another unexplained DCI hit..

[MoonWrasse]

ok, I think I will throw my 2 cents worth in. As a recompression chamber nurse, I find that may divers that suffer from DCI don't understand why they do. They claim that according to the computer that they never went into a decompression dive and that the did the appropriate surface intervals and hang times.

My theory (and it is only that) is that when computers are programmed, they are so according to the Navy Dive Tables. These tables were initially devised for extremely fit, low body fat, young divers. There are a lot of factors that these tables to not take into consideration. One is an age of a recreational diver, the other is the weight or the diver's metabolism, just to name a few.

A few weeks ago I had a diver who had a similar accident with CNS and brain DCS. He stated that he couldn't understand how he got it as he followed his computer and it never told him that he was in any danger.

This gentlemen, who was a very experienced diver (first time DCS), and a great guy did have some factors that that COULD have attributed to his DCS.

First he was overweight, with a large round abdomen, where most of his body fat was concentrated. Nitrogen LOVES to hide out in body fat, and normally takes a longer time to release. This gentlemen was doing 4-5 dives a day consecutively for about 5-7 days. He was also over the age of 55.

I personally think that even though his computer and dive tables told him he would not encounter DCS, he had a large amount of factors that prevent the nitrogen from actually disapating. It built up in his fat cells, his metabolism, due to his age did not work productively, therefore, I feel it was a slow buildup, giving him the "hit" in 1 dive.

Has any research been done on this? Also, he did not look, nor did he express any other forms of daily or even regular exercise other than diving. Would love to hear more on the subject.

I agree and disagree.

First, as I recall, there were more recent studies aimed at the recreational diver population in the 90's, which the dive computers may utilize instead of the navy data.
However, I'd say based on looking at some accident reports such as this one, that diving strictly by watching the computer and not considering the other factors (age, fat, dehydration, SI exercise, booze, etc) which are published, people get into trouble.

One is(hopefuly) trained not to dive the computer.

Just my 2 cents.

 

[pilot fish]

ok, I think I will throw my 2 cents worth in. As a recompression chamber nurse, I find that may divers that suffer from DCI don't understand why they do. They claim that according to the computer that they never went into a decompression dive and that the did the appropriate surface intervals and hang times.

My theory (and it is only that) is that when computers are programmed, they are so according to the Navy Dive Tables. These tables were initially devised for extremely fit, low body fat, young divers. There are a lot of factors that these tables to not take into consideration. One is an age of a recreational diver, the other is the weight or the diver's metabolism, just to name a few.

A few weeks ago I had a diver who had a similar accident with CNS and brain DCS. He stated that he couldn't understand how he got it as he followed his computer and it never told him that he was in any danger.

This gentlemen, who was a very experienced diver (first time DCS), and a great guy did have some factors that that COULD have attributed to his DCS.

First he was overweight, with a large round abdomen, where most of his body fat was concentrated. Nitrogen LOVES to hide out in body fat, and normally takes a longer time to release. This gentlemen was doing 4-5 dives a day consecutively for about 5-7 days. He was also over the age of 55.

I personally think that even though his computer and dive tables told him he would not encounter DCS, he had a large amount of factors that prevent the nitrogen from actually disapating. It built up in his fat cells, his metabolism, due to his age did not work productively, therefore, I feel it was a slow buildup, giving him the "hit" in 1 dive.

Has any research been done on this? Also, he did not look, nor did he express any other forms of daily or even regular exercise other than diving. Would love to hear more on the subject.

What you say makes a lot of sense and being a recompression chamber nurse means you know of what you speak. I wonder if that diver had taken a day off in the middle of his vacation, as I see some divers do, would have prevented that?

 

[pilot fish]

I agree and disagree.

First, as I recall, there were more recent studies aimed at the recreational diver population in the 90's, which the dive computers may utilize instead of the navy data.
However, I'd say based on looking at some accident reports such as this one, that diving strictly by watching the computer and not considering the other factors (age, fat, dehydration, SI exercise, booze, etc) which are published, people get into trouble.

One is(hopefuly) trained not to dive the computer.

Just my 2 cents.

Have those new studies prompted new tables? I confess to divng my two puters but I do add longer SS and half depth stops. I would also add a day off in a 7 day dive trip.

Your two cents is worth a lot more

 

[Bob3]

Please do not post links/articles from Cyber Diver; they're notorious plagiarizers.
They're also spammers that use spam botted email addresses as "subscribers" to boost their numbers to give to potential advertisers.

 

[Halthron]

Please do not post links/articles from Cyber Diver; they're notorious plagiarizers.
They're also spammers that use spam botted email addresses as "subscribers" to boost their numbers to give to potential advertisers.

And how does that pertain to the information in the article? Do you have knowledge that the information in the article was incorrect? I'm concerned about the information and how truthful it is, not where it came from.

 

[paolov]

so it is good then to have a weekday job and just go diving aroound 3 days a week.

nice sharing fro the overweight thing. especially here , BUFFET MEALS !!!!

 

[dvrliz1]

I have to tell you, as most of you know we also own a dive resort and the MAJORITY of our guests tell us they TOTALLY rely on their computers. These are usually recreational divers with either open water or advanced open water certs. I think that it needs to be stressed that during training that the weight, booze, age thing needs to be emphasised during training and that divers SHOULD NOT rely on their computers, but should take in to consideration all the other things we are talking about. I think it would be a HUGE undertaking, but I think that dive tables should be revised for teaching to reflect the AVERAGE recreational diver. Then they should have Recreational diver computers based on the new tables. I think most rec divers would be surprised at how dangerous sometimes they may come to getting the "bends"

Liz

 

[DiveGolfSki]

I have to tell you, as most of you know we also own a dive resort and the MAJORITY of our guests tell us they TOTALLY rely on their computers. These are usually recreational divers with either open water or advanced open water certs. I think that it needs to be stressed that during training that the weight, booze, age thing needs to be emphasised during training and that divers SHOULD NOT rely on their computers, but should take in to consideration all the other things we are talking about. I think it would be a HUGE undertaking, but I think that dive tables should be revised for teaching to reflect the AVERAGE recreational diver. Then they should have Recreational diver computers based on the new tables. I think most rec divers would be surprised at how dangerous sometimes they may come to getting the "bends"

Liz

Back in the days when DC's where not around (unless you count ScubaPro's non-electronic version), tables were used extensively specifically the U.S. Dive tables which where derived by experiments involving fit, trained U.S. Navy divers (not to go into details). Recreational divers not nearly as fit as those divers used those tables and may have pushed the limits slightly ... hence, the same factors you mentioned come into play whether a computer or a table is used.

Relying solely one versus the other isn't necessarily advisable either. Liz, I think your point that other factors (fitness, excersise, etc.) all come into play in DCI. Tables and DC's try to achieve a "best fit" but building additional conversatism individually is probably the better choice. Some DC's can be adjusted to build in additional conservatism and tables times can be manually tweaked on the conservative side.

The only problem is bottom times will be reduced and, possibly, the number of dives. The temptation to be more aggressive can be too much for some.