Mike's DCS And Some Lessons Learned

[Lorenzoid]

There is no such thing as an undeserved hit IMO.

Just because your dive profile is correct, does not mean you are safe. Age, physical health, hydration, immune systems, PFO/shunts, bruising of muscle/skin/ligaments/bones, medication, flu, drugs/alcohol, bumpy boat ride/bad posture, body fat, sleep, ambient temp, acclimatisation to name just a few can impact the outcome of a DCS hit, even within safe dive parameters.

Stay at ground level if you want to remove DCS, don't go up or down.

Wow--I just read this thread but wish I had seen it earlier.

I might have overlooked it, but was Mike (the victim) checked for PFO? I also might have overlooked it, but was it mentioned whether he had any other predisposing factors? The "two beers" many hours earlier was mentioned, but did he feel adequately hydrated in his opinion? Was he in good physical shape?

If this is truly a case of DCS arising from something other than an unsafe dive profile, it should get more attention here. I have seen too many people here seemingly wave off the odds of taking a DCS hit as infinitesimal, complaining that their Suunto computers are needlessly conservative, etc. People should know that it really can happen. DCS is probabilistic, and you really can win the lottery, so to speak.

 

[Mike Boswell]

Wow--I just read this thread but wish I had seen it earlier.

I might have overlooked it, but was Mike (the victim) checked for PFO? I also might have overlooked it, but was it mentioned whether he had any other predisposing factors? The "two beers" many hours earlier was mentioned, but did he feel adequately hydrated in his opinion? Was he in good physical shape?

If this is truly a case of DCS arising from something other than an unsafe dive profile, it should get more attention here. I have seen too many people here seemingly wave off the odds of taking a DCS hit as infinitesimal, complaining that their Suunto computers are needlessly conservative, etc. People should know that it really can happen. DCS is probabilistic, and you really can win the lottery, so to speak.

Yes, Mike was in good shape, is a conservative diver, is a DM, has been diving for four decades, and had done this same dive in past visits. We were well aware of the danger of dehydration, we discussed it, and we made efforts to avoid it. No, Mike has not been checked for a PFO.

Yes, it seems to be the case that the nitrogen loading limits given in tables or computer algorithms are set to produce an acceptable balance between dive time and risk of DCS. This means that you DO have a small but finite risk of DCS.

 

[Kevrumbo]

When we were diving the wrecks in Chuuk last year, our DM (Cindy) explained to us that we would be doing regular decompression stops on every dive - 3 minutes at 30 feet and 10 minutes at 15 feet, as an added safety precaution, even though our dives were within NDLs. I remember thinking this was being overly cautious: Boy, was I wrong!

For an interesting read about diving in exotic locations, see Alert Diver | Bent in Chuuk

I know this extra conservative profile is standard procedure for the recreational divers on the Truk liveaboard Thorfinn, and continues to be applied by Cindy and Rob -former Thorfinn Dive Guides- & now the managers at the Truk Stop Hotel dive-ops.

With regard to the wreck dives in Truk, you tend to load & saturate the slow tissues in general on repetitive dives over a week's time (note that the slow tissues are responsible for most type one DCS pain only events), so it's good practice to extend out that shallow "safety stop" on backgas Air, Eanx30 or 32. (A more efficient method is to extend that safety/deco stop at 6m by a switch off backgas to 100% Oxygen, but that requires Advanced Nitrox & Decompression Procedures certification, something IMO that Mike should now consider as a future option).

 

[Mike Boswell]

Mike, can you remember anything else regarding the pre-dive preparations? Did you take any cold or allergy medicine the previous night? How much caffeine did you have before diving? Are you a coffee drinker? I wonder if the cramped conditions after the dive had any impact?

I just heard from Mike - Yes, he had 2 cups of coffee that morning (Katy and I did also). No, he didn't take any medicines. We don't know whether the cramped conditions in the boat after the dive played a role in his DCS.

However, the cramped conditions led us to think that Mike's numbness on his side and shoulder might be due to rubbing and bouncing against the side of the boat.