Mike's DCS And Some Lessons Learned

[Mike Boswell]

Thanks, Scubadada.

The data I presented can be a little deceiving if you try to get too much fine detail out of it. For example, at the end of the dive we show an abrupt ascent from 14 feet to zero feet in ten seconds. This would indicate an ascent rate of 6 x 14 = 84 feet per minute. However, this actually is not what happened. I'm not sure how the Suunto captures it's depth information for each ten-second segment (it could be an average depth over that ten seconds, or the depth at the beginning or end, or midpoint, or whatever), but I am sure - because I watch her and sometimes film her - that Katy rises very slowly from the safety stop to the surface.

Another "deceiving" aspect of graphs can be the selection of the X and Y scales, which can make gradual vertical movements look abrupt.

---------- Post added December 21st, 2013 at 01:01 PM ----------

As a new diver I like to read these posts to try and help avoid problems, but reading this post over again has kind of made me nervous now.
What are the statistics on the likelihood of sustaining an undeserved hit?

Perhaps you will get some answers in this DAN article - I thought it was very informative: Alert Diver | Conservative Diving

 

[FinnMom]

A very scary story. Maybe the scariest part is what the presentation of so many theories is trying to avoid: undeserved hits happen. Just because the chances of something might be 1/10,000,000 doesn't mean that it doesn't happen. We've all noticed that folks do win the Mega Lotto now and again haven't we? Beating the odds happens, and it isn't always a good thing (I remember studing Genetics 30 yrs ago: catching the wild, long-shot odds in Genetics was usually a very bad piece of luck).

I'm taking from this the fact that just being middle aged and not-svelte is already 2 risk factors for me. I should give more thought to precautions
* Longer safety stops might be a good idea - could always be combined with som other kind of drill to pass the time, add to the benefit and keep a buddy amused.
* Need to remember the importance of rising that last 6-3m SLOWLY (with capitol letters)
* Need to be more religious about taking along O2 on our outings & making sure a hired boat has O2 issue appropriately handled (condition, amount, etc.)
* Need to remember the power of denial/risks of optimism when confronted w/ possible DCS

I'm so exceptionally happy to hear that things are going better for Mike & hope he makes a full recovery!

 

[Steve A]

Thanks Mike just had a good read and understood most of it. As a future precaution and to help me relax a little, I am going to dive nitrox but keep my dive computer set to air so I feel like I am diving very conservatively and restrain from diving over 25m. We have only logged 38 dives each (all in the red sea) so me and the wife are novices but can see enough marine life if the first 10-20m to keep us entertained. Thanks again for all the info shared.

 

[Mike Boswell]

A very scary story. Maybe the scariest part is what the presentation of so many theories is trying to avoid: undeserved hits happen. Just because the chances of something might be 1/10,000,000 doesn't mean that it doesn't happen. We've all noticed that folks do win the Mega Lotto now and again haven't we? Beating the odds happens, and it isn't always a good thing (I remember studing Genetics 30 yrs ago: catching the wild, long-shot odds in Genetics was usually a very bad piece of luck).

I'm taking from this the fact that just being middle aged and not-svelte is already 2 risk factors for me. I should give more thought to precautions
* Longer safety stops might be a good idea - could always be combined with som other kind of drill to pass the time, add to the benefit and keep a buddy amused.
* Need to remember the importance of rising that last 6-3m SLOWLY (with capitol letters)
* Need to be more religious about taking along O2 on our outings & making sure a hired boat has O2 issue appropriately handled (condition, amount, etc.)
* Need to remember the power of denial/risks of optimism when confronted w/ possible DCS

I'm so exceptionally happy to hear that things are going better for Mike & hope he makes a full recovery!

The owners of the dive operation told me that this was the first time in 29 years of operation that they had seen a case of the bends. I believed them, and this is undoubtedly why they were unprepared for Mike's emergency. But as you point out, the odds of a few cases per 10,000 dives means it WILL happen eventually.

Here is the website of the chamber on Belize. Belize Diving, Hyperbaric Chamber on Ambergris Caye, San Pedro They say they treat 2 or 3 cases per month.

The Belize chamber is 26 miles to the south of Xcalak.

 

[Eric Sedletzky]

In re-reading this thread it occurred to me that it sounds like I wrote the OP. Actually, Mike and Linda wrote most of it, and I just tidied it up a bit. So any thanks you all have should go to Mike and Linda.

Changing the subject a little, I'd like to hear from those who have information about the recovery process from nerve damage.

How does it work? What therapies help? Why does it take so long? Is there any information out there that would be helpful to Mike?

I had a Transverse Myelitis (sp) about 8 years ago now. That is when the myelin sheath around the nerves gets fried and the nerves short out.
This happened in my neck. I couldn't feel my skin over most of my body from the collar bones down. My hands were the worst. I hadn't been diving in over a month so at least I knew it wasn't DCS.

It took about 6 months for most of the symtoms to clear and about a year for nearly all of them to clear and the few I have left I'm stuck with.
9 MRI's and a spinal tap and they still couldn't tell me why it happened.
They told me to eat a lot of omega 3's.
Other than that there's not much they can do.

DCS might be different since bubbles can kill nerves. Maybe with myelinitis it heals better because the myelin sheath is affected but the nerve doesn't necessarily die.
Lynne would know more, I'm just parroting what they told me.

 

[Mike Boswell]

Thanks Mike just had a good read and understood most of it. As a future precaution and to help me relax a little, I am going to dive nitrox but keep my dive computer set to air so I feel like I am diving very conservatively and restrain from diving over 25m. We have only logged 38 dives each (all in the red sea) so me and the wife are novices but can see enough marine life if the first 10-20m to keep us entertained. Thanks again for all the info shared.

Another way to do this would be to use your conservatism settings on your computer. For instance, when using Nitrox with 32% Oxygen, I can set my Suunto to the P2 setting and get very nearly the same NDL's as I would get on the AIR setting (see table below). By doing it this way I wouldn't be losing the Nitrox features on my computer such as the depth limitation.

	SETTINGS		NDL (Minutes)
Model	%O2	A	P	30	40	50	60	70	80	90	100	110	120	130	140	150
Air	21	0	0	---	120	69	50	36	28	22	17	13	10	9	7	6
Nitrox	32	0	2	---	121	66	45	32	25	21	17	---	---	---	---	---

 

[acteg]

Thanks for posting. A good reminder to evaluate all aspects of a dive/dive operator (including there capability to handle an emergency/proximity to a chamber), understand the risks, and err on the side of caution when dealing with abnormal post dive symptoms. I'm sorry to hear of Mike's story, but am glad to hear that he is making a positive recovery.

 

[Hatul]

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.

A comment about the Suunto algorithm. On the last two Cozumel trips I dove with both my Uwatec Galileo and Suunto Vyper. I found my Galileo more conservative than the Sunnto on the first dive of the day. It was on repetitive diving that the Suunto became more conservative.

 

[Mike Boswell]

That's a scary story. I have lost count of the times I have dived and not checked on emergency prep at a dive op other than "do you have oxygen" type of questions. As with many guys, I also tend to discount initial symptom and think they will go away if I tough it out like a man.

Sounding more like 2 strikes to me now.

I have lost count of the number of examples of poor maintenance and broken equipment I've seen at dive ops. All dive ops like to talk about their facilities and capabilities, but, particularly when profits are down, many are tempted to cut costs on things like maintenance.

I also think we divers feel, when we are showing cert cards and reading and signing releases, that we are the ones who must carry the burden of proof in regards to safe diving. But Mike's incident has taught me that safety is a two-way street, and that we divers have our own "due diligence" responsibilities to perform.

 

[Steve A]

Being relatively new I have never thought to ask about first aid facilities and when on a boat with other more experienced divers thought it was 'safe'.
Having dived with three different operators I can only remember one that has ever briefed us on where the first aid and oxygen are kept and that was at the centre doing a shore dive.
I remember it because my wife said its a long way back from the end of the jetty across the beach to the centre to fetch the oxygen. I said well lets just hope no-one needs it. The mentioning of the first aid actually worried us at the time and we both said why are they telling us where it is shouldn't they be the ones looking after it? Very naïve I know. From now on I will start asking questions and paying more attention.
I maybe don't listen enough as I try not to worry or stress about these things as it could put me off diving but from now on if I don't hear anything mentioned at the briefing then I am going to ask.
Reading this has changed my attitude somewhat in the fact that I have always thought 'I am the customer and they know what they are doing. They will look after me if there is a problem'. Not any more.
On an aside note; we are just holiday divers but bought all our own kit to make sure it is serviced properly. I had a problem in the past when my pressure gauge flooded after servicing. Discussing this with a guide last time out he said 'I don't have my regs serviced for this very reason. The number of guests we have that have just had their regs serviced but then have problems you wouldn't believe. Leave them alone if they are working correctly.' I found a bit of a scary statement.