DCS Incident - Salient lessons to be learned

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Diving Dubai

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I’ve been toying whether to put this is the accidents and incidents thread, or in the basic forum as it does have some salient lessons. MOD’s please use your discretion and pt where you feel it is best served

Firstly this didn't’ happen to me, but I was there. Secondly names have been changed to protect the innocent. Sorry it’s so long but it’s better that the complete picture is told

Background

The Story starts in Aug with a trip to a Mediterranean Island. We (at the time soon to be, but now wife) were scheduled to dive a well-known wreck. Prior to this the dive op wanted to conduct a check dive the day before. Given the wreck dive was to be around 30m max depth 42m we were happy to go and get wet.

The check dives were from the shore, and no deeper than 11m so as not to impact too much on the next day’s diving. We were collected and met up with a guy called Fred. Whilst chatting we found out he was 50 a professional physiotherapist and a DM with approx. 500 dives. He’d started his instructor training but stopped as he’d decided that he didn’t’ want to teach just to dive. Unlike us who dive most weeks Fred was a vacation diver and hadn’t dived for 4 months. this was teh first leg of a months vacation travelling all over the Med diving

So we geared up and had a long walk to the entry point through hotel grounds perhaps 100 – 150m The temperature was about 30/31C we were okay (The temp in Dubai where we live is 40+ in the Summer so we’re used to it) however we all partook of the beach shower to cool down before going heading to the water.
Dive 1 completed no probs, we hoofed our kit to the car. We didn’t care for a second dive as there was zero fish life and it wasn’t’ very challenging, but Fred was eager so we went in again after a usual surface stop.

Incident

The next day was an early start (06:30) for the 90min drive to the harbour. We all napped en-route. Wifey and I had shared a bottle of wine the previous evening. Fred had gone for a few beers but seemed okay – he certainly didn’t’ smell of beer. We arrived at the boat – dumped the kit and went for coffee and bacon butties at a local café before heading to the boat.
Soon after we departed for the 10 min ride to the site, we kitted up having already had a dive brief by our guide. Fred was buddied up with Jack a BSAC instructor and expedition leader in the UK armed forces.

The dive was normal, a slow descent to the hull at 18m then down to the props at 25 followed by a slow partial circuit of the wreck, slow ascent, stop at 6m and back on the boat with a dive time of around 40min – we were all on Air as Nitrox was by special request. The usual post dive chat went on, Fred was a bit withdrawn claiming he hadn't got into the groove on that dive but hoped the next dive would be better (for him)


About half way through the surface interval Fred mentioned he thought he’d trapped a nerve in his arm getting back on board (remember he’s a professional physiotherapist) but maybe 15mins later he though it had got worse with some tingling in his finger tip and was going to sit out the next dive. Wifey suggested he have a blast of O2 and a lie down in case that improved things… It did the tingling went. At that point he was taken off the boat and sent to the diving medical centre wit our guide)
We had a Fab second dive with Jack leading and this time did some penetration. The guide collected us and informed us that the hospital had done tests, decided that Fred did have a DCS and put him in the chamber.

Summary

Fred spent 5hrs in the chamber and overnight in a private hospital.
His profile was shallower than ours – we were at 29m he at 24, he also had a shorter dive and didn’t exceed his NDL. There was nothing on his computer which would indicate a reason for this DCS
The day before and on the boat no-one saw Fred drink water and hydrate – not to say he didn't’, just no-one saw him

Afterthought.
Fred had got his dive insurance via his credit card travel insurance, unfortunately the small print was that he was only covered to 18m (even though he was a DM thus certified to 30) and he was presented with a $26,000 USD bill!

Lessons.
Re-hydrate and Stay hydrated

Check your insurance and DON’T DIVE BEYOND YOUR CERTIFICATION DEPTH as most insurers won’t cover you

Possibly the saddest part of this tale is that Fred decided that he would probably hang up his fins and give up diving altogether. Maybe he changed his mind - I hope so

Those with medical experience make add further light to the incident and I’ll answer any questions I can
 
Thanks for sharing. Some observations.

1. In decompression diving, it's noted that all dives are decompression dives. Even those staying within NDL limits. An oft cited example is a DM/instructor doing successive controlled emergency ascent drills with students in the shallows but now and then succumbing to DCS.

2. Decompression models are principally physics models (e.g., bubble dynamics), meaning the physiology component is still very weak. The latter, in part, requires advances in basic science since our understanding of narcosis, pain and analgesia is still evolving (we know a lot but we also know that a lot is missing).

3. The physiology component is reflected in empirical studies conducted with humans by various organizations including the US Navy. That's very valuable information which shows out of N divers how many develop DCS symptoms when subject to condition C. However, as noted, in many instances these divers are very fit sailors so do not necessarily reflect the general recreational diving public. There are overall stats on what percentage of divers may develop DCS even if they obey NDL limits (for no specifically identified causality). Dehydration (if he had one too many beers) may have been a factor but it's possible that there were no obvious factors that would help explain the onset of DCS.

BTW, Kudos to your wife for suggesting O2 inspiration when symptoms set in. Whether she's rescue trained or not, may have made a significant difference.
 
Thanks for sharing. Some observations.


BTW, Kudos to your wife for suggesting O2 inspiration when symptoms set in. Whether she's rescue trained or not, may have made a significant difference.
No she's not rescue trained (we're doing that in a couple of weeks) Just one of those titbits of information you pick up in a club full of highly experienced divers .. Clearly not by me until this incident though!
 
There is not a lot of evidence out there that shows that dehydration has a significant effect on DCS rates. You and you wife drank wine, a more dehydrating beverage, the night before and did not get bent why not conclude that dehydration has little effect? It might be more helpful to focus on average depth and time, or ascent rates, or time spent at stops, all factors that have been demonstrated to make a difference.

I don’t know who the insurer, or who certification agency was but in the past the OW limits were 130 fsw/40 msw with a recommendation not to go that deep without further experience. It appears the standards have evolved but as far as I know depth limits less than 40 meters are recommendations only and as such you would not be diving beyond your certification depth. But...that may depend on the certification and insurance agency so reading the fine print might be a lesson learned.

Early use of oxygen was smart. Also another lesson learned might be that nitrox is really cheap, even if it is a special order, compared to chamber bills.
 
So to summarize... He stayed up late, went out for a couple drinks, got up early, then drank coffee instead of hydrating. There's three risk factors right there: not enough rest, combined with alcohol and dehydration. Mystery solved!

That's exactly how I got bent about 10 years ago. Stayed up until almost midnight helping mix tanks with Trimix, while having a beer of course. Then got up early the next day for the dive. That next morning, I was dragging a little so I decided to have a coke to perk up instead of hydrating. Then did a dive to ~220ft with a group of divers. Mysteriously, I was the only one that got hit. <Sarcasm> Everyone said it was an undeserved hit, but with a little introspection I soon realized there's no such thing. I had the same three risk factors, but also followed those with a deep and strenuous dive. So that's probably five risk factors on one dive. The chamber doctor seemed to think it had something to do with the cold at depth, but I was wearing a drysuit. However, we did have some thermoclines that year and I still got cold on the dive. So there's always a reason, you just have to reflect a little. Other people can't do this for you because they weren't in your shoes. They don't know how many beers you had, how long you stayed up, or whether you slept well, whether you exerted yourself on the dive, etc...

Bottom Line: there's no such thing as an undeserved hit. It only means someone hasn't bothered to exert enough introspection to find the answer.
 
The dive was normal, a slow descent to the hull at 18m then down to the props at 25 followed by a slow partial circuit of the wreck, slow ascent, stop at 6m and back on the boat with a dive time of around 40min – we were all on Air as Nitrox was by special request. The usual post dive chat went on, Fred was a bit withdrawn claiming he hadn't got into the groove on that dive but hoped the next dive would be better (for him)

While it's nice to share the story, I think you missed the point.

You did a 25m dive for 40 minutes on air. vPlanner shows this as requiring almost 20 minutes of deco, which you didn't do.

The surprising part isn't that Fred got bent, but that nobody else was bent along with him.

Also, I can't imagine relying on my credit card for SCUBA insurance. That's what DAN is for. Buy a plan without a depth limit and it won't be a problem.

flots.
 
Then got up early the next day for the dive. That next morning, I was dragging a little so I decided to have a coke to perk up instead of hydrating.

Actually, you did hydrate. Just because the caffeine in a soda can lead to some diuresis does not mean that the net effect of water gain from soda - diuresis from caffeine = a net water loss. I imagine the same volume of water would be more hydrating, but then again, I drink a lot more soda than water.

Richard.
 
the OP stated maximum depths of 29 and 24 metres with a time of 40 minutes. they didn't spend 40 minutes at their maximum depth.

vPlanner calls for a bunch of deco, and assumes a square profile.

If the victim's computer really said this was a no-deco dive (I'm not all that certain about that aspect), it sounds like a really good reason to not ride computers on deep dives.

flots.
 
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