Getting DCS second time..

[tyrell]

Hello All..

According to what i red about DCS, once a diver got a DCS, the divers body gets more “sensitive” to it, and one can get a DCS more "easily" the second time.

Why is this happening

Regards

Mark

 

[Dr Deco]

Hello tyrell:

”DCS Sensitivity”

I am not aware of any studies with animals that indicate that they become more susceptible to DCS after a first DCS experience. In the case of lab animals, it is possible to increase or decrease the nitrogen “dose” to cause the appearance of DCS at will in a repeated decompression series. If the conditions are reproduced, the appearance of DCS is quite regular.

It is true that individuals (and animals) vary in susceptibility to DCS. This being true, once encountering DCS could be an indicator that you are one of the “sensitives.” One might expect that dives of a similar nature (all things being equal – including activity) would yield a similar result vis a vis decompression sickness.

”The Second Time Around”

If you should acquire neurological decompression sickness, the situation is different. Unlike love, neuro DCS is not better the second time around. Some aspects of nero DCS involve a “stroke-like” pathology. That is, there is a blockage of the blood supply and the nerves are starved for oxygen. This ischemia occurring, its persistence can lead to the death of the nerve cell. It will require the development of new neural pathways to regain function. Since there are only a certain number of pathways available for rerouting, one cannot count on complete recovery or even partial recovery.

Dr Deco :doctor:

 

[ScubaJorgen]

Remark
Individual 'Sensitivity' to DCS can be e.g. due to Patent Foramen Ovale, a shunt between two heart chambers. Normally this shunt closes after birth, in some individuals the shunt remains open. This results in (nitrogen rich) blood bypassing the lungs. Nitrogen is not removed resulting in higher susceptibility for DCS. Another reason may be being overweight. Fatty tissue is slow with respect to uptake/getting rid of nitrogen.

Question

Hello tyrell:
If you should acquire neurological decompression sickness, the situation is different.
Dr Deco :doctor:

Neuro DCS suggests the existence of 'normal' DCS. Is this true? How do these DCS's differ?

Jorgen

 

[Dr Deco]

Hello Jorgen:

”Bends” and Neurological DCS

Joint pain DCS [the bends] is a problem easily elicited in the laboratory. Under certain conditions, it is controllable and regular in its presentation. This is especially true when studying decompression to altitude. Exercise can be employed to localize joint-pain DCS to specific locations.

Neurological DCS, in contrast, is not precipitated in the lab in animals. To date, no protocol exits for producing neurological DCS in a reliable fashion in laboratory animals. This, as you might guess, makes the study of this malady difficult. It is never evoked purposely in humans in lab tests.

When neurological DCS is the result of an embolic phenomenon, there is a high degree of variability since it depends on how many gas bubbles are passed through the PFO and where these bubbles travel, i.e., the ultimate embolization site.


Dr Deco :doctor:

 

[MikeFerrara]

Dr. Deco

What do you do differently in the Lab to evoke type 1 than you would do to evoke type 2? Can you intentionally cause one without the other with a highy confidence of avoiding the other? Thanks