NEDU Study

[Schwob]

@ScubaBoard:
Can we get an "unlike" button or an "report post" button or something to put an end to this misery?

 

[RainPilot]

@ScubaBoard:
Can we get an "unlike" button or an "report post" button or something to put an end to this misery?

There is a report post button for TOS violations. No unlike button yet.

 

[fsardone]

The nedu test had this problem too. But with an extra twist. One diver was average 15 ft difference at any given point in the middle 2 hours (1/2 an ATA imbalance for the same core temp).


Why the different outcome? Different gas loads.... as predicted by existing basic gas kinetic formula. (The same basic formula as used in existing models).

Hope that answers it.
.

Ross it does not answer it unfortunately.

The gas load is the same (same bottom time) and the time in decompression is the same.
The only difference is how that decompression time has been distributed in the two profiles.

In three different thread on different boards it has been argued that staying deeper longer would keep on gassing the slow tissues while limiting the supersaturation of the fast ones. At the same time it has been argued that going shallower sooner would increase the supersaturation of the fast tissue (which are more resilient to it) and limit the on gassing of the slow tissues. All of this off the experience from the NEDU study, which proved the latter strategy to have less DCS.

Now are you saying that the different (higher) gas load is due to staying deeper longer? and therefore to avoid bad outcome we should go shallower sooner? Because if you are saying so we all agree.

Cheers

 

[rossh]

Ross it does not answer it unfortunately.

The gas load is the same (same bottom time) and the time in decompression is the same.


The only difference is how that decompression time has been distributed in the two profiles.

In three different thread on different boards it has been argued that staying deeper longer would keep on gassing the slow tissues while limiting the supersaturation of the fast ones. At the same time it has been argued that going shallower sooner would increase the supersaturation of the fast tissue (which are more resilient to it) and limit the on gassing of the slow tissues. All of this off the experience from the NEDU study, which proved the latter strategy to have less DCS.

Now are you saying that the different (higher) gas load is due to staying deeper longer? and therefore to avoid bad outcome we should go shallower sooner? Because if you are saying so we all agree.

Cheers

Hi,

"are you saying that the different (higher) gas load is due to staying deeper longer? "

Yes...... Always have said that. It's plain basic ordinary gas kinetics formula..... no arguing with that. That is intrinsic to all models.

Note that All existing models make longer deco shallow times in response to more deeper time. i.e. nothing broken, nothing to fix. Note this on gas deeper stop argument is a small amount in real profiles. It doesn't need extra GF manually patched onto the end.


What happened in the nedu test is NOT what happens in real dives (VPM or GF). The strategy you mentioned, was not tested. (more on this later) So.... be careful trying to read to much into the nedu profiles. No deep stops, no "protecting" as claimed, no similar sup sat patterns...etc.

 

[PfcAJ]

Hi,

"are you saying that the different (higher) gas load is due to staying deeper longer? "

Yes...... Always have said that. It's plain basic ordinary gas kinetics formula..... no arguing with that. That is intrinsic to all models.

Note that All existing models make longer deco shallow times in response to more deeper time. i.e. nothing broken, nothing to fix. Note this on gas deeper stop argument is a small amount in real profiles. It doesn't need extra GF manually patched onto the end.


What happened in the nedu test is NOT what happens in real dives (VPM or GF). The strategy you mentioned, was not tested. (more on this later) So.... be careful trying to read to much into the nedu profiles. No deep stops, no "protecting" as claimed, no similar sup sat patterns...etc.

Quoting this so you can't go back and edit it later.

 

[victorzamora]

As the deco progresses, it has Increasing thermal stress, and reducing profile stress. One stress is going down and the other up.

The little bit of cold we all get, is usually small and not enough to make trouble.

But get a flood and make some body part very cold, and its a big thermal stress. Or sit naked loosing core temp for 4 hours (nedu test). Under those conditions, its a race, between getting enough of the gas out of tissue, before the cold slows down the circulation preventing the tissue off gassing sufficiently. Adding more deco time (and thermal stress) will not solve this condition, but instead make it worse. A bucket curve.

I'm sorry, Ross, but I'm not following again. I might have misunderstood the physiology, but I don't think a bucket curve accurately describes it.

If you get cold during deco, LESS deco isn't the solution. If I've already done the bottom time and racked up a certain amount of deco, there's no bucket curve. There's no benefit to ascending early. At all.

 

[Ayisha]

Hi,

"are you saying that the different (higher) gas load is due to staying deeper longer? "

Yes...... Always have said that. It's plain basic ordinary gas kinetics formula..... no arguing with that. That is intrinsic to all models.

Note that All existing models make longer deco shallow times in response to more deeper time. i.e. nothing broken, nothing to fix. Note this on gas deeper stop argument is a small amount in real profiles. It doesn't need extra GF manually patched onto the end.

What happened in the nedu test is NOT what happens in real dives (VPM or GF). The strategy you mentioned, was not tested. (more on this later) So.... be careful trying to read to much into the nedu profiles. No deep stops, no "protecting" as claimed, no similar sup sat patterns...etc.

(bold and colour added)

OMG, finally, we have a revelation. Does that mean we can stop all this nonsense now in the way of multiple deep stop threads going in the same circles? It's past time to let our incredibly patient deco scientists do their important work without these distractions.

 

[fsardone]

Hi,

"are you saying that the different (higher) gas load is due to staying deeper longer? "

Yes...... Always have said that. It's plain basic ordinary gas kinetics formula..... no arguing with that. That is intrinsic to all models.

Note that All existing models make longer deco shallow times in response to more deeper time. i.e. nothing broken, nothing to fix. Note this on gas deeper stop argument is a small amount in real profiles. It doesn't need extra GF manually patched onto the end.


What happened in the nedu test is NOT what happens in real dives (VPM or GF). The strategy you mentioned, was not tested. (more on this later) So.... be careful trying to read to much into the nedu profiles. No deep stops, no "protecting" as claimed, no similar sup sat patterns...etc.

Thank you for your reply,
is really good that we all agree here. It must have been lost in the background noise ...

Cheers

 

[shoredivr]

(bold and colour added)

OMG, finally, we have a revelation. Does that mean we can stop all this nonsense now in the way of multiple deep stop threads going in the same circles? It's past time to let our incredibly patient deco scientists do their important work without these distractions.

I've learned a lot from these threads and the excellent responses from the decompression scientists, though. I appreciate all they have shared.

 

[nadwidny]

(bold and colour added)

OMG, finally, we have a revelation. Does that mean we can stop all this nonsense now in the way of multiple deep stop threads going in the same circles? .

Apparently not. As long as the owners of the forums invite more of the Ross vs Everyone threads to continue in order to drive their traffic count up and make them more money, we can all look forward to more of this crap, over, and over, and over.