Getting bent again...what's the story

[Web Monkey]

From reading Dr. Deco's answer and a couple of other threads, it sounds like if you got bent, you stand a good chance og getting bent again if you do the same things in the same way. Not because you got bent the first time, but because whatever circumstances caused to you get bent the first time will probably cause you to get bent again if they exist the second time.

It's not much comfort, and sounds a little like lightning strike locations. If something gets hit once, and conditions stay the same, there's a good probability of a second hit. Not because of the first hit, but because of the conditions that caused the first hit.


Terry

This really was a thorough response from Dr. Deco. But I felt I never got closure ... so after searching around and not finding a thread that really nailed this down I'm going to try rephrasing the question:

Does getting bent once increase susceptiblity even in the absence of all other "Trouble Spots"?

Is there a case where a non-susceptible diver who was bent previously for hitting a "Trouble Spot", later got bent again but no "Trouble Spot" or susceptibility could be identfied?

 

[DiverBuoy]

Agreed. Getting hit does not sensitize you to future hits. Getting hit does tell you one of three things - you might be a susceptible-to-DCS diver, you encountered one of Dr Deco's Hotspots, or a classicly well-known provocation. If the cause cannot be eliminated for future dives, consider diving conservatively on a permanent basis, or abstenance.

 

[Puffer Fish]

Dear Diver Buoy:

Preselection

During the Second World War, it was demonstrated that an effective countermeasure to altitude decompression sickness (“flyers’ bends&#8221 was preselection of susceptible individuals . This was done by putting the candidates for high altitude bomber crews in an altitude chamber and exposing them to reduced pressure for a period of time. Those who were able to pass this test were deemed to be resistant to DCS.

DCS Susceptibility – Is It Real?

Extensive test programs at various centers around the United States demonstrated that

• some individuals were definitely more susceptible to the effects of pressure reduction,
• this susceptibility was constant over days to weeks to months, and
• it could be altered by physical exercise.

I bet that no one who reads this FORUM would have guessed all of those – “Right!” [The references for this work are not easy to obtain since was performed fifty years ago and requires a university library.]

“Once Bent – Twice Shy”

It is a possibility that you are a “susceptible.” It is also possible that you encountered some of Dr Deco’s “Trouble Spots.” :nono:

These would be

• excessive exercise at depth and too much inactivity at the surface (bad gas load/unloading characteristics,
• climbed ladders onto the boat with heavy gear and [excessively] nucleated yourself,
• performed too much strenuous activity during the surface interval [nucleation],
• were under hydrated and thereby lower the surface tension of your body’s fluids.

Conservative decompression is required in the future – and I do not mean just staying within the table “limits.” There are not really any “limits” in a biophysical sense.

Dr Deco :doctor:

You can go back even farther to the original discovery of Caisson's disease, where there were some people that never got it, some that got it some of the time and some that got it very quickly and almost with any exposure.

I think I still have reprints of that Navy study, printed in the 60's.

I've seen two individual's with a tremendous tendency to develop DSC, one had to have three events before giving up diving. The last one was during two 60 ft dives, each lasting less than 30 minutes, with a three hour surface interval. He was with 5 others, none of which had any issue.

There is a major difference between statistics of a population and the effects on an individual. If an individual has a DCS event, they are now part of the DCS population. This could be from one or a combination of:

1. A tendency to get DCS
2. Doc's issues listed above.
3. Equipment inaccuracies (is 89 feet on a computer actually 89 feet?)
4. Outside effecting events (a major low pressure center, for example)

Because of this, it is clear that this new population will have a higher percentage of additonal events. That does not, however, mean very much for a specific individual, unless they know exactly why they had the event. For the most part, this is not an exact science today.

 

[Dr Deco]

Hello readers:

DCS Prone

We are all aware that “blood chemistries” and stroke only correlate for a group as a whole. Many people with very “good numbers” have heart attacks and strokes and some with terrible numbers are not affected. It is said that such variability is why insurance companies make more money than fortunetellers.

Diving in the field is not the same as diving in a laboratory setting. Even lab subjects will have variabilities that cannot currently be explained.

Canaries

Those who test dive tables are aware that certain individuals in their pool of subjects are more sensitive than others. This person will often be called a “canary” (such as miners once carried to warn of hazards). These people are the last to be tested and are proof that the table is good.

Recreational divers will also have “canaries” amongst them. Some folks really are not suited to a “regular” dive table. A hit on an otherwise normal profile should make one suspicious. :14:

Dr Deco :doctor:

 

[Puffer Fish]

Hello readers:

DCS Prone

We are all aware that “blood chemistries” and stroke only correlate for a group as a whole. Many people with very “good numbers” have heart attacks and strokes and some with terrible numbers are not affected. It is said that such variability is why insurance companies make more money than fortunetellers.

Diving in the field is not the same as diving in a laboratory setting. Even lab subjects will have variabilities that cannot currently be explained.

Canaries

Those who test dive tables are aware that certain individuals in their pool of subjects are more sensitive than others. This person will often be called a “canary” (such as miners once carried to warn of hazards). These people are the last to be tested and are proof that the table is good.

Recreational divers will also have “canaries” amongst them. Some folks really are not suited to a “regular” dive table. A hit on an otherwise normal profile should make one suspicious. :14:

Dr Deco :doctor:

Well said Doc -

 

[made for it]

Dear all,
I agree with a lot of elements brought up through out this discussion, however as you know there are SO many different contributions to being susceptible to DCS, whether it was on the day dehydration, poor profiles or pre-medical issues.

Nerve damage from bubbles can very dramatically, depending on where they do the damage and the severity of the damage done. HBOT is essential to "try" and correct the damage or encourage re-growth within the nerves and getting oxygen to Hypoxic areas, quicker the treatment is implemented higher the possibilities of resolution.

Being susceptible to a second encounter to DCS is a risk factor when you re-enter the water on scuba. Theoretically nerve damage has occurred from the previous encounter of DCS, so more susceptible to damage again “IF” another bubble returns to that area. Using a “heart attack” as previously used as an example- you are in a higher risk category of having another heart attack. However it does not mean you will have another heart attack! Many of my friends post – DCS have done hundreds of dives with in the dive industry with no problems.
Re-entering the water before damaged tissues have recovered can severely damage that area as far as permanently.
How many divers had DCS the second time round, went diving before they were advised by a DMO not to enter or the diver was diving with signs and symptoms going on?

Made for it,
Diver Medical Technician (DMT)

 

[DiverBuoy]

Dear all,
I agree with a lot of elements brought up through out this discussion, however as you know there are SO many different contributions to being susceptible to DCS, whether it was on the day dehydration, poor profiles or pre-medical issues.

Nerve damage from bubbles can very dramatically, depending on where they do the damage and the severity of the damage done. HBOT is essential to "try" and correct the damage or encourage re-growth within the nerves and getting oxygen to Hypoxic areas, quicker the treatment is implemented higher the possibilities of resolution.

Being susceptible to a second encounter to DCS is a risk factor when you re-enter the water on scuba. Theoretically nerve damage has occurred from the previous encounter of DCS, so more susceptible to damage again “IF” another bubble returns to that area. Using a “heart attack” as previously used as an example- you are in a higher risk category of having another heart attack. However it does not mean you will have another heart attack! Many of my friends post – DCS have done hundreds of dives with in the dive industry with no problems.
Re-entering the water before damaged tissues have recovered can severely damage that area as far as permanently.
How many divers had DCS the second time round, went diving before they were advised by a DMO not to enter or the diver was diving with signs and symptoms going on?

Made for it,
Diver Medical Technician (DMT)

Hmm that's an interesting perspective. Do you have any medical documentation references or materials to support this conclusion?

 

[Dr Deco]

Hello readers:

I was a way for sever weeks at a location without a functioning internet connection. It was not what I originally expected. I am back home again.

I have definitely heard of divers reentering the water when they already had problems of DCS. This is clearly not a good idea – nor should one fly when DCS symptoms are evident.

Dr Deco :doctor:

 

[dreammermaid]

I find this discussion of interest as I am now in the 'dcs' group. I got dcs 11 after a deserved hit. Dragged down very deep, came up without deco stops. I recently made my 1st pool dive since the accident 11 months ago. I have decreased feeling a bit in my legs and numb ankles. Still getting better everyday. Previously I was an instructor and loved my job.

I've wondered about the chances of getting another hit. I know if you get one the chances of recovery are decreased. I love diving and want to continue but trying to figure out the safest way to return has been conflicting. Some people I heard from just 'got back to diving'. Others did extensive pool dives on high o2 first. A friend of a friend made his first dive 50 feet for 45 minutes and got bent again so I definitely want to be more conservative in the beginning. But then I know everyone is so different you can't generalize. Anyone had experience returning to diving after dcs?

 

[MonkSeal]

A friend of a friend made his first dive 50 feet for 45 minutes and got bent

I can hardly believe that this can happen without additional physiological cause. Sorry, but it looks more like "friend of friend" type of story.