O2 toxicity in deco chamber

[Sirto]

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 am not a nitrox diver and knew that O2 toxicity existed but did not know, at the time, what the limits were but I specificaly asked the Dr at the hyperbaric chamber about why 100% O2 at 60 feet wasn't toxic. He gave an explaination that I didn't fully understand.

Now that I've read up on it some more I wonder if the treatment was dangerous.

Please give me your thoughts.

Ed

 

[Boogie711]

There's a really simplistic way of looking at this:

What happens when you tox underwater? You can drown.

What happens when you tox in a chamber? You flop around for a few minutes under trained medical supervision.

I'll take the risk of toxing in a chamber if it means they can drive any nitrogen bubbles out of my system and decompress me safely, thanks very much.

 

[Ontario Diver]

As well, there are a host of other factors. One of the key ones is that O2 tox limits are highly influenced by environmental and physical conditions. In the case of a chamber ride, the patient is at rest, warm, and (hopefully) reasonably comfortable. This significanly lessens the chance of an 02 tox hit. Remember, being safe recreational nitrox divers use a O2PP maximum of 1.6. US Navy divers routinely use 2. 100% O2 at 30 ft gives a O2 PP of 2.

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.

 

[rmediver2002]

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 am not a nitrox diver and knew that O2 toxicity existed but did not know, at the time, what the limits were but I specificaly asked the Dr at the hyperbaric chamber about why 100% O2 at 60 feet wasn't toxic. He gave an explaination that I didn't fully understand.

Now that I've read up on it some more I wonder if the treatment was dangerous.

Please give me your thoughts.

Ed

Could it have been a TT-9 / Kendall table? (treatment depth is 45 FSW) the O2 breathing periods are longer.

 

[Sirto]

Could it have been a TT-9 / Kendall table? (treatment depth is 45 FSW) the O2 breathing periods are longer.

It was somewhere around 2.5 hours and was definetely at 60 ft / 30ft

 

[Sirto]

As well, there are a host of other factors. One of the key ones is that O2 tox limits are highly influenced by environmental and physical conditions. In the case of a chamber ride, the patient is at rest, warm, and (hopefully) reasonably comfortable. This significanly lessens the chance of an 02 tox hit. Remember, being safe recreational nitrox divers use a O2PP maximum of 1.6. US Navy divers routinely use 2. 100% O2 at 30 ft gives a O2 PP of 2.

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.

So, to confirm, you don't feel that it was a problem in skipping the breathing of air occasionally during this treatment?

 

[rmediver2002]

Was it a monoplace chamber (single compartment for the patient, normally made from acrylic) or were you in the chamber with a tender breathing from either a hood or bibbs mask?

Monoplace chambers usually are set up to vent the O2 and supply only air for the required air brakes, when breathing from bibbs mask or a hood the item is normally removed for the break.

It would not be keeping with any established protocol to do a treatment table that did not follow the air breaks. They are required on US Navy TT-5 if that is what was being followed.

 

[BigJetDriver]

So, to confirm, you don't feel that it was a problem in skipping the breathing of air occasionally during this treatment?

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:

 

[DEEPLOU]

There's a really simplistic way of looking at this:

What happens when you tox underwater? You can drown.

What happens when you tox in a chamber? You flop around for a few minutes under trained medical supervision.

I'll take the risk of toxing in a chamber if it means they can drive any nitrogen bubbles out of my system and decompress me safely, thanks very much.

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

 

[pt40fathoms]

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

No.

But it sure wakes up the operator and makes the boring day go by just that much faster. I would be worried if several operators stood around watching, and ended up passing money to one at the start of the "flopping around". :11: