Effects of long term pressure

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DrSteve

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I've just been reading a book on skin physiology and it brought up something I had not considered before. Pressure can cause compression of the intercelluar spaces and ineffective draining of the lymph nodes which could ultimately lead to necrosis. Clearly this is the cause for such conditions as bed sores...but I am wondering what the long term effects are on saturation divers? What about the studies which our Lord the great JC did in his conshelf living experiment?

Just curious :)
 
Hello DrSteve:

Hydrostatic Pressure

Pressure can indeed cause all manner of nasty things. When the body is subject to uniform increased pressure, however, the situation is a bit different. There are not any fluid shifts with uniform pressure over all body.

Remember that we are at the bottom of an “ocean of air” and subject to 14.7 psi at all times. An average individual has a body surface of 19.4 sq. ft, and with one atmosphere of pressure, this equates to 41,000 pounds on the entire body. This is a very large force, but it is applied equally.

The pressure on an individual in a pressure chamber, or a diver in the water, is also applied evenly. There is not any shift of fluid from this. Id you were to stick your hand into some small pressure chamber with a suitable seal around the arm, pressurizing this would cause the blood to be squeezed into the body from the extremity.

Bed Sores

In the cause of decubitis ulcers [bed sores], the individual is lying on parts of the body and preventing adequate perfusion. Sores develop because the person never moves around, as do you or I. People in such situations must be turned do prevent this problem.

Dr Deco :doctor:
 
Thanks Dr Deco. OK the even pressure makes sense. But even if the pressure is even it is still greater than we are built to deal with, so wouldn't it cause a lot of the body (not just the skin/lymphatic system) to effectively be crushed and cause problems? As I recall the long term astronauts found they had water accumulation in unusual areas without gravity, along with all the other problems like loss of bone density.
Thanks.
 
I read in an article at least 3 years ago now (Immersed maybe) about the effects on long term satueration divers who have worked for 2 or more years, were having lesions on/in their brain tissue found. The folks in the study had not seemed to have short/long term memory loss as of yet if I remember correctly. The folks doing the study were unsure of the overall effects of the lesions. It was awhile ago when I read it, so I could be getting it wrong. Anyone know or heard of this?
 

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