Oxygen toxicity question

Krazyklaws · Sep 18, 2013

Hi there. Can someone explain the difference between central nervous system toxicity and pulmonary or whole body oxygen loading to me please?

I'm a rec diver, nitrox certified but I don't remember mention of pulmonary or whole body oxygen loading.

I'm reading 'the six skills' and it differentiates between that and CNS toxicity.

Thanks x

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Teller · Sep 18, 2013

Short answer...

CNS O2 TOX equals high exposure to O2 over short time. i.e. Single exposure PPO2 1.6 for over 45 minutes or a single exposure to PPO2 1.4 for over 150 minutes. Its tracked in a percentage and generally recommended to not exceed 80%. Common symptoms are convolsions, visual disturbances, nausea and twitching.

Pulmonary is long exposure to O2 and you would have to do alot of diving to worry about it. It is talked about more in technical diving abd is tracked in OTUs or oxygen toxicity units. Still requires alot of diving to be an issue though. Common symptoms are dry cough and feeling burning or irritated lungs.

If this was not covered in your nitrox class or you dont remember it you should take the course again.

uncfnp · Sep 18, 2013

You can find a discussion of this buried within this current thread

http://www.scubaboard.com/forums/ad...ons/465230-how-conservative-ppo2-limit-2.html

Go to post 36 if you want to skip some of the preliminary discussion

Krazyklaws · Sep 18, 2013

Thanks for the nice simple explanation. The thread was helpful too - I think I have a better understanding.

I did an SSI nitrox course and there is literally one paragraph on pulmonary toxicity because it 'Poses no real risk to recreational divers'.

I'm planning on taking an advanced nitrox course next week, so I'm swotting up in advance.

Thanks again.

Karen x

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uncfnp · Sep 18, 2013

Krazyklaws:
Thanks for the nice simple explanation. The thread was helpful too - I think I have a better understanding.

I did an SSI nitrox course and there is literally one paragraph on pulmonary toxicity because it 'Poses no real risk to recreational divers'.

I'm planning on taking an advanced nitrox course next week, so I'm swotting up in advance.

Thanks again.

Karen x

Sent from my iPhone using Tapatalk.

You probably already know this but "Doppler" from that thread wrote The Six Skills...

boulderjohn · Sep 18, 2013

The reason you don't remember pulmonary oxygen toxicity in your basic nitrox course is because it probably was barely mentioned--if at all.

When I took nitrox back in the day, it was a big deal, and I had to do a lot of problems tracking it. What I learned from those problems was that I would have to do some really exceptional diving to make it an issue.

Today's courses don't make a big deal of it because of that. If you are going to do the kind of diving that will make that come into play, which is incredibly unlikely, you will also probably have taken the more advanced courses that will explain it to you.

Teller · Sep 18, 2013

boulderjohn:
The reason you don't remember pulmonary oxygen toxicity in your basic nitrox course is because it probably was barely mentioned--if at all.

When I took nitrox back in the day, it was a big deal, and I had to do a lot of problems tracking it. What I learned from those problems was that I would have to do some really exceptional diving to make it an issue.

Today's courses don't make a big deal of it because of that. If you are going to do the kind of diving that will make that come into play, which is incredibly unlikely, you will also probably have taken the more advanced courses that will explain it to you.

It is covered pretty well in TDI Nitrox but I agree its not a major concern.

Crass3000 · Sep 19, 2013

Teller:
CNS O2 TOX equals high exposure to O2 over short time. i.e. Single exposure PPO2 1.6 for over 45 minutes or a single exposure to PPO2 1.4 for over 150 minutes. Its tracked in a percentage and generally recommended to not exceed 80%. Common symptoms are convolsions, visual disturbances, nausea and twitching.

I'm surprised nobody has been critical of this. As you know the PPO2 that results in CNS O2 Tox isn't a perfect science. I find it interesting that you somehow find yourself able to quote time limits, etc. The truth is that we really don't know how long you can be exposed at even PPO2 1.4 on any given day although I would feel comfortable diving that level. Any higher than that and you really have no idea how long you have or if you will have symptoms. He did mention some symptoms but in most classes and books they will tell you that you would be unlikely to notice any other symptom besides the convulsions. My understanding is that the other symptoms are typically so short in length that you probably wouldn't notice them. They are more likely symptoms that people have found in a compression tank that they used to test diver's in.

Teller · Sep 19, 2013

Crass3000:
Teller:

CNS O2 TOX equals high exposure to O2 over short time. i.e. Single exposure PPO2 1.6 for over 45 minutes or a single exposure to PPO2 1.4 for over 150 minutes. Its tracked in a percentage and generally recommended to not exceed 80%. Common symptoms are convolsions, visual disturbances, nausea and twitching.

Click to expand...

I'm surprised nobody has been critical of this. As you know the PPO2 that results in CNS O2 Tox isn't a perfect science. I find it interesting that you somehow find yourself able to quote time limits, etc. The truth is that we really don't know how long you can be exposed at even PPO2 1.4 on any given day although I would feel comfortable diving that level. Any higher than that and you really have no idea how long you have or if you will have symptoms. He did mention some symptoms but in most classes and books they will tell you that you would be unlikely to notice any other symptom besides the convulsions. My understanding is that the other symptoms are typically so short in length that you probably wouldn't notice them. They are more likely symptoms that people have found in a compression tank that they used to test diver's in.

No one was critical about it because its straight from what NOAA recommends and seeing how this isnt a Nitrox class I didnt feel the need to go in depth about symptoms.

Crass3000 · Sep 19, 2013

Teller:
No one was critical about it because its straight from what NOAA recommends and seeing how this isnt a Nitrox class I didnt feel the need to go in depth about symptoms.

For some reason I figured you must have taken it out of a book but it seems quite strange that they would make such quotes when people assuredly have got CNS O2 Tox from lesser exposure.

Oxygen toxicity question

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Krazyklaws

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