YD Scuba Diving Forums banner

1 - 20 of 34 Posts

·
aka Chimp 1 or Mavis...
Joined
·
10,108 Posts
Discussion Starter · #1 ·

·
Mr potty mouth: Sweeping generalist...............
Joined
·
2,382 Posts
83% of woman surveyed* claimed they felt more in touch with their inner self after their other half buys them flowers kinda research again I see?

* sample size of 6 woman of which one decided she was a man right before she was surveyed, results may vary depending on mood

I see assumptions and generalisations wrapped as marketing spin again, if you were not 'other inclined' I could accuse you of cross posting spam. :p

Note to self, gota get me one of those PDF maker programs to up my credibility some too....

Peter
 
  • Like
Reactions: gobfish1

·
more weaselly than a weaselly thing
Joined
·
3,628 Posts
As i posted elsewhere, lots of nice opinions, not much science/evidence.
 

·
Still young enough to know everything
Joined
·
4,001 Posts
Hummm... I'd have gone for "scaremongering twaddle".
As for the PPO2 levels, I have no idea, it may be, I was refering to the way in which air breaks reduce the chance of O2 toxicity being educating :)
 

·
loop14
Joined
·
690 Posts
Mmm it does seem a bit flakey, would these fatalities, "(many almost certainly as a result of O2 toxicity)", have been avoided by diving a setpoint of 1.2?
 

·
give me convenience
Joined
·
2,436 Posts
Sounds like a long winded way to recommend air breaks to me. I do not see why they would be difficult in practice on a CCR.

Best

Kev
 

·
Mr potty mouth: Sweeping generalist...............
Joined
·
2,382 Posts
Sounds like a long winded way to recommend air breaks to me. I do not see why they would be difficult in practice on a CCR.

Best

Kev
T's called a loop flush my friend and it's also a nifty way of validating your cells to DIL PPO2.
We breather divers are not all tricks and gadgets you know.... :D
 
  • Like
Reactions: gobfish1

·
Nigel Hewitt
Joined
·
7,142 Posts
Sounds like a long winded way to recommend air breaks to me. I do not see why they would be difficult in practice on a CCR.
Who carries air on a rebreather?

I'm pessimistic about air breaks. Without a proper theory as to how they work or a statistical double blind test I'm unconvinced. It's another 'Nitrox makes me less tired' story.
 

·
Registered
Joined
·
25 Posts
PHP:
Who carries air on a rebreather?

I'm pessimistic about air breaks. Without a proper theory as to how they work or a statistical double blind test I'm unconvinced. It's another 'Nitrox makes me less tired' story.
Air breaks don't have to be done on "air", just low o2 content

You should talk to the very nice people that man the chambers around the country. They seem to think Air Breaks are an important part of the recompression therapy they carry out on us divers

Is the "nitrox makes me less tied" comment because it contains more o2 or less nitrogen

Re the article in question, for me it doesn't say anything new, and presumes to explain away reasons for fatalities, without actual evidence

paul
 

·
Jesus don't want me for a sunbeam
Joined
·
13,407 Posts
I'm always suspicious whenever I see mysterious unexplained deaths suddenly explained by a thought experiment by someone with no access to any evidence other than what they've read on the internet. I'd half expected an occasional rebreather manufacturer to be cited as a reference :rolleyes:

I've always thought low setpoints were a good idea but I don't think the article makes a particularly good case for it.
 

·
Mr potty mouth: Sweeping generalist...............
Joined
·
2,382 Posts
It does finish with a flourish for EAC's solving all of the world's ills but forgets to mention you won't get the run time from them that you expect and that high PPO2 masks Hypercapnia until critical....
Perhaps that's the key learning for those on EAC driven units in all of this spin, drop your PPO2 lest you not notice how far down the rabbit hole you are?
 

·
The worlds slowest sailor.
Joined
·
2,970 Posts
PHP:
Air breaks don't have to be done on "air", just low o2 content

You should talk to the very nice people that man the chambers around the country. They seem to think Air Breaks are an important part of the recompression therapy they carry out on us divers

Is the "nitrox makes me less tied" comment because it contains more o2 or less nitrogen

Re the article in question, for me it doesn't say anything new, and presumes to explain away reasons for fatalities, without actual evidence

paul
they use air breaks cos of the very high levels of ppo2 on some of the treatments.
 

·
Nigel Hewitt
Joined
·
7,142 Posts
they use air breaks cos of the very high levels of ppo2 on some of the treatments.
I thought they used air breaks when you started to twitch because managing a convulsion slowed the treatment down.
Remember we are talking chamber levels of say 2.4bar ppO2 - compare like with like.
 

·
currently offshore, please leave a message
Joined
·
1,106 Posts
Nigel,

They use air brakes as standard throughout the treatment - Table 6 being the most common example of this. This happens wether you start to twitch or not.

I know from experience that if you start to twitch, get lung pain etc then they take you off the o2 for even longer than an air break and only put you back on if they feel you can hack it.

G
 

·
Registered
Joined
·
1,770 Posts
Even as a relatively inexperienced CCR diver I can pick several holes in his hypothesis' but still if we all use EAC's we'll be OK:zip:
If you subscribe to this type of marginally thought out "twaddle" (good choice of words Nigel) then why not say, don't dive above 0.7 set point, even less chance of an O2 hit :rolleyes:
 

·
aka Chimp 1 or Mavis...
Joined
·
10,108 Posts
Discussion Starter · #19 ·
Apologies for the sales pitch bit about EACs, I missed that! I was just asking for comment/debate about the various ppO2 setpoints!

Regards
 

·
Jesus don't want me for a sunbeam
Joined
·
13,407 Posts
I thought they used air breaks when you started to twitch because managing a convulsion slowed the treatment down.
Remember we are talking chamber levels of say 2.4bar ppO2 - compare like with like.
During my treatment air breaks were a matter of course. If I remember right then the initial soak is 45min on 2.8bar PO2 with 15min off and then cycled throughout the rest of the treatment. As someone else says, any contraindications to O2 and it's a delay in the treatment, they don't want you hitting the twitchy stage. I would also imagine it isn't particularly easy to manage a convulsing patient in a confined tin can with lots of trailing leads and hoses and crap for the tender on his own.

If you subscribe to this type of marginally thought out "twaddle" (good choice of words Nigel) then why not say, don't dive above 0.7 set point, even less chance of an O2 hit :rolleyes:
The USN's rebreathers were set up to run a constant 0.8-0.9 throughout the dive, they've been like that for 30-odd years.

I dive a SP of 1.0 (which on a Hammerhead is usually around 0.90-0.95) and swap to pure O2 shallow. It makes fook all real difference to your deco but makes a huge difference to your O2 exposure, it's near enough half that of running 1.3. I never do air breaks, a pure O2 loop at deco is in reality 1.4-1.5 as you offgas, combined with the low pO2 bottom phase then I'm happy that my exposure doesn't justify them. On long dives on 1.2 I notice I'm starting to feel like I'm getting a cold, sore throat/cough type symptoms and after a couple of days of that I'm ready for a break, I don't get that on lower pO2's so it's better on the pulmonary tox side as well.

As a side-benefit, you always know your cells are linear in the range you're using them before you get in the water without having to spike them on descent.

There's nothing magic about having more oxygen, the only reason to use higher levels of O2 on the bottom is to cut down on inerts. I don't think more helium is something to be scared of, certainly not at the risk of a tox or to add the hassle of carrying extra gas for air breaks or pissing O2 up the wall flushing the loop back up every 15min or whatever. For the sake of 10min extra deco?
 
1 - 20 of 34 Posts
Top