Treating suspected DCI with 100% O2 (is it wrong?)

***ScubaDadMiami*** · 1st February 2006, 03:49

When treating DCI, you want to treat with the highest amount of oxygen that the body can tolerate given toxicity constraints.

abowie · 1st February 2006, 05:05

Quote: (Originally Posted by Deepthought)

Apart from the inability to spell (Presume he means Helium and veins contract) his opinion seems very wrong.

Andy

Yes, correct on both counts; he can't spell and he is very wrong.

divetheworld · 1st February 2006, 07:05

Quote: (Originally Posted by Genesis)

What the others have said.

On the surface, first aid for DCI is 100% O2. Why? Because there's no inert gas in there, which maximizes the gradient. That's the point - until you can get the victim to a chamber where they can add crushing the bubbles to maximizing the gradient.

There ARE some instances where pure O2 is dangerous (in someone with an impaired CO2 breathing reflex) but those folks are EXTREMELY unlikely to be diving in the first place - that usually shows up with someone who has severe emphysema and their body has developed an adaptive response where arterial PO2 mediates the breathing reflex instead of blood CO2 content. Those folks have such severe compromise of their pulmonary function in the first place that they are are unlikely to be able to exert themselves at a level necessary to pass even a PADI swim test.....

Thats a perfect elaboration on what I was saying, well articulated.

In addition, there are some inherrant dangers of administering other than 100% pure O2.
The use of a helium mix can actually cause big problems when treating DCi. Mr Radomski, step in here any time. I remember reading a very well put post that I have quoted below. Food for thought even if the context was the use submerged.

Quote: (Originally Posted by jradomski)

It is definately NOT a good practice to go from a mix with little or no He to a mix with More helium in it.. Since He is such a fast gas a point of supersaturation can occur on a saturated compartment, creating a bend underwater.. For safety bailing in this manner would require DESCENDING for a period to allow the slower N2 to give some "room" to the faster He which now has a high gradient to get into the tissues..

A Heavy to Light gas switch is a bad idea once tissues are loaded, a light to heavy gas switch is ok..

Wise words.

Gasman · 3rd February 2006, 08:53

As David said, the first aid for DCI is 100% O2…period.

The recent publication of the DAN workshop on DCI in remote locations has raised the idea of In Water Recompression (IWR) again and may be something that some suitably trained and equipped groups may consider. Certainly, omitted decompression with a surface interval of less than 5 minutes can be treated with suitable omitted deco tables.

Helium based treatment tables, notably the COMEX 30 and COMEX 50 (and RN Helium tables) are largely based on the work of Hyldegaard[1, 2] from the 1990's. Recent work [3] has confirmed that the idea of Helium as a "fast" gas is probably flawed and would help explain these results from 10 years earlier. We have found these table to be very effective for severe cases of DCI i.e Spinal etc DCI. We use these gases because the depth of the table is deeper than the maximum acceptble O2 depth for in chamber dives (i.e.3 ATA). Therefore we would have to use either a nitrox mix or Heliox and the litereature supports the Heliox option. Nevertheless, it is ill advised to attempt to use Helium based gases for IWR as there is no data to support this practice and it is unlikely that suitable equipment would be available. Additionally the concept of IWR in the open ocean is generally considered a recipe for disaster. Surface based He gases offer NO advatage over 100% O2. Given that the majority of divers have never attempted to deal with this sort of problem, the safest approach is to get the diver into the boat, administer 100% O2 and call for help.

Remember:

Air goes IN and OUT
Blood goes Round and Round
And
Oxygen is GOOD!

Call for help early!

1. Hyldegaard, O. and J. Madsen, Effect of air, heliox, and oxygen breathing on air bubbles in aqueous tissues in the rat. Undersea Hyperb Med, 1994. 21(4): p. 413-24.
2. Hyldegaard, O., M. Moller, and J. Madsen, Effect of He-O2, O2, and N2O-O2 breathing on injected bubbles in spinal white matter. Undersea Biomed Res, 1991. 18(5-6): p. 361-71.
3. Doolette, D.J., R.N. Upton, and C. Grant, Perfusion-diffusion compartmental models describe cerebral helium kinetics at high and low cerebral blood flows in sheep. J Physiol, 2005. 563(Pt 2): p. 529-39.

Andrew

NeilHolden · 3rd March 2006, 18:19

Hi,

just to add my 2p worth.

There are other clinical advantages to using 100% O2 (normally only obvious when using hyperbaric therapy). However any advantage is good.

For all first aid 100% O2 should be administered (or the highest pct that is available). For info if a demand valve is used (not an oral nasal mask) then a nose clip should also be used to prevent any dilution through inadvertant breathing through the nose! I understand that a minimum flow rate of 15 lpm is required to achieve 98% unless dumped directly (demand valve) - any sort of bag or resuscitation device has dead space etc. Administration of any mix with inert gas reduces the effect and benefit.

Additional info:

Treatment under hyperbaric conditions (including the He tables mentioned in another post) are all conducted on a case by case (ie profile / symptoms) basis, usually in consultation with a diving medical specialist (doctor).

Most 'normal' therapies involve O2 at 18m (time varies), very occasionally requiring deeper
therapy to 50m (start on air, transfer to O2 at 18m). But this is going off thread by a mile

!

Summary: 100% O2 is good first aid for a diver with suspected DCI (and other ailments!)

denzel · 4th March 2006, 14:06

Awhile ago I read/heard that it might be a wise idea to not administer the O2 too soon, because it would make it more difficult/ impossible to see if really any symptoms would come up.
IE when a diver comes up after having missed one or more stops, wait till symptoms appear before giving O2.

Does this make sense or should I stay out of the "coffeeshops"?

denz.

Genesis · 4th March 2006, 14:16

If no symptoms come up, then there's no problem, right? With DCS the symptoms are the disease!

This sort of nonsense has been floating around out there for quite a while, and its dangerous. If you have ANY reason to believe you blew a profile, suck some (pure) O2. It may or may not prevent a hit, but if it doesn't, it very well may lessen the severity of it.

It sure won't hurt you - getting the inert gas out of your body in whatever amount you can accomplish it is NOT bad.

Nick uk. · 4th March 2006, 16:41

Polmo aveolo constriction occurs when breathing O2 at high PpO2 levels....It's why we do 'air breaks', on the surface breathing O2 can have no side effects, if in doubt, get it out!!

apitkin · 5th March 2006, 00:45

Quote: (Originally Posted by Nick uk.)

Polmo aveolo constriction occurs when breathing O2 at high PpO2 levels....It's why we do 'air breaks', on the surface breathing O2 can have no side effects, if in doubt, get it out!!

I assume you mean 'pulmonary alveolar constriction'? Sorry mate, but there's no such thing. There is a thing called hypoxic pulmonary vasoconstriction, but it's the blood vessels (pulmonary capillaries) that constrict, not the alveoli. And the capillaries constrict in response to low levels of oxygen, not high levels.

And (also) no, it's not why we do 'air breaks'. we do air breaks to reduce the risk of CNS oxygen toxicity.

However, you're definitely correct with 'if in doubt, get it out!!'

Andy

PS Sorry to be a pedant, but generally the info on this board is so good, I'd like to keep it that way.

Nick uk. · 5th March 2006, 06:44

was under the impression that extended exposures to high levels of O2 restricted the capilleries at a polmonary level compromising the gas exchange, and is why do air breaks, to represtinate their efficiency....

Alveoare, capiilare....

got them wrong way round

sorry....

1st February 2006, 03:49	#11 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 2,073	Re: Treating suspected DCI with 100% O2 (is it wrong?) When treating DCI, you want to treat with the highest amount of oxygen that the body can tolerate given toxicity constraints. __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com Last edited by ScubaDadMiami : 1st February 2006 at 03:52.
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1st February 2006, 05:05	#12 (permalink)
abowie Fighting Girl Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: May 2005 Location: Land of Oz Posts: 573	Re: Treating suspected DCI with 100% O2 (is it wrong?) Quote: (Originally Posted by Deepthought) Apart from the inability to spell (Presume he means Helium and veins contract) his opinion seems very wrong. Andy Yes, correct on both counts; he can't spell and he is very wrong. __________________ Andrew Bowie Rebreather-friendly Buddy
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1st February 2006, 07:05	#13 (permalink)
divetheworld Dive porn pimp Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Classic Kiss Other CCR Join Date: Mar 2005 Location: Leeds, England Posts: 1,562	Re: Treating suspected DCI with 100% O2 (is it wrong?) Quote: (Originally Posted by Genesis) What the others have said. On the surface, first aid for DCI is 100% O2. Why? Because there's no inert gas in there, which maximizes the gradient. That's the point - until you can get the victim to a chamber where they can add crushing the bubbles to maximizing the gradient. There ARE some instances where pure O2 is dangerous (in someone with an impaired CO2 breathing reflex) but those folks are EXTREMELY unlikely to be diving in the first place - that usually shows up with someone who has severe emphysema and their body has developed an adaptive response where arterial PO2 mediates the breathing reflex instead of blood CO2 content. Those folks have such severe compromise of their pulmonary function in the first place that they are are unlikely to be able to exert themselves at a level necessary to pass even a PADI swim test..... Thats a perfect elaboration on what I was saying, well articulated. In addition, there are some inherrant dangers of administering other than 100% pure O2. The use of a helium mix can actually cause big problems when treating DCi. Mr Radomski, step in here any time. I remember reading a very well put post that I have quoted below. Food for thought even if the context was the use submerged. Quote: (Originally Posted by jradomski) It is definately NOT a good practice to go from a mix with little or no He to a mix with More helium in it.. Since He is such a fast gas a point of supersaturation can occur on a saturated compartment, creating a bend underwater.. For safety bailing in this manner would require DESCENDING for a period to allow the slower N2 to give some "room" to the faster He which now has a high gradient to get into the tissues.. A Heavy to Light gas switch is a bad idea once tissues are loaded, a light to heavy gas switch is ok.. Wise words. __________________ Attitude and self praise is no reccomendation. Dont try to be a great man, just be a man and let history be the judge of you. CHECK OUT OUR INTERWEBS FOR CUSTOM REBREATHER UPGRADES *WWW.NARKEDAT90.CO.UK* *http://www.grpservices.com/pursuit/* Supporting Shearwater Research Products in Europe
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3rd February 2006, 08:53	#14 (permalink)
Gasman New Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Australia Posts: 33	Re: Treating suspected DCI with 100% O2 (is it wrong?) As David said, the first aid for DCI is 100% O2…period. The recent publication of the DAN workshop on DCI in remote locations has raised the idea of In Water Recompression (IWR) again and may be something that some suitably trained and equipped groups may consider. Certainly, omitted decompression with a surface interval of less than 5 minutes can be treated with suitable omitted deco tables. Helium based treatment tables, notably the COMEX 30 and COMEX 50 (and RN Helium tables) are largely based on the work of Hyldegaard[1, 2] from the 1990's. Recent work [3] has confirmed that the idea of Helium as a "fast" gas is probably flawed and would help explain these results from 10 years earlier. We have found these table to be very effective for severe cases of DCI i.e Spinal etc DCI. We use these gases because the depth of the table is deeper than the maximum acceptble O2 depth for in chamber dives (i.e.3 ATA). Therefore we would have to use either a nitrox mix or Heliox and the litereature supports the Heliox option. Nevertheless, it is ill advised to attempt to use Helium based gases for IWR as there is no data to support this practice and it is unlikely that suitable equipment would be available. Additionally the concept of IWR in the open ocean is generally considered a recipe for disaster. Surface based He gases offer NO advatage over 100% O2. Given that the majority of divers have never attempted to deal with this sort of problem, the safest approach is to get the diver into the boat, administer 100% O2 and call for help. Remember: Air goes IN and OUT Blood goes Round and Round And Oxygen is GOOD! Call for help early! 1. Hyldegaard, O. and J. Madsen, Effect of air, heliox, and oxygen breathing on air bubbles in aqueous tissues in the rat. Undersea Hyperb Med, 1994. 21(4): p. 413-24. 2. Hyldegaard, O., M. Moller, and J. Madsen, Effect of He-O2, O2, and N2O-O2 breathing on injected bubbles in spinal white matter. Undersea Biomed Res, 1991. 18(5-6): p. 361-71. 3. Doolette, D.J., R.N. Upton, and C. Grant, Perfusion-diffusion compartmental models describe cerebral helium kinetics at high and low cerebral blood flows in sheep. J Physiol, 2005. 563(Pt 2): p. 529-39. Andrew
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3rd March 2006, 18:19	#15 (permalink)
NeilHolden Gadget Freak Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic MK 15.X Join Date: Feb 2006 Location: Fareham, Hampshire Posts: 67	Re: Treating suspected DCI with 100% O2 (is it wrong?) Hi, just to add my 2p worth. There are other clinical advantages to using 100% O2 (normally only obvious when using hyperbaric therapy). However any advantage is good. For all first aid 100% O2 should be administered (or the highest pct that is available). For info if a demand valve is used (not an oral nasal mask) then a nose clip should also be used to prevent any dilution through inadvertant breathing through the nose! I understand that a minimum flow rate of 15 lpm is required to achieve 98% unless dumped directly (demand valve) - any sort of bag or resuscitation device has dead space etc. Administration of any mix with inert gas reduces the effect and benefit. Additional info: Treatment under hyperbaric conditions (including the He tables mentioned in another post) are all conducted on a case by case (ie profile / symptoms) basis, usually in consultation with a diving medical specialist (doctor). Most 'normal' therapies involve O2 at 18m (time varies), very occasionally requiring deeper therapy to 50m (start on air, transfer to O2 at 18m). But this is going off thread by a mile ! Summary: 100% O2 is good first aid for a diver with suspected DCI (and other ailments!) __________________ Diversi Veshi Tem
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4th March 2006, 14:06	#16 (permalink)
denzel Holiday diver Current Rebreather/s: Inspiration Classic Other Rebreather/s: Not Bought Yet Join Date: Aug 2005 Location: Perth! Posts: 358	Re: Treating suspected DCI with 100% O2 (is it wrong?) Awhile ago I read/heard that it might be a wise idea to not administer the O2 too soon, because it would make it more difficult/ impossible to see if really any symptoms would come up. IE when a diver comes up after having missed one or more stops, wait till symptoms appear before giving O2. Does this make sense or should I stay out of the "coffeeshops"? denz. __________________ My deepest so far, 558.50 mtr, my rig a LF90D...
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4th March 2006, 14:16	#17 (permalink)
Genesis Bubbless Box of Death Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Oct 2005 Location: Sunny Florida Posts: 1,394	Re: Treating suspected DCI with 100% O2 (is it wrong?) If no symptoms come up, then there's no problem, right? With DCS the symptoms are the disease! This sort of nonsense has been floating around out there for quite a while, and its dangerous. If you have ANY reason to believe you blew a profile, suck some (pure) O2. It may or may not prevent a hit, but if it doesn't, it very well may lessen the severity of it. It sure won't hurt you - getting the inert gas out of your body in whatever amount you can accomplish it is NOT bad. __________________ "A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American." http://www.denninger.net http://www.diversunion.org/liability.htm - Fix the Diving Cert racket
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4th March 2006, 16:41	#18 (permalink)
Nick uk. Made in England. Current Rebreather/s: Inspiration Classic Azimuth Other Rebreather/s: Azimuth Join Date: Nov 2005 Location: Viale C.Colombo 75 Marina di Carrara. MS 54036 Italy Posts: 579	Re: Treating suspected DCI with 100% O2 (is it wrong?) Polmo aveolo constriction occurs when breathing O2 at high PpO2 levels....It's why we do 'air breaks', on the surface breathing O2 can have no side effects, if in doubt, get it out!! __________________ If it aint broke....don't fix it, and if it is.............well......get another one! divechief2000@hotmail.com
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5th March 2006, 00:45	#19 (permalink)
apitkin New Member Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Feb 2005 Location: Cloud Cuckoo Land Posts: 100	Re: Treating suspected DCI with 100% O2 (is it wrong?) Quote: (Originally Posted by Nick uk.) Polmo aveolo constriction occurs when breathing O2 at high PpO2 levels....It's why we do 'air breaks', on the surface breathing O2 can have no side effects, if in doubt, get it out!! I assume you mean 'pulmonary alveolar constriction'? Sorry mate, but there's no such thing. There is a thing called hypoxic pulmonary vasoconstriction, but it's the blood vessels (pulmonary capillaries) that constrict, not the alveoli. And the capillaries constrict in response to low levels of oxygen, not high levels. And (also) no, it's not why we do 'air breaks'. we do air breaks to reduce the risk of CNS oxygen toxicity. However, you're definitely correct with 'if in doubt, get it out!!' Andy PS Sorry to be a pedant, but generally the info on this board is so good, I'd like to keep it that way.
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5th March 2006, 06:44	#20 (permalink)
Nick uk. Made in England. Current Rebreather/s: Inspiration Classic Azimuth Other Rebreather/s: Azimuth Join Date: Nov 2005 Location: Viale C.Colombo 75 Marina di Carrara. MS 54036 Italy Posts: 579	Re: Treating suspected DCI with 100% O2 (is it wrong?) was under the impression that extended exposures to high levels of O2 restricted the capilleries at a polmonary level compromising the gas exchange, and is why do air breaks, to represtinate their efficiency.... Alveoare, capiilare.... got them wrong way round sorry.... __________________ If it aint broke....don't fix it, and if it is.............well......get another one! divechief2000@hotmail.com
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