O2 toxicity in deco chamber

[Boogie711]

Does the flopping around drive the nitrogen bubbles out of your system faster??

I've heard that it does - it crushes them much smaller.

Which is why from now on I'm not going to worry about ascent rates or deco limits - I'm just going to go head down and inflate my drysuit. I'll ascend feet first, making all the bubbles go into my feet.

Then when I get on the boat, I'll just dance and stomp around for a bit, smashing all the bubbles. This is safer and easier than worrying about NDL's, right?

 

[RichLockyer]

Add to that the medical supervision, the fact that O2 Tox is quickly and easily identified before it gets too dangerous, and the ability to flush the chamber to reduce the O2 PP - Yes it is safe.

Keep in mind that most chambers, IIRC, ALL multiplace chambers, which would include those housing an attendant medic, are pressurized with air while the patient gets his O2 from a mask to reduce the risk of fire.

And yes, narcosis is a factor and the attending medic in the chamber does NOT make decisions... he follows the direction of a doctor outside.

 

[Sirto]

Keep in mind that most chambers, IIRC, ALL multiplace chambers, which would include those housing an attendant medic, are pressurized with air while the patient gets his O2 from a mask to reduce the risk of fire.

And yes, narcosis is a factor and the attending medic in the chamber does NOT make decisions... he follows the direction of a doctor outside.

It was just as you stated, a chamber pressurized with air while O2 was supplied via a mask. Their was noone inside with her though there was an adjacent section in the chamber where someone could get pressurized and then enter the section that my wife was in.

Breathing air would have been easy , just remove the mask. However, this was not done.

 

[Sirto]

It is, as Jeff is trying to determine, unlikely that the air "breaks" were actually skipped. Hence his questions about the exact treatment table and type of chamber.

BJD

DMT :doctor:

The only way she could have breathed air was to
a) remove the mask she was breathing from or
b) switch the source of gas going to the mask

I was standing their during the entire procedure and did not see either of these done.

 

[Dr Deco]

Hello Sirto:

Breaks

The danger of oxygen toxicity is greatly reduced when the person is at rest. Carbon dioxide plays a role in the etiology (cause) of CNS toxicity. It is a vasodilator in the brain and this might be the reason. While air breaks are desirable, they are not an absolute necessity in most cases.

Bubbles

Actually thrashing around will not rid the body of nitrogen faster. In fact, considerable experimental evidence suggests that physical activity while you are supersaturated leads to bubble formation and growth.

Dr Deco :doctor:

 

[Boogie711]

Bubbles

Actually thrashing around will not rid the body of nitrogen faster. In fact, considerable experimental evidence suggests that physical activity while you are supersaturated leads to bubble formation and growth.

Dr Deco :doctor:

WHOA - what are you saying? That my "ascend feet first and then dance" routine won't actually work! :11:

Darnit - I thought I was on to something there...

 

[DiveExtreme22]

WHOA - what are you saying? That my "ascend feet first and then dance" routine won't actually work! :11:

Darnit - I thought I was on to something there...

probably not...itd be pretty amusing to watch though

 

[SoCalAngel]

I've been doing some reading about O2 toxicity and am have a question about a recent chamber ride my wife took.

After the fact I've found that it was a Table 5 (almost) profile, 60 ft then 30 ft on pure oxygen. I say almost because I've learned that table 5 profile calls for 3 5 minute breaks breathing air.

This was not done in the case of my wife.

I just did a couple of chamber rides last month. During the first treatment, in the middle of my first air break, the fog lifted and I asked about O2. Suddenly, the light went on I asked about my partial pressure and fraked out. They put the hood on and my mind went to work doing the amth. I figured I was at a 2.6 or 2.8 pp of O2. When I had my second break I took the hood off, and asked to talk with the Dr.

What I was told, was that the risk of a CNS hit while at rest, under the care of a medical technician, was very low. When you are in the water, you are working which is what increases the risk of CNS.

Also, I was told that a safe pp is actually closer to 2.0 while in the water. Dr. Deco, is this accurate?
:06:

 

[Spectre]

Also, I was told that a safe pp is actually closer to 2.0 while in the water. Dr. Deco, is this accurate?

Depends on what you define as 'safe'.

 

[pdoege]

The treatment tables call for very high pp02 in order to get the N2 out of the body.

In my opinion, the doctors,whatever are not concerned about 02 tox because they can always switch to air if it occurs.

In the water if you tox you pretty much die from drowning. That is not an issue in the chamber.

The air breaks are there to help prevent pulmonary damage.

As for the claim that the doctors/attendants/whoever didn't do air breaks. Who knows? Depending on the chamber design the switch over to air may not be obvious to the untrained; maybe they never switched.

Did the patient recover? That is the bottom line.

Peter

PS. The oxygen toxicity "safeness" is based on statistical analysis. You can get a toxicity hit at "low" pp02s like 1.3. It all depends on the situation.