DCS--Playing the Odds

[RainPilot]

I think that is what age has brought to compensate ..

Old divers and bold divers...

 

[Akimbo]

Old divers and bold divers...

I am living proof that some young bold divers are capable of learning, which is the more favorable remedy of the bold/ignorant condition. I may follow some practices that newly trained recreational divers are taught are forbidden; but only because I was taught how to safely execute them. The old saying about no old bold divers is enforced by Darwin, even if he cuts a few of us some slack on the first few infractions.

"The great majority of the cumulative knowledge presented in diving classes at all levels resulted from accidents that scared the hell out of, injured, or killed someone. Thanks to all the pioneers the preceded me, living or not."

 

[RainPilot]

We all started bold. Some of us got to get old.

Those that did, lot less bold now.

 

[JohnnyC]

The older I get, the bigger the dives I do. Did 4 hours in the cave yesterday on the loop, including 20 minutes of deco. However, I find that I'm significantly more risk averse in how I plan and execute those dives the older I get. The dives may be bolder, but the things I do to hedge my bets against an issue has certainly matured as well. One day the scale will tip and the dives will get less bold, but I don't really see any reduction in risk management.

 

[boulderjohn]

The older I get, the bigger the dives I do. Did 4 hours in the cave yesterday on the loop, including 20 minutes of deco. However, I find that I'm significantly more risk averse in how I plan and execute those dives the older I get. The dives may be bolder, but the things I do to hedge my bets against an issue has certainly matured as well. One day the scale will tip and the dives will get less bold, but I don't really see any reduction in risk management.

I am pretty old, and I don't think I am bold. I think, however, that some people would accuse me of boldness, because what looks bold to some people does not seem bold at all to others. I have done a bunch of training dives this past fall. Of the ones that were just personal pleasure dives, every one of them was 200 feet deep or more. Eight of them averaged about 270 feet.

To some, those numbers seem bold, but I don't believe they are. They are carefully planned, and they are well within conservative limits of the algorithm I use. I have the certifications required for those dives, as do my buddies. I am not doing anything tricky or risky at those depths--mostly just exploring areas I haven't seen before to find out what is there. I respect the inherent danger in the dives I do, but I do not feel a hint of fear before a dive. I don't think you can call yourself bold if you do not have a reasonable fear about what you are doing.

I friend who is an avid mountain climber told me that in the early days of mountain climbing, when people were first scaling Everest and K2, the fatality rate on those record climbs was close to 1 in 3. those people knew that when they started the climb. I don't know anyone in scuba who is in that class of boldness.

 

[KenGordon]

Exactly. You would likely conclude that you are not DCS prone, and the dive algorithm you are following is very much right for you. Your next dive will thus very likely be a safe one.

I know several people who have been found to have PFOs after many years of successful regular (British) diving. This follows unexplained (by profile) bends. By the logic aboveboard those people will have concluded they are not susceptible.

 

[Neilwood]

I am living proof that some young bold divers are capable of learning, which is the more favorable remedy of the bold/ignorant condition. I may follow some practices that newly trained recreational divers are taught are forbidden; but only because I was taught how to safely execute them. The old saying about no old bold divers is enforced by Darwin, even if he cuts a few of us some slack on the first few infractions.

"The great majority of the cumulative knowledge presented in diving classes at all levels resulted from accidents that scared the hell out of, injured, or killed someone. Thanks to all the pioneers the preceded me, living or not."

That is well worth emphasising - most of the knowledge (especially from the early days) came from people being hurt or dying and others trying to figure out why. The more recent knowledge has built upon those dearly paid lessons.

One of the definitions of insanity is "repeating the same mistakes and expecting a different result". If I know someone else made that mistake, why do I want to make it as well?

That is why we should all try to learn every time we get in the water. Asking simple questions like the following are a good start:
Is there something I could have done better?
Did I feel anything unusual physically after the dive?
Was I a good buddy?
Was my ascent/descent safe?
Are my skills up to date?

 

[Neilwood]

I know several people who have been found to have PFOs after many years of successful regular (British) diving. This follows unexplained (by profile) bends. By the logic aboveboard those people will have concluded they are not susceptible.

There will always be a small amount of "underserved" hits until we, as human beings, know absolutely everything there is to know about human physiology, our exact physical state (including any hidden medical issues such as PFO, cardiac , pulmonary, circulatory etc) every time we enter the water and exactly what we are going to do underwater (exertion level, ascent rates, breathing rates). Only with that knowledge can an algorithm be devised that would take every factor into account and alter the parameters of the dive accordingly instantly. Is that situation every likely to happen? Probably not as the level of investment required for the algorithm alone would be immense never mind the diagnostic machinery/skill required to determine the physiological state of the diver (at the time of entering the water and during the dive). It might be possible if a handheld medical tricorder ever becomes available (I am only slightly kidding here).

What we can do is minimise the likelyhood of DCS by trying to load the dice in our favour by selecting a conservative profile, being conservative in our profile, following guidelines about hydration, sleep, general health etc, staying reasonably up to date about DCS research etc.

I could buy a diving computer with a "liberal" algorithm and dive it on its most aggressive setting? Would that be a good idea for a reasonably healthy 45 year old? Probably not as good an idea as it would be for someone of 20 who does triathlons for fun. Better IMHO as I get older to move to a more conservative option.

 

[MargaritaMike]

Is that situation every likely to happen? Probably not as the level of investment required for the algorithm alone would be immense never mind the diagnostic machinery/skill required to determine the physiological state of the diver (at the time of entering the water and during the dive). It might be possible if a handheld medical tricorder ever becomes available (I am only slightly kidding here).

I think ScubaPro has kind of moved in this direction with the Heart Rate monitor. My guess is that it won't be long before other manufacturers incorporate this process and then add to it in some way. It would seem that this could be accomplished with a firmware update. (Shearwater, are you listening?) Until this happens I plan to dive a conservative setting conservatively.
On a side note, I think this thread is becoming somewhat repetitious with almost everyone saying the same thing in a little bit different ways.
Just my $.02
Cheers - M²

 

[KenGordon]

There will always be a small amount of "underserved" hits until we, as human beings, know absolutely everything there is to know about human physiology, our exact physical state (including any hidden medical issues such as PFO, cardiac , pulmonary, circulatory etc) every time we enter the water and exactly what we are going to do underwater (exertion level, ascent rates, breathing rates).

These are hard things to know. Today we could screen for PFO but do not. Some thing make sense and have a worthwhile return, some not. My point is that a given diver does not know their own personal risk so ought to dive in a conservative fashion regardless.