DCS and possible causes

[Bubbletrubble]

Bones have the longest half time, while blood and neural fluids are very quick.

Actually, we really don't know enough to say this.

Correlating tissues in vivo with specific half times (with respect to nitrogen on-/off-gassing) has yet to be demonstrated.

 

[The Chairman]

Then, it has been suggested by experts for a long, long time. Gud enuf for me until they come up with another theory that sounds plausible.

 

[Bubbletrubble]

Then, it has been suggested by experts for a long, long time. Gud enuf for me until they come up with another theory that sounds plausible.

I think many experts would agree that blood flow plays a role in DCS pathogenesis. In fact, you alluded to this in a previous post.

Did you know that certain kinds of bone are very highly vascularized?
Knowing this, would it change the way you are correlating theoretical tissue compartments with tissues in vivo?

My point is that unsubstantiated statements regarding DCS pathogenesis really aren't helpful. Such statements are misleading and suggest a level of certainty that we simply don't have.

 

[The Chairman]

Good enough. I guess that's why I started my participation in this thread with:

I am not a human doctor: I cure sick networks... HOWEVER,

It would be my guess...

I am proud of my humility!

 

[Puffer Fish]

I sort of keep a score card of people I have known that have had a DCS hit that are frequently called "undeserved"...while a couple seem to have no reason, most seem to involve one of two aspects:

1. Getting cold and then heating up...hot showers, hot tubs... exercise seem to be fairly common themes. Pretty simple gas laws involved in this.

2. Rapid accents.

Both of these have been difficult to prove, as we don't normally have much detailed knowledge of the body temperature or the accent rates (that is obviously changing as the technology changes).

The second item though, should be pretty obvious, as the solution to almost all gas bubble issues involves(either prevention or treatment) a slower accent... either via stops... or slow gradual release in a chamber.

Combining the two is usually not a good idea.

 

[Mr Carcharodon]

Actually, we really don't know enough to say this.

Correlating tissues in vivo with specific half times (with respect to nitrogen on-/off-gassing) has yet to be demonstrated.

I believe it has been. One of the early physiologist (I think Haldane) excised veins and explitly measured gas tension in blood returning from differnet tissues. It is a bit of an abstraction since of course a given tissue can have subcomponets with different gas solubilities. For example bubble formation in the spinal cord is observed primarily in lipid rich tissue. So if you want to divy things up at the level the model fails. Also "12 minite tissue" can be serveral disconnected sites across the body so are those all the same tissue? This is a problem of usage and not of physiology. It is a useful abstraction because it works.

 

[Bubbletrubble]

I believe it has been.

No, it hasn't.

One of the early physiologist (I think Haldane) excised veins and explitly measured gas tension in blood returning from differnet tissues. It is a bit of an abstraction since of course a given tissue can have subcomponets with different gas solubilities. For example bubble formation in the spinal cord is observed primarily in lipid rich tissue. So if you want to divy things up at the level the model fails. Also "12 minite tissue" can be serveral disconnected sites across the body so are those all the same tissue? This is a problem of usage and not of physiology. It is a useful abstraction because it works.

Yes, a given tissue can have various sub-components with different gas solubilities.
Furthermore, I do understand that when people talk about a "tissue" represented by a theoretical tissue compartment they are referring to several disconnected sites throughout the body. I don't have an issue with that.

I do recall a study of gas tension measurements on in vitro nervous system tissue (spinal cord), but this hardly approximates what occurs in vivo in a human during/after a dive. Anyone who does work with ex vivo nervous system tissue understands that the tissue is compromised as soon as it is removed from the body and, consequently, the time for studying it is finite. This window for study varies, depending on many different factors. Moreover, I'm not sure how one would use this data in making comparisons to other "tissues" (bone, fat, muscle). Yet another complicating issue is how blood shifts, which occur during/after exercise, affect nitrogen loading and off-gassing.

The abstraction of which you speak oversimplifies things and is misleading at best.

 

[Desert_Pirate]

Any Ways guys, thanks for the input, I have learned alot and with the use of a dictionary and a thessarus, I believe I got the jist of yalls conversation.

Alot of the factors you have talked about I never even thought much about being a threat, such as being cold during a dive. many of my dives are in very cold water and bein from Idaho much of the time when we get out to go home, the weather isnt much warmer. so with out any further thought we turn on the heater in the truck and speed down the road.(although we pay attention to how high the pass between us and home may be and give some time for altitude) but thanks again, I will definatley warm up a bit slower.

rapid ascents I have always been against, and to be honest I didnt even think much about physical exertion. I am an active guy and in good shape, I ask myself what about the exertion put out during the dive... In the river fighting current you endure a pretty good work out and unless you can find a rock to lie behind and hide from the current, it can get pretty demanding at times. I will for sure take advantage of those moments now.

I agree Jim, there was alot of things that should have been different, I dont like to call any one out though.

Thanks again,
Clay

 

[tracydr]

You might also consider diving with a camelback since you are diving pretty tough, dry, high altitude dives. This will help you to stay hydrated, a major risk factor in DCS. My husband and I hang one from our tanks and run the tube through the BC shoulder strap. Really takes care of the cotton mouth you get from breathing tank air. It's a very easy skill to learn to pull your erg out and drink from your camelback underwater.