How does oxygen treat DCS/AGE?

[wetvet]

I know this seems like a fairly basic question, but an instructor and I were having a discussion on how O2 treatment on a boat (ie non-hyperbaric) affects someone suffering from DCS or AGE. I was under the impression that by giving no nitrogen in the breathing gas, you increased the diffusion gradient in the blood so that a nitrogen bubble(s) would dissolve back into solution. He believes that giving 100% O2 only decreases or prevents the formation of new bubbles, and does nothing to reduce bubbles already in the system, and that the only way to remove bubbles from tissues is to recompress the patient.


The basis for the discussion was this-- I suffered an AGE a couple months back, and there was no O2 available on the private boat I was on. I believe I was fortunate that there was no O2 there, since I recovered completely before the option for treatment was available. If I had O2 on the boat, and then recovered, I would have believed I had a Type II DCS hit, and my prospects for diving again would be very low. As it is, I feel that if I can identify the cause of the bubble that travelled to my brain, and fix the cause, I can dive confidently again.

To make a long question short.....does O2 treatment dissolve bubbles in tissues?

....does the fact that my neurological symptoms resolved spontaneously (without O2 or hyperbaric treatment) make it more likely that I had an AGE vs TypeII DCS?

Thanks for any input.

Wetvet

 

[Dive-aholic]

I believe the effects of 100% O2 depend on whether you are breathing it at atmospheric pressure or at hyperbaric pressures. At atmospheric pressure, you are right. At hyperbaric pressure, your instructor is right. I haven't looked into it that much, but this would be my guess on how it works.

What makes you think you suffered an AGE? If it resolved spontaneously, I'd think that it may not have been DCS at all, and to look for some other cause for the symptoms.

 

[divenutny]

wetvet - I recommend you send this question past DAN. I'm sure they can provide a better response to the phyisiological effect of breathing 100% O2 or high concentrations of O2 (50% or higher). There is a lot of theory I am not explaining.

As I understand it, breathing high concentrations of O2 help your lungs release nitrogen that is in solution. Once bubbles are formed past a certain size, your body should not be able to reduce them or dissolve them unless your body is re-pressurized, squeezing the bubbles back to a size they can be put back in solution. Breathing 100% O2 will not reduce the bubbles, only possibly reduce the chances of getting more bubbles. Note that your blood stream can handle small bubbles. Once the bubble volume gets to high, the bubbles can combine getting to large to handle causing AGE. AGE is rather serious as it can block your blood flow.

From the little knowledge I have acquired, I would look to other issues than AGE for your symptoms. AGE means bubbles formed in you blood, not your tissues. I would expect someone with AGE would also have serious type II issues.

Should you contact DAN, give them your dive profile(s) including ascent rates. They should be able to better explain this.

Hope this helps - Tom

 

[Gene_Hobbs]

I would suggest starting out by reading:

First aid normobaric oxygen for the treatment of recreational diving injuries.
Longphre, DeNoble, Vann, Moon, and Freiberger. Undersea Hyperb Med. 2007 Jan-Feb;34(1):43-9.
PubMed ID: 17393938

As per our agreement with the UHMS, we can not add this paper to the Rubicon Repository until January (sorry).

Here is the 2005 UHMS abstract on the topic though:
UTILITY OF FIRST AID OXYGEN PRIOR TO RECOMPRESSION TREATMENT FOR DIVING INJURIES.
Longphre, Freiberger, DeNoble, and Vann. UHMS abstract 2005.
RRR ID: 1766

The work was published as an article in the Alert Diver and the UHMS Diving Committee is doing a nice write up on this work that should be done soon.

If you are really interested in how HBO treatment for these conditions started, Bob's paper is a good start with the early work:

EXPERIENCE WITH MINIMAL RECOMPRESSION, OXYGEN BREATHING TREATMENT OF DECOMPRESSION SICKNESS AND AIR EMBOLISM.
Bornmann. 1967 NEDU report
RRR ID: 3344

 

[Kevrumbo]

Goals of Oxygen Therapy in suspected DCS Syndrome case:
-Bubble Resolution through Denitrogenation (bubble contents almost pure nitrogen).
-Surround bubble with high oxygen environment
-Diffuse Nitrogen out of bubble into blood.
-Nitrogen transported to the lungs and exhaled.

Augmented with Hyperbaric Oxygen Therapy (HBO), goals are:
-Bubble size reduction (vital in suspected case of AGE).
-Hyperbaric oxygenation of hypoxic tissues.
-Reduction of tissue edema.
-Rehydration (e.g. Oral hydrating fluids or IV Normal Saline during Treatment).

Bubble size Reduction:
Decompression Sickness, small bubbles:
-Treatment starts at 60fsw (2.8 Ata) on 100% Oxygen, with theoretical 70% reduction of Original Bubble Diameter.

Arterial Embolism, large gas bubbles:
-Treatment starts at 165fsw (6.0 Ata) on 47% Oxygen, with 55% of Original Bubble Diameter.

 

[Zippsy]

Breathing pure O2 helps by getting more O2 to your tissues and organs which they desperately need. It also helps to eliminate nitrogen in solution from your system. It does not, however, that is somehow going to reduce bubble sizes. The only thing that does that is re-compression. You can not spontaneously recover from AGE and DCS type II without treatment.

 

[jefffalcone]

Correct me if I'm wrong, but isn't AGE the most severe form of DCS?

 

[Zippsy]

No, I believe it's the most severe form of lung over-expansion injury, which along with the other lung over-expansion injuries come under the general term "decompression injury" or "decompression illness". Decompression sickness just refers to what is commonly called "the bends".

 

[Henryville]

No, I believe it's the most severe form of lung over-expansion injury, which along with the other lung over-expansion injuries come under the general term "decompression injury" or "decompression illness". Decompression sickness just refers to what is commonly called "the bends".

There are ways to get an AGE other than a lung over-expansion injury, which is probably why the OP made the comment that he did about identifying the source and potentially diving again.

 

[divenutny]

Correct me if I'm wrong, but isn't AGE the most severe form of DCS?

The difference between DCS and AGE is where the bubble forms. For DCS, the bubble forms in the a tissue (muscle, organ). For AGE, the bubble forms in your blood stream. The reason AGE is more serious is bubble in your blood stream can stop the blood flow to a specific area of the body causing other issues. Over expansion of the lungs is a different issue. Some of the aviolii have ruptured, causing bleeding or rupturing/collapsing the lung. How do stay off your lungs until they heal? Although the body many have had high nitrogen levels when the lung was over expanded, the high nitrogen level did not cause the over expansion, it was trauma from not allowing the gas to leave the lungs.

Hope this helps - Tom