Mike's DCS And Some Lessons Learned

[boulderjohn]

Those of you who are using tables and comparing it with total dive time may be forgetting that the bottom time as measured by the tables ends when you begin the ascent to the surface. It does not include safety stops, etc. That would be at about 35 minutes, from a depth of about 55 feet. It could also be argued that they actually started the ascent much earlier and included a 3-5 minute deep stop. In the most well known study on this, that approach was shown to be the most effective in preventing bubbling. Of course, neither the tables nor the wheel include that in their calculations.

There is a big difference between the PADI tables (the wheel) and the U.S. Navy tables. The PADI algorithm has more conservative times for first dives than the Navy tables because they were purposely designed to set up dive profiles that allowed for multiple dive days with shorter surface intervals.

It really doesn't matter, though, because they were using computers for these dives, and that included the Suunto algorithm, which has been clearly shown to be the most conservative of all the computer algorithms. It does not matter what model of Suunto was used--with the exception of its new tech computer, they all use the same algorithm. The one difference is that some models will give credit for a deep stop, while most of them will penalize for a deep stop.

 

[GrumpyOldGuy]

I don't care to debate tables vs computers, I think it is pointless. Unless you choose to not dive, you have a risk of DCS. End of story.

The interesting part of this incident is how planning treatment should be part of your dive plan, a critical plan when diving away from home. Knowing what the options are and discussing this plan with your buddies before you dive, so the plan can be implemented instantly when the 1st symptoms hit. You won't be in a place to make good decisions and relying on the dive op is iffy. The hindsight presented here knowing the delays in treatment caused both pain and probable increased injury are scary.

 

[aceupmysleeve777]

Very good post Mike B! It's nice to get this out to everyone else. Also very good reminders on checking what equipment the people your diving with have. It's very nice Mike W is making progress I'm keeping my fingers crossed it continues.

 

[miked]

Mike B:Thanks for posting. Posts like that are helpful in that it can make all of us think and hopefully be (more?) careful.

Mike W: here's hoping for a continued/complete. recovery.

 

[Mike Boswell]

I don't care to debate tables vs computers, I think it is pointless. Unless you choose to not dive, you have a risk of DCS. End of story.

Yes, and I would respectfully request that people have this "tables vs computers" discussion, if they must, on another thread.

The interesting part of this incident is how planning treatment should be part of your dive plan, a critical plan when diving away from home. Knowing what the options are and discussing this plan with your buddies before you dive, so the plan can be implemented instantly when the 1st symptoms hit. You won't be in a place to make good decisions and relying on the dive op is iffy. The hindsight presented here knowing the delays in treatment caused both pain and probable increased injury are scary.

Yes, that is really one of the main lessons - that you realistically assess your emergency treatment options and plan your dive accordingly. This would be obvious if we were diving in a truly remote location, but it isn't so obvious when diving at a dive resort.

 

[victorzamora]

Mike Boswell: I figured y'all knew to stay hydrated. Most on this board do, and most dive pros do. It was a matter of how actively did you pursue hydration? It seems like it was pursued, and the two beers aren't really enough to make MUCH of a difference. The only thing left to ask on that topic is: was there a lot of soda consumed that night or the morning before? Most don't realize how incredibly dehydrating soda can be.

As for the graph, I couldn't get it to post directly, so I Copy/Pasted into MS Paint and saved it as a picture. To get the Excel spreadsheet required me to copy/paste every line into a continuous line of data and then manipulate it from there.

I can go back through my data and find exactly when your 50-foot deep-stop stopped and started, when your ascent from 50ft started, what that rate was, and even try some multiple-line linear fits for different parts of the model. Looking through it quickly, though, it doesn't seem like your wife did ANYTHING that was considered even mildly aggressive, unless calculating it as a single-level dive per the tables.

Using the tables to do an ML-dive, I'm sectioning it up into 2 sections. I really didn't know what to do about the long/slow ascent to the deep stop, the deep stop, or the following ascent.
1) 70ft for 16min
2) 90ft for 8 min

After portion 2, you're in Group M with 5 minutes left at 90ft before your NDL. Assuming 70ft average after 90, you still have 13 minutes before NDL. Assuming 50ft, 39minutes. Assuming "ascent" between the 90ft section and the 50ft section, and including the 50ft portion as a "dive" portion and not a "stop" portion you get PLENTY of conservatism. I just don't know how to treat it. Does anyone with a computer dive planner that can do Profile-planning care to check a profile with just a few lines for fit (descent to 70ft, portion at 70, portion at 90, ascent to 50, portion at 50, and then ascent to 15ft) and share what it says?

 

[RedSeaDreamer]

Those of you who are using tables and comparing it with total dive time may be forgetting that the bottom time as measured by the tables ends when you begin the ascent to the surface. It does not include safety stops, etc. That would be at about 35 minutes, from a depth of about 55 feet. It could also be argued that they actually started the ascent much earlier and included a 3-5 minute deep stop. In the most well known study on this, that approach was shown to be the most effective in preventing bubbling. Of course, neither the tables nor the wheel include that in their calculations.

There is a big difference between the PADI tables (the wheel) and the U.S. Navy tables. The PADI algorithm has more conservative times for first dives than the Navy tables because they were purposely designed to set up dive profiles that allowed for multiple dive days with shorter surface intervals.

It really doesn't matter, though, because they were using computers for these dives, and that included the Suunto algorithm, which has been clearly shown to be the most conservative of all the computer algorithms. It does not matter what model of Suunto was used--with the exception of its new tech computer, they all use the same algorithm. The one difference is that some models will give credit for a deep stop, while most of them will penalize for a deep stop.

Awesome, you're correct and I forgot about the "begin the ascent" and it makes sense. My wife and I just purchased computers (yea I'm an old fart) and are in the learning phase; I've wondered how the algorithms jive into the old table information. This is a wonderful, informative thread. Thanks so much Mike for posting & I hope your friend can fully recover.

 

[DandyDon]

Great report, Mike. Thanks again for sharing the story and driving home some hard points so often overlooked. I do hope the best for your friend, the injured Mike.

They noted that the nearest chamber in Belize was one-and-a-half hours to the south, but doubted if it would be staffed on a Sunday, and because Xcalak’s electric system was down there was no phone service and no way to call Belize or to contact DAN. They arranged for a driver and vehicle to take him four hours north to Playa del Carmen, where the nearest reliable recompression chamber was located. They provided Mike with a second domestic-type oxygen bottle, which lasted for about three more hours.

The ride north in a small pickup truck was later described by Linda as ”horrific”, with Mike rapidly losing all function below the waist. They had to stop for military checkpoints and twice more for gas. Mike described the ride as being “Hell on Earth.” He had never experienced so much pain for such a long period of time.

I had forgotten where Xcalak was. Sounds like a delightful, remote village & dive destination to get away from the crowds & time shares of Cozumel & Playa del Carmen - with the risks you well covered. Xcalak - Wikipedia, the free encyclopedia

I don't guess a little village so remote is going to have a comfortable ambulance nor a backup generator for cell phone service. My DAN membership & dive insurance is on auto renew so I'd get an email at least if it didn't go thru, but even if you could have called DAN - I wonder if they could have done more in this case? Is there a direct road to Ambergris Caye, if you had been able to confirm that chamber was staffed? Google maps doesn't show one. If there is, I'd still be leery of taking it with an injured diver as it can't be much.

It sounds like you all did the best possible with a surprise, unexplained hit. Travel is an adventure, but that's taking it to new extremes.

 

[Johnoly]

... that you realistically assess your emergency treatment options.....

Being prepared with knowledge of those treatment options should also include IWR given how far you were from a chamber and how severe the hit was. In a spinal hit, tissue damage begins right away and continues to do damage until the bubble problem is resolved. Although admittedly controversial, if he had gone back in the water right away and followed protocols, there is a good chance he would have escaped any significant damage. If I was in his shoes and being that far away from a chamber, I would have backrolled and recompressed.

I still don't understand how on his very 1st dive of the trip his tissue compartments became over saturated.
The dive time just doesn't calc for it to happen. I'd vote a PFO or fast ascent to produce bubbles, but without a profile posted, no one will know. I hope your friend finds additional movement and healing. I have 3 friends that still years later, have severe tissue damage from spinal hits.

 

[Mike Boswell]

Great report, Mike. Thanks again for sharing the story and driving home some hard points so often overlooked. I do hope the best for your friend, the injured Mike.


I had forgotten where Xcalak was. Sounds like a delightful, remote village & dive destination to get away from the crowds & time shares of Cozumel & Playa del Carmen - with the risks you well covered. Xcalak - Wikipedia, the free encyclopedia

I don't guess a little village so remote is going to have a comfortable ambulance nor a backup generator for cell phone service. My DAN membership & dive insurance is on auto renew so I'd get an email at least if it didn't go thru, but even if you could have called DAN - I wonder if they could have done more in this case? Is there a direct road to Ambergris Caye, if you had been able to confirm that chamber was staffed? Google maps doesn't show one. If there is, I'd still be leery of taking it with an injured diver as it can't be much.

It sounds like you all did the best possible with a surprise, unexplained hit. Travel is an adventure, but that's taking it to new extremes.

We were told that Ambergris Caye could be reached by boat or by road via Chetumal. That's all I know.

Had we been able to call DAN, I think they might have helped diagnose DCS faster, and they could have advised us on whether the Belize chamber was open.

Yes, Xcalak has good diving. The coral formations are really nice, and we saw a lot of fish life there. The offshore area is a preserve, but I was told they do allow "locals" to fish, and there were numerous signs of that.