Breathing rate, air integrated computers and DCI correlation

[beaverdivers]

And just for the sake of clarity, BREATHING RATE isn't even the topic -On the assumption that breathing rate is a measure of the VOLUME of gas breathed over a period of time (i.e. .4 cfm). he claim is that BREATHING FREQUENCY -the amount of breaths over time gave her "the bends". According to the original post, the BREATHING RATE was in-line for an average diver, however her BREATHING FREQUENCY was higher - she breathed the same amount of gas, just used more breaths to do it.

Correct. Her short shallow breathing caused inefficient off gasing of nitrogen resulting in DCS.

How exactly did her AI computer do this?

The Uwatec air integrated ( AI ) computer provided me with information about her post DCS dive. This dive was in a hot spring (90+ degrees F ) for 35 mins. to 50'.

She used both her non-air integrated computer that she had used during the DCS dive & an AI computer. When comparing the downloaded profile with the Uwatec non-air integrated, the AI profile was completely red. ( The non-AI computer showed a perfect dive - no alarms )

The red indicated a workload alarm throughout her entire dive. Her Surface Air Consumption ( SAC) was .4 cuft/min. Also, the physiology panel indicated that the workload was significant. The gas consumption gauge showed consistent consumption around .4 cuft/min based on a sample rate of every 20 seconds.

The consistent workload alarm correlated with the consistently low consumption indicated short shallow breathing which resulted in the bends.

Why wasn't she capable of doing this on her own.

By using this biofeedback and instruction, she was capable of correcting her breathing.

 

[ianr33]

Correct. Her short shallow breathing caused inefficient off gasing of nitrogen resulting in DCS.

And how do you know this single data point proves causation and is not merely correlation?

 

[Dr Deco]

Dear Readers:

I was asked to comment on this thread. It has many responses and I am not able to read them all [at this time]. [I will get back later. Today I have babysitting for grandchildren, grocery shopping and a blood donation. Wow]

For a short answer, however:

DCS is the result of [a] gas loads in the appropriate tissues and tissue micronuclei.

-- The gas loads are the result of blood flow to the tissues [as well as offgassing later].
-- The micronclei concentration is the result of musculoskeletal movement.

Neither of these are related to breathing rate and many factors can influence heart rate without an indication of localized blood flow.


This reply illustrates that air consmption is a easy number to measure, along with heart rate, but is only a small factor. Straining and exertion along with bottom time and depth are the major players. The other factors are "bells and whistles" but probably of doubtfull efficancy unless all other factors are constant - which they never are!

 

[beaverdivers]

I thik what BD is trying to say is that the Galileo enabled her to visualize the issue during the dive on the display and also after the dive while reviewing the downloaded data.

Remember, this event happened in the late 90's, she was using the Uwatec Air X dive copmputer. Yes, she would get a workload alarm during the dive indicating incorrect breathing. Also after a dive, we were able to give her biofeedback by downloading her dive.

 

[TSandM]

What has fascinated me in this thread is the repeated implication that a SAC rate of 0.4 cfm is high. In my experience over the last eight years, this would be low-average for an experienced female diver, and extremely low for a male. "Average" gas consumption is usually assumed at 0.7 cfm, although I know a lot of people who do better than that. I know very few who consistently do better than 0.4.

 

[beaverdivers]

What has fascinated me in this thread is the repeated implication that a SAC rate of 0.4 cfm is high.

I have indicated that her SAC of .4 cuft/min is normal or on the low side.

In my experience over the last eight years, this would be low-average for an experienced female diver, and extremely low for a male.

In my experience, .3 cuft/min is average for an experienced female diver.Yes, for males, I have found .4 cuft/min to be on the low side, but not extreme. Our new divers have an average SAC of 1.0 cuft/min. As they progress from the pool through their Open Water dives, their SAC improves. After a week long trip of diving & downloading their dives, the ave. SAC for our male divers is .6 cuft/min & for our female divers is .4 cuft/min.

"Average" gas consumption is usually assumed at 0.7 cfm, although I know a lot of people who do better than that. I know very few who consistently do better than 0.4.

Perhaps, using this "new" tool enables divers to obtain a better SAC?

Since the late 90's ( around 15 years ), I have found downloading AI computers turns out better divers with a lower risk of DCS.

 

[TSandM]

I seriously doubt that AI computers affect SAC rate. I'd be more willing to believe that they deliver lower SAC rates because they do a better job of depth averaging for doing the calculations.

Gas consumption is only amenable to conscious alteration to the extent that the breathing rate is related to anxiety or inefficient breathing patterns. Most of those are due to nervousness, and really won't resolve unless the diver becomes more relaxed. Beyond that, breathing rate is related to CO2 production, so reducing SAC rate requires becoming a more efficient diver. I don't think an AI computer can teach you better trim, or correct swimming with the hands.

 

[HIGHwing]

Mr. Beaver -

Chew on this. You do not appear to demonstrate the appropriate credentials or qualifications to state with authority that you know 1) Physiologically what happened to the subject diver 2) Whether you prevented it or provided little more than reassurance and misdirection toward a solution 3) If you actually manipulated the correct parameters involved or the modality of the DCS event in the subject. I can’t really make heads or tails of your argument, other than you’re very sure you’ve accurately diagnosed the causation, and future solution. If I understand everything, you’re advocating diving as little time as possible, using whatever factors create the shortest possible dive time. Good for you, but it's not the only path forward here.

Before we head to far up the creek and get this conversation over the dam, I think we should carefully consider a few points. Even with dives that follow the tables, we have seen a continued but statistically low incidence of DCS. We know essentially every dive is a decompression dive and that ever diver is at risk of injury just by breathing compressed air underwater. Considering what we know it’s possible we could say the subject was bent staying within the profile and likely won't be been bent again. We could also say that the subject was bent, and subsequently *discover* there is an aggravating factor like a PFO and statistically there is a likelihood to be bent again.

I don’t understand how you can answer questions with such authority, and certainty. I think your certainty is misplaced.

 

[nimoh]

I think the argument is simple. Everyone needs a dive computer that incorporates exertion in its calculations...and ScubaPro makes them

 

[beaverdivers]

I seriously doubt that AI computers affect SAC rate.

Through the info the biofeedback gives a diver, they can correct their inefficient breathing.

Gas consumption is only amenable to conscious alteration to the extent that the breathing rate is related to anxiety or inefficient breathing patterns.

Correct! Especially, if the diver is cognisant of their delima by downloading their profile.

reducing SAC rate requires becoming a more efficient diver. I don't think an AI computer can teach you better trim, or correct swimming with the hands.

Correct. However, a diver can track their progress by downloading their dives. As they become a better diver their dive profiles show improved buoyancy, reduced SAC and no alarms.

Have you ever downloaded your dive computer and analyzed your dives?

Have you ever used an air integrated dive computer?