Undeserved hit

[DivingDoc]

leadweight once bubbled...


The explanation is easy. The liveaboard divers play it safe. The much more interesting question is why is the accident rate so high for the cold water wreck divers.

In what ways do they play it safe? I've never been on a livaboard.

 

[vicky]

http://www.e-nekton.com/feature-1.html

I was just wondering if one can take the numbers of treatments reported by recompression-chamber operators as a real representative number of DCS risk in scubadiving.
For example, the Recompression Chamber in Eilat is operated by a private company. They get paid quite a lot of $$$ by insurance companies for each treatment they do. If someone gets to the hospital for any reason and mentions that he was doing some scubadiving he is sent to the recompression chamber, even if the poor guy was just dehydrated or whatever- he gets a treatment in DCS chamber and his insurance pays for it. These cases are reported to authorities as DCS treatments, but most of the times the diagnosis was dehydration, sunstroke, severe tiredness (people driving all night and then go diving all day and in the evening they feel bad and go to the hospital) and so on. I don't know if it the same in other countries, but I wouldn't be surprised if this is the case.

 

[fins wake]

For the liveaboard divers there were no cases of DCS in about 4000 dives.

This could well be true for liveaboard divers in the United States and Caribbean. For liveaboard diving in other areas of the world this is not necessarily true.

The Red Sea hyperbaric facility at El Gouna, Egypt, for example treats about 7 divers a week on average. By far the majority of these are liveaboard divers, according to local dive industry sources.

It could well be that the dive profiles for liveaboard divers in the US/Caribbean significantly deviate from those common in the Red Sea. I've heard anecdotes of Red Sea liveaboard divers treated for DCS who've had up to 6-7 dives a day for a couple of days before the onset of symptoms. Deep diving - although technically banned by Egyptian authorities for recreational divers - is also very common on some safari boats in the region.

 

[Dr Deco]

Dear Readers:

Live-aboards and DCS - - - =-)

I find this a very fascinating topic and, I will be very interested in following the course of events in the future.

Dr Deco :doctor:

Readers, please note the next class in Decompression Physiology :grad:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[DivingDoc]

Dr Deco once bubbled...
Dear Readers:

Live-aboards and DCS - - - =-)

I find this a very fascinating topic and, I will be very interested in following the course of events in the future.

Dr Deco :doctor:

I have never been on a liveaboard, but if it's in any way similar to diving in Cozumel, there is much less exercise involved than in, say NJ coast or even NC coast wreck diving.

In Coz, at least where we were diving, all you have to do in the morning is go down to the dive operation, get your dive bag out of your locker, and plop it about 20 feet away. It is picked up and taken to the boat for you. True, you have to waddle down the boat to your big step entry with all your gear on, but then when you come back to the boat, you inflate your BC and take it off and the crew member lifts it out of the water for you and even attaches your BC and reg to your next tank. Then you hand up your fins and all you have to lift when you climb the ladder is yourself. When you leave the boat, all the dive bags are loaded onto a cart and brought back to the rinse tank for you. All you have to do is rinse out your stuff and put it back into your bag and back into your locker. On top of all this, all the diving is drift diving, so you hardly have to kick, even during the dive.

In contrast, on a NC coast wreck dive, not only are you likely to be wearing more equipment (maybe a 100 cubic foot tank or a steel 120 plus a pony bottle) , but no one helps you get you or your stuff back on the boat. In fact, they even have a fin ladder, so you can climb up in your fins. Add higher waves to this and current, and you are doing a whole heck of a lot more exercise. On the NJ coast, you add cold water (NC wrecks are in the Gulf Stream), requiring thicker wetsuits or a dry suit, which in turn requires more weight, therefore more huffing and puffing to get in and out of the boat. Also, some of the NJ wreck divers do tech diving and carry a couple of extra tanks with them as well.

ET

 

[fins wake]

Yet there are only some 30-50 cases of DCI (DCS and AGE) treated every year in all the Swedish hyperbaric chambers. This has been constant for many years. This despite a lot of people regularly doing 30-40 metre cold-water wreck dives, some with very heavy equipment indeed.

I usually dive steel twin-15:s (uuuurgh!) if I'm on OC. And there certainly is no help whatsoever from the DM:s, in fact most of them stay on land as surface back-up. There is a lot of lugging heavy equipment around.

None of this means that cold-water wreck diving isn't more conductive to DCI than tropical liveaboard diving in the US. It may well be. In fact, because DCI cases in Sweden are uniformly and completely treated on tax-payers' money, and money for the chambers is scarce, it may well be that some lesser symptoms of DCS (e.g. minor joints-only DCS) goes untreated in Sweden, whereas it would be treated in the US (or elsewhere) using DAN insurance or similar.

Or it may be that the general ultra-macho dive environment (sadly) in Sweden means less divers seek treatment for what they perceive as 'minor ailments' but which might well be less serious forms of DCS (an AGE is usually swift and painful, and is thus more likely treated anyway). Or perhaps Swedish divers are well-trained and highly disciplined and simply dive safer, ascending slowly, staying well within NDL limits or following conservative deco procedures?

I don't know.

Certainly in the UK things are very different. Again, we're talking cold-water wreck diving to a large extent. We're also talking a rising incidence of DCI, contrary to world figures, and a very high fatality rate.

All in all, I have my own opinions as to why this is so, but this post is already long enough.

 

[DivingDoc]

dtdiver once bubbled...
i wonder if the symptoms could be temporally related to his vomiting

the valsalva with a pfo (or opened a non-patent pfo) could have shunted venous bubbles

thusly resulting in his acute symptoms assoc with vomiting and diarrhea

dt

His vomiting started at 4AM. Diarrhea a bit later. First DCS symptom was left arm tingling at approx. 9AM. He is not known to have a PFO. He was[/] born with a congenital cataract and ultimately had to have one eye removed and replaced with a prosthesis. He had no pain or symptoms referable to the area around the prosthesis, which is very well vascularlized.

 

[pufferfish]

Hi DD, A very interesting story and good to hear the SIL is ok. Dr. Deco briefly touched on the possible diagnosis of a toxin reaction. Given the temporal delay and the fact he presented with nausea and vomiting followed by diarrhea this does not sound like DCS. I believe you also said he had chills and fever.

No one has considered the great mimicker of DCS, ciguatera poisoning. Very common in the Carribean and possibly endemic in Cozumel, I know it is in Roatan. The question then is did your SIL eat grouper, snapper, jack, or barracuda that evening before or after the night dive? Strickland's Tropical Disease say symptoms start 4 to 30 hours after ingestion of the toxic fish and Harrison's says symptoms start typically within 1 to 3 hours, most commonly less than 12 hours but up to 24 hours.

Harrison's (pg2620) lists nausea, vomiting, chills, diarrhea, dyspnea, and many neurological signs which would mimick DCS. Strickland says paralysis has been reported.

Another less likely diagnosis would be paralytic shellfish poisoning which results from the ingestion of 'poisoned' shellfish like clams, mussels, scallops, and oysters. Many of the same symptoms as ciguatera including flaccid paralysis but it seems the onset of symptoms is faster as in minutes to hours after ingesting the toxic shellfish.

Anyhow just a thought and is irrelevant if the SIL didn't eat any fresh fish or shellfish in the preceding twelve hours.
Here is an article from Oct/02 Rodales
Ciguatera vs DCS

So info from his dietary log please!

 

[pufferfish]

Of course we assume he did not eat any pufferfish either. We generally are peaceful but if eaten our tetraodon toxin can turn the lights out permanently. Don't eat puffers or porcupine fish
Puffer

 

[DivingDoc]

Good thought. But I think he had a breakfast bar for breakfast, then chicken encheladas (sp?) verde (which I think was the suspect meal), and a Balance Bar, bought in the States, for dinner before the night dive.

We all ate at the same restaurant for lunch, but no one else had the encheladas. One of the other members of our larger group said that he had eaten the encheladas every day from that restaurant, which was next to the dive op at the hotel. Not sure, however, if he had the verde sauce. If the verde sauce was the same green sauce they served with their quesedias (sp?), then I had that on most days too. I suppose it could have been the chicken.

Since his stools and vomit seemed to have alot of bile in them and were green, the Mexican physician at the Hyperbaric Chamber felt he had a bacterial infection. And, indeed, the fever responded within a day to Cipro, though he had milder residual diarrhea for a week. This would suggest Salmonella or Shigella or even enterotoxigenic E. Coli.

Ciguatera toxicosis, to my memory, is also associated with a bright red sunburn-like rash as well, but I'd have to look that up to see if I'm remembering right (out of my field). John did not have a rash.

ET

pufferfish once bubbled...
Hi DD, A very interesting story and good to hear the SIL is ok. Dr. Deco briefly touched on the possible diagnosis of a toxin reaction. Given the temporal delay and the fact he presented with nausea and vomiting followed by diarrhea this does not sound like DCS. I believe you also said he had chills and fever.

No one has considered the great mimicker of DCS, ciguatera poisoning. Very common in the Carribean and possibly endemic in Cozumel, I know it is in Roatan. The question then is did your SIL eat grouper, snapper, jack, or barracuda that evening before or after the night dive? Strickland's Tropical Disease say symptoms start 4 to 30 hours after ingestion of the toxic fish and Harrisons says symptoms start typically within 1 to 3 hours, most commonly less than 12 hours but up to 24 hours.

Harrisons (pg2620) lists nausea, vomiting, chills, diarrhea, dyspnea, and many neurological signs which would mimick DCS. Strickland says paralysis has been reported.

Another less likely diagnosis would be paralytic shellfish poisoning which results from the ingestion of 'poisoned' shellfish like clams, mussels, scallops, and oysters. Many of the same symptoms as ciguatera including flaccid paralysis but it seems the onset of symptoms is faster as in minutes to hours after ingesting the toxic shellfish.

Anyhow just a thought and is irrelevant if the SIL didn't eat any fresh fish or shellfish in the preceding twelve hours.
Here is an article from Oct/02 Rodales
Ciguatera vs DCS

So info from his dietary log please!