there, lol. but it seems strange ppl are asking questions that show they arent reading what OP actually wrote...not sure how useful that is 4 analysis. example, someone asked about SI between these two dives...uh, OP said: same site, similar dives...almost 1 yr apart!

if rec diver was bringing 50% (technical gas mix btw, more than 40%) for NDL washout, and also staged O2 for same purpose...yeah, that would be pretty unheard of 2 me. i read OP as saying yes he had deco but it was only shallower stops, yet he altered plan due to possibile surface condition and got on his 50% at 70ft to begin decoing. then got up 2 shallows and found conditions favorable enough to finish deco on O2. guess he could be clearer, but assuming what u r doesnt make sense 2 me.

 

[Freewillow]

Thank you treasurehunter and Fabio for the explanations. Help me again because I am french speaking and english can be difficult to understand.

For me Bends come from an excess of nitrogen in the tissue that creates embolisms in the blood streal or in the Tissues and can create symptoms.


A.G.E. on the other hand is caused by the fact that you go up too rapidly without exhaling sufficiently. Therefore you have "overpressure" and "air" that goes trough your pulmonary arteries. that can create problems, similar to BENDS but with very different origins.

This was the reason for my first questionning. BENDS OR AGE.

Am I crazy?

 

[fsardone]

Thank you treasurehunter and Fabio for the explanations. Help me again because I am french speaking and english can be difficult to understand.

For me Bends come from an excess of nitrogen in the tissue that creates embolisms in the blood streal or in the Tissues and can create symptoms.


A.G.E. on the other hand is caused by the fact that you go up too rapidly without exhaling sufficiently. Therefore you have "overpressure" and "air" that goes trough your pulmonary arteries. that can create problems, similar to BENDS but with very different origins.

This was the reason for my first questionning. BENDS OR AGE.

Am I crazy?

Bends was the caisson workers malady and it was called like that because to seek relief from pain those pour souls where lying with the major articular joints bent to seek relief.

What you are talking about is traumatic gas embolism which is caused by overpressure of the lungs during ascent holding your breath. This in turn is surely a source of AGE but might cause pneumotorax (collapse of a lung due to air between the pleuras causing uncoupling of the lung from the chest wall).

Decompression will cause bubbles in the tissues. Blood is a tissue. This will happen both in the arterial flow and in the venous flow. There will be more in the venous flow because it cames out from the rest of the tissues. Less or minimal in the arterial because the lungs will filter the bubbles out.

If you have a shunt in the heart blood will bypass the lung filter
If you have a shunt in the lungs these will be unable to eliminate bubbles
If you have an overpressure in the lungs gas can enter directly in the bloodstream.
These are the cases in which you have AGE and you have more bubbles there hindering decompression since arterial blood will be unable to pickup gas coming out of the rest of the tissues.

In any decompression (reduction of ambient pressure NOT staged decompression) you have microbubbles in the bloodstream ...
If you keep the oversaturation within reasonable limits the bubbles will stay small, will be filtered by lungs and you will be simptoms free ...

Cheers

Fabio

 

[markmud]

Bends was the caisson workers malady and it was called like that because to seek relief from pain those pour souls where lying with the major articular joints bent to seek relief.

What you are talking about is traumatic gas embolism which is caused by overpressure of the lungs during ascent holding your breath. This in turn is surely a source of AGE but might cause pneumotorax (collapse of a lung due to air between the pleuras causing uncoupling of the lung from the chest wall).

Decompression will cause bubbles in the tissues. Blood is a tissue. This will happen both in the arterial flow and in the venous flow. There will be more in the venous flow because it cames out from the rest of the tissues. Less or minimal in the arterial because the lungs will filter the bubbles out.

If you have a shunt in the heart blood will bypass the lung filter
If you have a shunt in the lungs these will be unable to eliminate bubbles
If you have an overpressure in the lungs gas can enter directly in the bloodstream.
These are the cases in which you have AGE and you have more bubbles there hindering decompression since arterial blood will be unable to pickup gas coming out of the rest of the tissues.

In any decompression (reduction of ambient pressure NOT staged decompression) you have microbubbles in the bloodstream ...
If you keep the oversaturation within reasonable limits the bubbles will stay small, will be filtered by lungs and you will be simptoms free ...

Cheers

Fabio

Hi Fabio,

Thanks for your posts. I am learning from your posts and enjoying them.

Question: I had assumed that AGE was primarily caused by holding your breath while ascending (I think freewillow is asking the same thing).

You have written about shunts. What is a "shunt"?

Is it an abnormality? Can a shunt be associated with a DCS issue?

Or, is there a different way to get AGE while performing a "textbook" decompression (either NDL or staged)?

I know you have explained this already, but I did not understand your point.

Thanks again for your informed opinion.

markm

 

[Pinecube]

I believe what you are thinking of is "Lung Overexpansion Injury" when you hold your breath and ascend. That is a separate issue from Arterial Gas Embolism (AGE).
I found this post to be helpful in explaining the difference between DCS and AGE.


Mobile Diver: If I'm reading it right, your dive was meant to be longer (possibly with decompression stops and such) but was cut short due to the anchor dragging? Otherwise I'm left wondering why your friend would risk doing a similar dive to one that had given him a DCI hit before. Either way, are there any steps that you'll be taking to make sure you'll be safe if you do a similar dive and find that your anchor is dragging again?

 

[fsardone]

Hi Fabio,

Thanks for your posts. I am learning from your posts and enjoying them.

Question: I had assumed that AGE was primarily caused by holding your breath while ascending (I think freewillow is asking the same thing).

You have written about shunts. What is a "shunt"?
Is it an abnormality? Can a shunt be associated with a DCS issue?
Or, is there a different way to get AGE while performing a "textbook" decompression (either NDL or staged)?
I know you have explained this already, but I did not understand your point.
Thanks again for your informed opinion.

markm

Markm,

Pinecube post above and linked post explains all in good details.
About shunts, these are 'defects' that allow venous blood to bypass the alveoli where the bubbles are filtered.

Cardiac shunt is generally a patent oval foramen: a hole between the two ventricoli that allows blood bypass (this is normal in pre-birth babies and it is supposed to close at birth, it does not always happen)

Pulmonary shunt: is a bypass in lung blood circulation allowing part of the blood bypassing the alveoli and going direct from the arterial to venous circulation (remember that oxygenated status is reversed in small pulmonary circle) without being oxygenated and de-bubbled first.

Cheers

Fabio

 

[markmud]

I believe what you are thinking of is "Lung Overexpansion Injury" when you hold your breath and ascend. That is a separate issue from Arterial Gas Embolism (AGE).
I found this post to be helpful in explaining the difference between DCS and AGE.


Mobile Diver: If I'm reading it right, your dive was meant to be longer (possibly with decompression stops and such) but was cut short due to the anchor dragging? Otherwise I'm left wondering why your friend would risk doing a similar dive to one that had given him a DCI hit before. Either way, are there any steps that you'll be taking to make sure you'll be safe if you do a similar dive and find that your anchor is dragging again?

Hi Pinecube,

Thanks for your response. Yeah, I get that in OW training. What I did not understand were the relationships between a shunt and AGE. And, are shunts caused by diver error or a physiological anomaly.

Your link was beautiful!! Thanks for that. Posts #2 and #3 explained it. TSANDM had the best response and was very succinct in laymen's terms (this is why she was so respected in the diving community).

TSANDM: "BEAUTIFUL post, BubbleTrubble! I have absolutely nothing to add, except to emphasize two things: Although both AGE and DCS can be prevented, DCS CAN occur in people who have stayed entirely within their no-deco limits, and have executed safe ascents. It is important to know that there is no shame in having it or reporting it. Life-threatening DCS is extremely rare in recreational divers who have stayed within their safe diving limits.

AGE, on the other hand, except for very rare occasions involving underlying medical problems, involves errors in technique, and DOES occur in recreational divers executing shallow dives (including pool dives!). And the damage done by AGE may not be treatable. Thus the very heavy emphasis in training on never holding your breath. Although this is an oversimplification of what you really need to do, you will be SAFE following that edict. "

Thanks again to fsardone. You answered my questions about shunts! If shunts caused the incidents in question, both divers have birth defects (I assume the Pulmonary Shunt is also an anomaly and not caused by an incident).

markm

 

[Duke Dive Medicine]

Anyone can shunt bubbles through the pulmonary circulation, it's not necessarily related to a defect. That's one of the reasons why vigorous exercise after diving is discouraged.

Best regards,
DDM

 

[fsardone]

Thanks again to fsardone. You answered my questions about shunts! If shunts caused the incidents in question, both divers have birth defects (I assume the Pulmonary Shunt is also an anomaly and not caused by an incident).

markm

Hi Markm,
I used defect in quotes because, as DDM pointed out, it is not necessarily caused by a birth defect or anatomical defect, it might be caused by excercise post dive or overpressuring your thoracic cavity (breath holding/valsalva manoeuvre) post dive when you have a lot of VGE and alveoly are working at capacity to get rid of the bubbles.
Any perturbation of the pressure balance, speed of the blood stream can allow bubbles to go through the sieve of the lungs and become AGE.

If you want to dive (pun intended) in this you could read a very long thread on CCREXPLORERS.
Simon Mitchell is an hyperbaric doctor and rossh is the author of Vplanner/multideco.
you could start from beginning but is from here where the discussion deepend on VGE/AGE and bubbles #70 Also here #79 and the subsequent post contains a wealth of interesting details.

Cheers

Fabio

 

[Mobile Diver]

i was definitely not there, lol. but it seems strange ppl are asking questions that show they arent reading what OP actually wrote...not sure how useful that is 4 analysis. example, someone asked about SI between these two dives...uh, OP said: same site, similar dives...almost 1 yr apart!

if rec diver was bringing 50% (technical gas mix btw, more than 40%) for NDL washout, and also staged O2 for same purpose...yeah, that would be pretty unheard of 2 me. i read OP as saying yes he had deco but it was only shallower stops, yet he altered plan due to possibile surface condition and got on his 50% at 70ft to begin decoing. then got up 2 shallows and found conditions favorable enough to finish deco on O2. guess he could be clearer, but assuming what u r doesnt make sense 2 me.

Again, thanks much for actually reading the post.

---------- Post added September 30th, 2015 at 11:29 AM ----------

I believe what you are thinking of is "Lung Overexpansion Injury" when you hold your breath and ascend. That is a separate issue from Arterial Gas Embolism (AGE).
I found this post to be helpful in explaining the difference between DCS and AGE.


Mobile Diver: If I'm reading it right, your dive was meant to be longer (possibly with decompression stops and such) but was cut short due to the anchor dragging? Otherwise I'm left wondering why your friend would risk doing a similar dive to one that had given him a DCI hit before. Either way, are there any steps that you'll be taking to make sure you'll be safe if you do a similar dive and find that your anchor is dragging again?

You are reading it right. Neither of us altered our diving in any way since we made hundreds of dives like this before & after. Probably never know why this happened.

---------- Post added September 30th, 2015 at 01:46 PM ----------

Couple of other points:
1) My research says 3-4 minute onset + 1 side paralysis = AGE by far the most likely cause.
2) Since some asked - my computer uses Buhlmann ZLH16 algorithm. Not that it makes any difference.