Can divers with a PFO, still dive on O2 CCR?

RonMicjan · 26th June 2007, 17:02

bending goats with O2? what books are you guys reading?

Thanks for the input, will pass it on.

hchoat · 26th June 2007, 18:26

I am thoroughly dismayed at this thread.

Regarding Oxygen bends, reference the following:
K.W. Donald Oxygen Bends in the Journal of Applied Physiology (you can find the paper yourself).

Further- you should be aware that there is no clear agreement in the hyperbaric medical community that PFO is a contraindication to diving. Divers have latched on to a few papers and taken it as the gospel....

The Deco Stop

babar · 26th June 2007, 21:08

Quote: (Originally Posted by hchoat)

I am thoroughly dismayed at this thread.
Further- you should be aware that there is no clear agreement in the hyperbaric medical community that PFO is a contraindication to diving. Divers have latched on to a few papers and taken it as the gospel..

Exactly right!

RonMicjan · 27th June 2007, 00:17

Quote: (Originally Posted by hchoat)

I am thoroughly dismayed at this thread.

Regarding Oxygen bends, reference the following:
K.W. Donald Oxygen Bends in the Journal of Applied Physiology (you can find the paper yourself).

Further- you should be aware that there is no clear agreement in the hyperbaric medical community that PFO is a contraindication to diving. Divers have latched on to a few papers and taken it as the gospel....

The Deco Stop

why dismayed? (To cause to lose enthusiasm; disillusion) What about this thread would cause emotional distress or disillusionment?

I am aware that a PFO is not a guaranteed contraindication to diving, there are many degrees of PFO, my friends doctor, however, told him to stay out of the water, but said doctor may not be aware of the O2 rebreather option.
Thanks for the reference, I had never heard of bending on O2.

were you being snippy, or am I perceiving something incorrectly?

the only reason I go onto TDS, is specifically to harass perrone ford...friend of yours?

back on the subject maybe?

Diver Dave · 27th June 2007, 05:16

Hey Ron
Good question. I know a Dr. that runs the chamber here at UCLA and will ask him. Also, Run it by Dr. Deco, Micheal Powell PhD. He can be found some where on SCUBABOARD.COM . He is a Physiologist with NASA and is very interesting and well informed. Also found this guy after a quick search. Doc's Diving Medicine Home Page This should beat all of the opionions.
Good luck
David

dteubner · 27th June 2007, 07:07

Quote: (Originally Posted by Diver Dave)

Hey Ron
Good question. I know a Dr. that runs the chamber here at UCLA and will ask him. Also, Run it by Dr. Deco, Micheal Powell PhD. He can be found some where on SCUBABOARD.COM . He is a Physiologist with NASA and is very interesting and well informed. Also found this guy after a quick search. Doc's Diving Medicine Home Page This should beat all of the opionions.
Good luck
David

David,

There are at least half a dozen hyperbaric physicians who dive rebreathers who are regular contibuting members. Not all opinions are necessarily uninformed.

Dave T

teksimple · 27th June 2007, 16:54

From Nitrox FAQ

Is it possible to get an oxygen bend?

Yes, but in practical terms it can be ignored. To get an oxygen bend you'd have to go well beyond all of the guidelines, omit a substantial amount of decompression obligation and be lucky enough not to have had an acute oxygen toxicity attack during the dive.
Experiments carried out on goats at the Admiralty Experimental Diving Unit (AEDU) in 1945 demonstrated that oxygen bends are possible. The tests were based on immediate decompression (at 75 feet/min) to atmospheric pressure after one hour at the maximum depths (PO2 > 2.0 Bar). Severe bends resulted including pulmonary oedema and bubble embolism - identical to those caused by nitrogen. The symptoms disappeared within 10 to 15 minutes demonstrating that these were indeed oxygen bends. The oxygen was metabolised by the body. One out of seven occurrences did not clear up naturally and required recompression for a full cure. Note that this procedure included substantial amounts of missed decompression and was at partial pressures well above the maximum recommendations for nitrox diving.

For a closed circuit diver with greater oxygen exposure than a nitrox diver, oxygen bends is *practically* impossible. However--since we apparently are talking theory here--I will suggest one type of closed circuit diver where oxygen bends is a distinct possibility: the "vitally challenged" diver. Among the vitally challenged, oxygen metabolism is very reduced, if nonexistent. Oxygen seizure, arterial gas embolism and/or explosive *inert* gas decompression likely precipitated the qualifying event for loss of diver vitality.

I suspect that a goat's unique physiology probably contributes to the ability to develop oxygen bends without prior oxygen seizure. Goats are one of those animals that synthesize their own ascorbic acid (Vitamin C).

To summarize, challenged vitality is perhaps not a contraindication to oxygen bends, but it is certainly a contraindication to posting in this forum.

RonMicjan · 27th June 2007, 17:18

Thanks for the note Tek, no wonder I was ignorant of the subject, its a non-issue. Only so much room in my brain, must keep it loaded with relevant stuff, like how to make hollandaise sauce for my eggs bennie

"in the unlikely event of an oxygen bend..." wait 15 minutes.

teksimple · 27th June 2007, 20:14

Quote: (Originally Posted by RonMicjan)

Thanks for the note Tek,

I guess no one got my deadpan humor. "Vitally challenged"=deceased=dead.

Diver Dave · 27th June 2007, 22:36

Hey Ron
These are the thought from the doc at the UCLA chamber.

First, most people with PFO's dive (most don't know they have it and it is very common). It doubles the risk of DCS (but to a still low number). We don't routinely look for it unless someone has an undeserved or severe case of the bends or is repeatedly bent.

That said, diving on pure O2 should decrease the risk of getting bent, with or without a PFO. I will check into this to see if anyone has studied it (it's really a good thought).

Not anything spectacular but if he comes up with any additional info, I will post it.

David

26th June 2007, 17:02	#11 (permalink)
RonMicjan Cap Ron scourge of the NW Current Rebreather/s: Megalodon Dolphin Home Build Other Rebreather/s: Sport Kiss Classic Kiss Dolphin Home Build Join Date: Feb 2005 Location: Cape Disapointment, The Graveyard of the Pacific Posts: 1,083	Re: Can divers with a PFO, still dive on O2 CCR? bending goats with O2? what books are you guys reading? Thanks for the input, will pass it on. __________________ Ron "Life is pain princess, anyone who tells you different, is selling something", The Dread Pirate Wesley. www.tmishop.com Diving bits etc.
(Online)

26th June 2007, 18:26	#12 (permalink)
hchoat Resident Selkie Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2005 Location: Pensacola, FL- USA Posts: 227	Re: Can divers with a PFO, still dive on O2 CCR? I am thoroughly dismayed at this thread. Regarding Oxygen bends, reference the following: K.W. Donald Oxygen Bends in the Journal of Applied Physiology (you can find the paper yourself). Further- you should be aware that there is no clear agreement in the hyperbaric medical community that PFO is a contraindication to diving. Divers have latched on to a few papers and taken it as the gospel.... The Deco Stop __________________ Duct tape is like the force... it has a light side and dark side, and it holds the universe together. Last edited by hchoat : 26th June 2007 at 18:34.
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26th June 2007, 21:08	#13 (permalink)
babar Curmudgeon Current Rebreather/s: Evolution Sport Kiss Other CCR Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Other CCR Join Date: Apr 2005 Location: Southern California Posts: 420	Re: Can divers with a PFO, still dive on O2 CCR? Quote: (Originally Posted by hchoat) I am thoroughly dismayed at this thread. Further- you should be aware that there is no clear agreement in the hyperbaric medical community that PFO is a contraindication to diving. Divers have latched on to a few papers and taken it as the gospel.. Exactly right! __________________ Babar Evolution Plus Sport kiss
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27th June 2007, 00:17	#14 (permalink)
RonMicjan Cap Ron scourge of the NW Current Rebreather/s: Megalodon Dolphin Home Build Other Rebreather/s: Sport Kiss Classic Kiss Dolphin Home Build Join Date: Feb 2005 Location: Cape Disapointment, The Graveyard of the Pacific Posts: 1,083	Re: Can divers with a PFO, still dive on O2 CCR? Quote: (Originally Posted by hchoat) I am thoroughly dismayed at this thread. Regarding Oxygen bends, reference the following: K.W. Donald Oxygen Bends in the Journal of Applied Physiology (you can find the paper yourself). Further- you should be aware that there is no clear agreement in the hyperbaric medical community that PFO is a contraindication to diving. Divers have latched on to a few papers and taken it as the gospel.... The Deco Stop why dismayed? (To cause to lose enthusiasm; disillusion) What about this thread would cause emotional distress or disillusionment? I am aware that a PFO is not a guaranteed contraindication to diving, there are many degrees of PFO, my friends doctor, however, told him to stay out of the water, but said doctor may not be aware of the O2 rebreather option. Thanks for the reference, I had never heard of bending on O2. were you being snippy, or am I perceiving something incorrectly? the only reason I go onto TDS, is specifically to harass perrone ford...friend of yours? back on the subject maybe? __________________ Ron "Life is pain princess, anyone who tells you different, is selling something", The Dread Pirate Wesley. www.tmishop.com Diving bits etc.
(Online)

27th June 2007, 05:16	#15 (permalink)
Diver Dave New Member Current Rebreather/s: Dolphin Home Build Other Rebreather/s: Dolphin Home Build Join Date: Mar 2006 Location: So California Posts: 9	Re: Can divers with a PFO, still dive on O2 CCR? Hey Ron Good question. I know a Dr. that runs the chamber here at UCLA and will ask him. Also, Run it by Dr. Deco, Micheal Powell PhD. He can be found some where on SCUBABOARD.COM . He is a Physiologist with NASA and is very interesting and well informed. Also found this guy after a quick search. Doc's Diving Medicine Home Page This should beat all of the opionions. Good luck David __________________ "You F##k up, you die!" A quote from a big Jamacian instructor at my first discover SCUBA experience back in 84. It kept me on the ball then and it still works for me today. Diver Dave of So Calif
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27th June 2007, 07:07	#16 (permalink)
dteubner Pedant Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Mar 2005 Location: Adelaide, Australia Posts: 216	Re: Can divers with a PFO, still dive on O2 CCR? Quote: (Originally Posted by Diver Dave) Hey Ron Good question. I know a Dr. that runs the chamber here at UCLA and will ask him. Also, Run it by Dr. Deco, Micheal Powell PhD. He can be found some where on SCUBABOARD.COM . He is a Physiologist with NASA and is very interesting and well informed. Also found this guy after a quick search. Doc's Diving Medicine Home Page This should beat all of the opionions. Good luck David David, There are at least half a dozen hyperbaric physicians who dive rebreathers who are regular contibuting members. Not all opinions are necessarily uninformed. Dave T __________________ Dave T Hanlon's Razor - Never attribute to malice that which can be adequately explained by stupidity.
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27th June 2007, 16:54	#17 (permalink)
teksimple Enlightened Alpinist Current Rebreather/s: Sport Kiss MK 15.X Other Rebreather/s: Sport Kiss Classic Kiss Join Date: Apr 2005 Location: Back in Hawaii Posts: 495	Re: Can divers with a PFO, still dive on O2 CCR? From Nitrox FAQ Is it possible to get an oxygen bend? Yes, but in practical terms it can be ignored. To get an oxygen bend you'd have to go well beyond all of the guidelines, omit a substantial amount of decompression obligation and be lucky enough not to have had an acute oxygen toxicity attack during the dive. Experiments carried out on goats at the Admiralty Experimental Diving Unit (AEDU) in 1945 demonstrated that oxygen bends are possible. The tests were based on immediate decompression (at 75 feet/min) to atmospheric pressure after one hour at the maximum depths (PO2 > 2.0 Bar). Severe bends resulted including pulmonary oedema and bubble embolism - identical to those caused by nitrogen. The symptoms disappeared within 10 to 15 minutes demonstrating that these were indeed oxygen bends. The oxygen was metabolised by the body. One out of seven occurrences did not clear up naturally and required recompression for a full cure. Note that this procedure included substantial amounts of missed decompression and was at partial pressures well above the maximum recommendations for nitrox diving. For a closed circuit diver with greater oxygen exposure than a nitrox diver, oxygen bends is practically impossible. However--since we apparently are talking theory here--I will suggest one type of closed circuit diver where oxygen bends is a distinct possibility: the "vitally challenged" diver. Among the vitally challenged, oxygen metabolism is very reduced, if nonexistent. Oxygen seizure, arterial gas embolism and/or explosive inert gas decompression likely precipitated the qualifying event for loss of diver vitality. I suspect that a goat's unique physiology probably contributes to the ability to develop oxygen bends without prior oxygen seizure. Goats are one of those animals that synthesize their own ascorbic acid (Vitamin C). To summarize, challenged vitality is perhaps not a contraindication to oxygen bends, but it is certainly a contraindication to posting in this forum. __________________ ---- _____________ "I don't know the percentage of the Internet that's valid, do you? Jesus, it's scary." - Hunter S. Thompson Last edited by teksimple : 27th June 2007 at 16:57.
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27th June 2007, 17:18	#18 (permalink)
RonMicjan Cap Ron scourge of the NW Current Rebreather/s: Megalodon Dolphin Home Build Other Rebreather/s: Sport Kiss Classic Kiss Dolphin Home Build Join Date: Feb 2005 Location: Cape Disapointment, The Graveyard of the Pacific Posts: 1,083	Re: Can divers with a PFO, still dive on O2 CCR? Thanks for the note Tek, no wonder I was ignorant of the subject, its a non-issue. Only so much room in my brain, must keep it loaded with relevant stuff, like how to make hollandaise sauce for my eggs bennie "in the unlikely event of an oxygen bend..." wait 15 minutes. __________________ Ron "Life is pain princess, anyone who tells you different, is selling something", The Dread Pirate Wesley. www.tmishop.com Diving bits etc.
(Online)

27th June 2007, 20:14	#19 (permalink)
teksimple Enlightened Alpinist Current Rebreather/s: Sport Kiss MK 15.X Other Rebreather/s: Sport Kiss Classic Kiss Join Date: Apr 2005 Location: Back in Hawaii Posts: 495	Re: Can divers with a PFO, still dive on O2 CCR? Quote: (Originally Posted by RonMicjan) Thanks for the note Tek, I guess no one got my deadpan humor. "Vitally challenged"=deceased=dead. __________________ ---- _____________ "I don't know the percentage of the Internet that's valid, do you? Jesus, it's scary." - Hunter S. Thompson
(Offline)

27th June 2007, 22:36	#20 (permalink)
Diver Dave New Member Current Rebreather/s: Dolphin Home Build Other Rebreather/s: Dolphin Home Build Join Date: Mar 2006 Location: So California Posts: 9	Re: Can divers with a PFO, still dive on O2 CCR? Hey Ron These are the thought from the doc at the UCLA chamber. First, most people with PFO's dive (most don't know they have it and it is very common). It doubles the risk of DCS (but to a still low number). We don't routinely look for it unless someone has an undeserved or severe case of the bends or is repeatedly bent. That said, diving on pure O2 should decrease the risk of getting bent, with or without a PFO. I will check into this to see if anyone has studied it (it's really a good thought). Not anything spectacular but if he comes up with any additional info, I will post it. David __________________ "You F##k up, you die!" A quote from a big Jamacian instructor at my first discover SCUBA experience back in 84. It kept me on the ball then and it still works for me today. Diver Dave of So Calif
(Offline)

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