DCI: What could have triggered it?

Yann A. · 30th December 2006, 01:19

Dear All,

This is a non-rebreather diving incident but as a member of this forum I thought I ask the question here on Rebreather World as it has the highest concentration of knowledgeable people on the net. Here is what happened:
No excessive drinking (only 2 beers during dinner the previous day) or drug usage before the dives or days prior to the dives, no previous condition, healthy diver 36 years old The dives went without ay incident, the profiles were smooth (no ups and downs) and well within the No-deco limits. 1st dive 26.5m for 46minutes, surface interval of 1h14, 2nd dive 26.7m for 55minutes, surface interval 1h35, 3rd dive 21m for 57minutes. Theses dive times all include a minimum 3minutes safety stop and at no time during the dive did the diver went into deco.
15h00, 30 minutes after the last dive of the day, the diver started to feel very tired and weak. No oxygen was available so he’s been given some water and asked to rest. 15h45, the diver complained of feeling loss in the fingers and some “blue-black” marble patches started to be seen on his upper body (chest, back and shoulders) so we started the 4h drive to the chamber. During the trip the diver developed severe pain in the legs that increased as we were driving up to a maximum of 600 to 800m above sea level (no choice as it was the shortest road to the hyperbaric facility.
By the time we reached the chamber at 19h (4h after the last dive) the pain had gone and the skin patches were no longer as blue-black but disappearing slowly. Although we did call the hyperbaric physician on call and she told us the chamber was ready, nothing had been done and we were up to a 2h wait going thru ER process of general examination and chest X rays, till she finally arrived at the hospital. At 22h, the doctor decided not to treat the diver who was said to have a body temperature too high (37 degrees C) and she decided to place him under observation for the night and run a USN table 6 treatment the next morning. No oxygen was given to the diver (except for 30min in the ER when we requested for it). The diver felt only a bit dizzy the next morning but was treated (one run under USN Table 6) and asked not to fly for the next 72h nor dive for 1 month. The diver is now fine.

The purpose of this mail is to try to understand what may have gone wrong to justify this DCI only and not on the way the emergency has been handled we know what the loop holes were and will use a different dive operator the next time.

Thanks for your help to understand what can have triggered this DCI.

Yann.

cramerdn · 30th December 2006, 01:49

From what you wrote your friend got bent by diving beyond the No Deco limits without doing any deco.

The first dive of 26.7 m for 45 minutes is well beyond the Navy tables 30 minute no-deco limit for 28 m. If you use a Padi table its only 20 minutes for no-deco, but you have to use the 30 m numbers.

When I plugged the first dive into V planner (on nominal conservatism) I got

Decend to 26.5m (1) Air 15m/min descent.
Level 26.5m 43:14 (45) Air 0.76 ppO2, 27m ead
Ascend to 9m (46) Air -9m/min ascent.
Stop at 9m 3:03 (50) Air 0.40 ppO2, 9m ead
Stop at 6m 7:00 (57) Air 0.34 ppO2, 6m ead
Stop at 3m 13:00 (70) Air 0.27 ppO2, 3m ead
Surface (70) Air -9m/min ascent.

So V planner says you owed about 23 minutes of deco

If your dives were not all at the depth you listed then you will have to use the depths and times to build a profile to see if you exceeded any limits.

Was there a computer involved?

When you say The dives were "well within the No-deco limits" what limits were you using?

Yann A. · 30th December 2006, 02:38

Hi cramerdn,

The depths mentioned are of course the Max depths… The diver did a series of 3 very classic rec dives and didn’t get into deco at any time during any of the dives… (as mentioned in my post).
Maybe should have I precised that the diver was using an Aladin Sport dive computer.
Thanks for your input but the cause is somewhere else…

Yann.

Yann A. · 30th December 2006, 03:01

I'd love to post the profiles but the diver doesn't have the data trax to get the profiles out. This diver is very safety conscious and never gets closer than 10min from the deco limits… To my knowledge, the dives profiles are clear of any suspicion. That’s what made me ask the question, as I had never imagined dehydration alone could trigger DCI. The dives were really easy, no current, warm clear waters... Ideal conditions really.

abowie · 30th December 2006, 03:27

Bad luck.

DCI is essentially a statistical entity. Just because you "dive within the NDL" doesn't mean that you can't get bent, just that it is unlikely.

To be honest that does look like a moderately provocative series of dives with (from a recreational perspective) reasonably deep maximum depths, shortish surface intervals and dives around the hour mark. While you friend is no doubt disapointed to have got bent, the only way to be absolutely certain of not getting bent is to never go diving.

I would ensure he is reviewed by a competent hyperbaric physician in the near future to talk through the implications of his bend.

cramerdn · 30th December 2006, 05:04

Quote: (Originally Posted by Yann A.)

Hi cramerdn,

The depths mentioned are of course the Max depths…

Oh course how silly of me to read what you wrote instead of knowing that

Anyway, Has he been checked for Patent Foramen Ovale (PFO)? Info here... Patent Foramen Ovale

As far as the beers? My rule is that I don't drink at all untill the last dive of the last day of my trip. (or sometimes if I have a one or two day full break and the San Miguels are really cheap

) But two beers the night before seams pretty conservative.

dteubner · 30th December 2006, 06:03

Quote: (Originally Posted by abowie)

Bad luck.

DCI is essentially a statistical entity. Just because you "dive within the NDL" doesn't mean that you can't get bent, just that it is unlikely.

To be honest that does look like a moderately provocative series of dives with (from a recreational perspective) reasonably deep maximum depths, shortish surface intervals and dives around the hour mark. While you friend is no doubt disapointed to have got bent, the only way to be absolutely certain of not getting bent is to never go diving.

I would ensure he is reviewed by a competent hyperbaric physician in the near future to talk through the implications of his bend.

Absolutely.

When I do recreational diving medicals I tell the people that, if they decide to go diving, there is an inevitable risk of DCI. You can do things to decrease the risk but you cannot eliminate it.

Whenever people post things like this there is allways dehydration, PFO etc etc etc. Maybe sometimes these are implicated but in the vast majority of cases the answer to "Why did I get bent?" is "Because you went diving".

Dave T

Gobfish1 · 30th December 2006, 07:17

surface interval 1h35

maybe you want to do a bit more SI , time between dives , your pushing bottom times by the use of depth change,s on the dives just to stay in side the no deco times of your computers , ha we all do it ,

You spent a lot of time in the water with 3 dives ,
Think its some bad luck, and maybe some bad thinking

Average depth of 25m and a average 52mins for all 3 dives
Average si was 85mis think you need to revaluate your dive times and si

Glad to see no harm came of it

ps your average dive
,
dive to 25m for 52:00 (53) on Air, PPO2 0.731, END 25
Deep Stop at 18m for 2:00 (56) on Air, PPO2 0.585, END 18
Deep Stop at 12m for 2:00 (58) on Air, PPO2 0.460, END 12
Norm Stop at 6m for 33:00 (92) on Air, PPO2 0.335, END 6

TOTAL DECO TIME: 37 minutes.
DIVE RUN TIME: 92 minutes.

average square profile dive / 3 dives = 12.3 mins not just a 3 min stop at 3m

this is just one way to look at it from out side the box

ps
surface interval should be made to suite the diving, NOT to suite the dive boat DM so he can get back to dive shop by 4pm for a drink with his M8s

Yann A. · 30th December 2006, 07:19

cramerdn,

Oh course how silly of me to read what you wrote instead of knowing that

I thought that when I worte: "the profiles were... well within the No-deco limits", and "...at no time during the dive did the diver went into deco." It would have been made obvious and clear enough that the diver hadn't spent his total time at depth but only "visited that depth for a short time... But then maybe not for everyone...

Andrew, Dave

Agree with you and an examination by a proper hyperbaric physician is planned. PFO seems vrey unlikely though, as the diver get complete medical check every 6 months for work.

Thanks for your thoughts.

abowie · 30th December 2006, 07:34

Quote: (Originally Posted by Yann A.)

PFO seems vrey unlikely though, as the diver get complete medical check every 6 months for work.

There's up to a 30% chance that the diver has a "probe patent" PFO because that's the incidence of PFO in the general population. So statistically either you, I or Dave T has one.

It's most unlikely that a small one would be detected during royutine physical examination unless he actualy had the specific test for it.

Whether it's worth looking for a PFO (not, in my view), and what it means if anything if he does have one (quite unclear in my view) is entirely something else. That's why I think he should speak to a suitably qualified hyperbaric doctor who can give him the facts so that he can make some sensible decisions about further investigations he might like to have, and further diving.

30th December 2006, 01:19	#1 (permalink)
Yann A. New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Feb 2005 Location: Indonesia Posts: 49	DCI: What could have triggered it? Dear All, This is a non-rebreather diving incident but as a member of this forum I thought I ask the question here on Rebreather World as it has the highest concentration of knowledgeable people on the net. Here is what happened: No excessive drinking (only 2 beers during dinner the previous day) or drug usage before the dives or days prior to the dives, no previous condition, healthy diver 36 years old The dives went without ay incident, the profiles were smooth (no ups and downs) and well within the No-deco limits. 1st dive 26.5m for 46minutes, surface interval of 1h14, 2nd dive 26.7m for 55minutes, surface interval 1h35, 3rd dive 21m for 57minutes. Theses dive times all include a minimum 3minutes safety stop and at no time during the dive did the diver went into deco. 15h00, 30 minutes after the last dive of the day, the diver started to feel very tired and weak. No oxygen was available so he’s been given some water and asked to rest. 15h45, the diver complained of feeling loss in the fingers and some “blue-black” marble patches started to be seen on his upper body (chest, back and shoulders) so we started the 4h drive to the chamber. During the trip the diver developed severe pain in the legs that increased as we were driving up to a maximum of 600 to 800m above sea level (no choice as it was the shortest road to the hyperbaric facility. By the time we reached the chamber at 19h (4h after the last dive) the pain had gone and the skin patches were no longer as blue-black but disappearing slowly. Although we did call the hyperbaric physician on call and she told us the chamber was ready, nothing had been done and we were up to a 2h wait going thru ER process of general examination and chest X rays, till she finally arrived at the hospital. At 22h, the doctor decided not to treat the diver who was said to have a body temperature too high (37 degrees C) and she decided to place him under observation for the night and run a USN table 6 treatment the next morning. No oxygen was given to the diver (except for 30min in the ER when we requested for it). The diver felt only a bit dizzy the next morning but was treated (one run under USN Table 6) and asked not to fly for the next 72h nor dive for 1 month. The diver is now fine. The purpose of this mail is to try to understand what may have gone wrong to justify this DCI only and not on the way the emergency has been handled we know what the loop holes were and will use a different dive operator the next time. Thanks for your help to understand what can have triggered this DCI. Yann.
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30th December 2006, 01:49	#2 (permalink)
cramerdn Obey my dog! Current Rebreather/s: Evolution Dolphin Other Rebreather/s: Dolphin Join Date: Dec 2006 Location: Townsville QLD Posts: 626	Re: DCI: What could have triggered it? From what you wrote your friend got bent by diving beyond the No Deco limits without doing any deco. The first dive of 26.7 m for 45 minutes is well beyond the Navy tables 30 minute no-deco limit for 28 m. If you use a Padi table its only 20 minutes for no-deco, but you have to use the 30 m numbers. When I plugged the first dive into V planner (on nominal conservatism) I got Decend to 26.5m (1) Air 15m/min descent. Level 26.5m 43:14 (45) Air 0.76 ppO2, 27m ead Ascend to 9m (46) Air -9m/min ascent. Stop at 9m 3:03 (50) Air 0.40 ppO2, 9m ead Stop at 6m 7:00 (57) Air 0.34 ppO2, 6m ead Stop at 3m 13:00 (70) Air 0.27 ppO2, 3m ead Surface (70) Air -9m/min ascent. So V planner says you owed about 23 minutes of deco If your dives were not all at the depth you listed then you will have to use the depths and times to build a profile to see if you exceeded any limits. Was there a computer involved? When you say The dives were "well within the No-deco limits" what limits were you using?
(Online)

30th December 2006, 02:38	#3 (permalink)
Yann A. New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Feb 2005 Location: Indonesia Posts: 49	Re: DCI: What could have triggered it? Hi cramerdn, The depths mentioned are of course the Max depths… The diver did a series of 3 very classic rec dives and didn’t get into deco at any time during any of the dives… (as mentioned in my post). Maybe should have I precised that the diver was using an Aladin Sport dive computer. Thanks for your input but the cause is somewhere else… Yann. Last edited by Yann A. : 30th December 2006 at 02:45.
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30th December 2006, 03:01	#4 (permalink)
Yann A. New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Feb 2005 Location: Indonesia Posts: 49	Re: DCI: What could have triggered it? I'd love to post the profiles but the diver doesn't have the data trax to get the profiles out. This diver is very safety conscious and never gets closer than 10min from the deco limits… To my knowledge, the dives profiles are clear of any suspicion. That’s what made me ask the question, as I had never imagined dehydration alone could trigger DCI. The dives were really easy, no current, warm clear waters... Ideal conditions really.
(Offline)

30th December 2006, 03:27	#5 (permalink)
abowie Fighting Girl Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: May 2005 Location: Land of Oz Posts: 574	Re: DCI: What could have triggered it? Bad luck. DCI is essentially a statistical entity. Just because you "dive within the NDL" doesn't mean that you can't get bent, just that it is unlikely. To be honest that does look like a moderately provocative series of dives with (from a recreational perspective) reasonably deep maximum depths, shortish surface intervals and dives around the hour mark. While you friend is no doubt disapointed to have got bent, the only way to be absolutely certain of not getting bent is to never go diving. I would ensure he is reviewed by a competent hyperbaric physician in the near future to talk through the implications of his bend. __________________ Andrew Bowie Rebreather-friendly Buddy
(Offline)

30th December 2006, 05:04	#6 (permalink)
cramerdn Obey my dog! Current Rebreather/s: Evolution Dolphin Other Rebreather/s: Dolphin Join Date: Dec 2006 Location: Townsville QLD Posts: 626	Re: DCI: What could have triggered it? Quote: (Originally Posted by Yann A.) Hi cramerdn, The depths mentioned are of course the Max depths… Oh course how silly of me to read what you wrote instead of knowing that Anyway, Has he been checked for Patent Foramen Ovale (PFO)? Info here... Patent Foramen Ovale As far as the beers? My rule is that I don't drink at all untill the last dive of the last day of my trip. (or sometimes if I have a one or two day full break and the San Miguels are really cheap ) But two beers the night before seams pretty conservative.
(Online)

30th December 2006, 06:03	#7 (permalink)
dteubner Pedant Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Mar 2005 Location: Adelaide, Australia Posts: 217	Re: DCI: What could have triggered it? Quote: (Originally Posted by abowie) Bad luck. DCI is essentially a statistical entity. Just because you "dive within the NDL" doesn't mean that you can't get bent, just that it is unlikely. To be honest that does look like a moderately provocative series of dives with (from a recreational perspective) reasonably deep maximum depths, shortish surface intervals and dives around the hour mark. While you friend is no doubt disapointed to have got bent, the only way to be absolutely certain of not getting bent is to never go diving. I would ensure he is reviewed by a competent hyperbaric physician in the near future to talk through the implications of his bend. Absolutely. When I do recreational diving medicals I tell the people that, if they decide to go diving, there is an inevitable risk of DCI. You can do things to decrease the risk but you cannot eliminate it. Whenever people post things like this there is allways dehydration, PFO etc etc etc. Maybe sometimes these are implicated but in the vast majority of cases the answer to "Why did I get bent?" is "Because you went diving". Dave T
(Online)

30th December 2006, 07:17	#8 (permalink)
Gobfish1 Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Join Date: Apr 2005 Location: Manchester UK Posts: 363	Re: DCI: What could have triggered it? surface interval 1h35 maybe you want to do a bit more SI , time between dives , your pushing bottom times by the use of depth change,s on the dives just to stay in side the no deco times of your computers , ha we all do it , You spent a lot of time in the water with 3 dives , Think its some bad luck, and maybe some bad thinking Average depth of 25m and a average 52mins for all 3 dives Average si was 85mis think you need to revaluate your dive times and si Glad to see no harm came of it ps your average dive , dive to 25m for 52:00 (53) on Air, PPO2 0.731, END 25 Deep Stop at 18m for 2:00 (56) on Air, PPO2 0.585, END 18 Deep Stop at 12m for 2:00 (58) on Air, PPO2 0.460, END 12 Norm Stop at 6m for 33:00 (92) on Air, PPO2 0.335, END 6 TOTAL DECO TIME: 37 minutes. DIVE RUN TIME: 92 minutes. average square profile dive / 3 dives = 12.3 mins not just a 3 min stop at 3m this is just one way to look at it from out side the box ps surface interval should be made to suite the diving, NOT to suite the dive boat DM so he can get back to dive shop by 4pm for a drink with his M8s __________________ Steve G Apparently not the only gay diver in the village http://drinkingliberally.org/blogs/o...nzee-glock.gif http://www.scubatunes.com/audio/vol01/mp3/HiTech.mp3
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30th December 2006, 07:19	#9 (permalink)
Yann A. New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Feb 2005 Location: Indonesia Posts: 49	Re: DCI: What could have triggered it? cramerdn, Oh course how silly of me to read what you wrote instead of knowing that I thought that when I worte: "the profiles were... well within the No-deco limits", and "...at no time during the dive did the diver went into deco." It would have been made obvious and clear enough that the diver hadn't spent his total time at depth but only "visited that depth for a short time... But then maybe not for everyone... Andrew, Dave Agree with you and an examination by a proper hyperbaric physician is planned. PFO seems vrey unlikely though, as the diver get complete medical check every 6 months for work. Thanks for your thoughts.
(Offline)

30th December 2006, 07:34	#10 (permalink)
abowie Fighting Girl Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: May 2005 Location: Land of Oz Posts: 574	Re: DCI: What could have triggered it? Quote: (Originally Posted by Yann A.) PFO seems vrey unlikely though, as the diver get complete medical check every 6 months for work. There's up to a 30% chance that the diver has a "probe patent" PFO because that's the incidence of PFO in the general population. So statistically either you, I or Dave T has one. It's most unlikely that a small one would be detected during royutine physical examination unless he actualy had the specific test for it. Whether it's worth looking for a PFO (not, in my view), and what it means if anything if he does have one (quite unclear in my view) is entirely something else. That's why I think he should speak to a suitably qualified hyperbaric doctor who can give him the facts so that he can make some sensible decisions about further investigations he might like to have, and further diving. __________________ Andrew Bowie Rebreather-friendly Buddy
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