Breathing rate, air integrated computers and DCI correlation

[GrimSleeper]

Well, that escalated quickly...

Am I writing a thesis here? Ok I will play your condescending game. Prove to me that the technology discussed has never provided a margin of safety!

I'm sorry if you think I was being condescending. Some might see your original "your quote, I believe" as belligerent. I certainly did.

Bühlmann's models uncertain accuracy . No proof.

But lots of 'unpredicted hits' to suggest that none of the models are covering all the bases.

The information I provided was from the manufacturer of a product line that has been in production for 18 years. Yes this does not provide the empirical data you demand, it also hasn't produced a pile of dead bodies. While that doesn't prove success it does disprove failure. I'm sure the information that scubapro cites for this benefit is sales driven as is all product information.

And if changing NDLs according to breathing rate made a difference, your logic dictates that there'd be piles of corpses of people using non-AI, non-Scubapro computers. Which there aren't. I'm not saying there's anything wrong with reducing NDLs for whatever reason you want. I'm just saying that the reasoning behind basing it on respiration rate is flawed.

My observations are based on 51 years of living are this. Volume or rate or however you wish to phrase it are directly proportionally to the amount of gas dissolved in blood. My empirical proof of this is irrefutable. You don't breathe you die. You breathe too fast you pass out. So the rate/volume is related. These examples are out of the normal respiration range which is what this thread was originally about. Fast shallow respiration, and DCS.

Physics and physiology refute your irrefutable proof, alas. If you don't breathe, anoxia kills you. if you breath fast and shallow, CO2 buildup gets you. Neither has anything to do with DCS. Sorry, but I didn't write the gas laws. Maybe in four years, when I get to be 51 too, there'll be a referendum and we'll be allowed to change them. But I won't be holding my breath...

I changed my mind I am not playing your game any longer. I don't respect your opinion enough to care if you demand proof.

If you read my post, I'm not demanding anything. I'm suggesting that there are other ways to achieve an end - a reduced risk of DCS - that don't rely on shampoo-commercial pseudo-science. It's entirely up to you what you want to do with that opinion. I'm certainly not suggesting that your Galileo Luna is going to kill you, it's a perfectly good computer. I just don't accept the claim that it'll make you any safer by tinkering with NDLs when you breathe faster.


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[herbdb]

Lets put a little actual information into the discussion. This is the reasoning used for these calculations in the Gallileo Luna. It can be turned on or off as desired. I leave it on as it makes sense to me.


At the base of any decompression calculation there is the transport of nitrogen from the lungs to the blood and from there to the tissues during on-gassing, and the same again in reverse during off-gassing. As such it is obvious that the single most important parameter in a decompression calculation is the rate at which blood travels through the body. During heavy exercise, the total blood flow from the heart can be up to 4 times higher than while at rest. This increase in blood flow is rather unevenly distributed, with some tissues such as the central nervous System and the brain being unaffected, while others like the muscles receiving up to ten times more blood than at rest.

Galileo estimates the workload based on changes in the breathing pattern as detected by the hoseless high-pressure transmitter, and the decompression calculation in 4 of the 8 compartments in the ZH-L8 ADT model is changed accordingly.

 

[phoenix31tt]

^^as much as that may seem to make sense to you, breathing rate and workload are NOT proportional...

What you guys are suggesting, is that if twins dive, and perform the same activity, but one is breathing faster than the other... Then one twin would have more nitrogen loading than the other...




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[ianr33]

If I have a leak on an O ring does my NDL decrease??

 

[herbdb]

The manual clearly tells users how to turn the feature off for those who disagree with how they chose to "estimate" workload and modify the algorithum. Whats your beef? None of this is an exact science.

 

[beaverdivers]

How in the world do you make a dive plan when the Uwatec computer changes your no-stop time based on workload?

Conservatively! The Uwatec computer's have a dive plan mode. It will give you depth & time allowed based on a square profile. Almost all rec. dives today use a multi-level profile. As you ascend your No Stop time will increase allowing a diver more bottom time. However, if a diver has significant increased workload, the No Stop time will be affected & less total bottom time will be allowed.

Last edited by beaverdivers; Today at 12:30 PM

Here is the message that has just been posted:
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These dives were back in 2008. As I recall, they were about 60+ mins. each.
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Good edit! Gotta' keep the story straight.

WoW! I'm glad that you noticed. After I submitted that post, I took a quick hike. I was trying to calculate how many years that I had been using this tool of downloading air integrated dive computers minus how many years GrimSleeper has been diving. Then, I realized my mistake. I was off by a decade.

I knew I had been using this tool for 15 years, not 5 years. Nine more years than GrimSleeper had been getting wet!

But at least he is stuck diving in one of the most incredible places in the world.

I knew by his high instructor numbers, that he is new to the game.

 

[phoenix31tt]

The manual clearly tells users how to turn the feature off for those who disagree with how they chose to "estimate" workload and modify the algorithum. Whats your beef? None of this is an exact science.

the thread is about BREATHING RATE, not workload, and its effects on DCI...

And I'm waiting to see some evidence of same... BD posted his story of the woman's DCI and hinted that here computer, by virtue of monitoring breathing rate, prevented her from having a repeat case, despite the fact that she switched to nitrox and does more conservative diving.

Still waiting for something convincing to warrant me attempting to improve my breathing for something other than staying down longer (which ironically will increase my nitrogen loading)


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[GrimSleeper]

Lets put a little actual information into the discussion. This is the reasoning used for these calculations in the Gallileo Luna. It can be turned on or off as desired. I leave it on as it makes sense to me.


At the base of any decompression calculation there is the transport of nitrogen from the lungs to the blood and from there to the tissues during on-gassing, and the same again in reverse during off-gassing. As such it is obvious that the single most important parameter in a decompression calculation is the rate at which blood travels through the body. During heavy exercise, the total blood flow from the heart can be up to 4 times higher than while at rest. This increase in blood flow is rather unevenly distributed, with some tissues such as the central nervous System and the brain being unaffected, while others like the muscles receiving up to ten times more blood than at rest.
Galileo estimates the workload based on changes in the breathing pattern as detected by the hoseless high-pressure transmitter, and the decompression calculation in 4 of the 8 compartments in the ZH-L8 ADT model is changed accordingly.

That perfusion is obviously "the single most important parameter in a decompression calculation"
(a) will probably surprise a lot of researchers in the field, and
(b) suggests that it would make more sense to use something like the RNPL's 'slab' perfusion model for decompression or develop some of the work Hempleman did in the 1970s, rather than tinkering with Buhlmann's diffusion-based model.

And as others have observed, the volume of air shifted through a diver's lungs or the speed with which it's done does not necessarily correlate to the rate of bloodflow and the perfusion of tissues. By all means wear the little heart-rate monitor thingy if the Luna comes with that (and simply practising a sound ascent strategy and not pushing NDLs doesn't make you feel safe enough), and maybe it'll make a difference. But since the algorithm your computer is modifying wasn't specifically written for you, or me, or today, or tomorrow, how is tinkering with it according to breathing rate or heart rate or the alignment of the stars going to make it any more precise a predictor for what's actually happening inside the diver? Trust me, it's entirely possible to dive ZHL-8 with conservative modifications and still get very, very bent.

Are we still in Basic Scuba Discussions?

 

[Lopez116]

^^as much as that may seem to make sense to you, breathing rate and workload are NOT proportional...

Generally, aren't they relatively proportional? I.e. the harder you're working, the harder you're breathing? Maybe the Galileo is just making that general assumption and building in a conservative factor...

I've been following this thread before it split off into it's own. FWIW, I don't have a dog in the fight here, I'm just trying to learn...


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[phoenix31tt]

Workload Increases breathing, not the other way around... I can sit very still and increase/decrease my rate of breading without increasing my workload.





I dont have a horse either, but the "evidence" presented for saying breathing rate affects dci thus far are rather poor..





I'm all about learning at this point



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