DCS incident analysis requested

[Spoon]

Guys i hope you dont mind me posting a thread reqeuesting analysis on my incident last saturday regarding my close call with dcs. I am requesting this becasue a lot of members have requested an analysis of my incident so that they can learn from my experience and avoid it in the future. i am also curious about what really happened to me that day.

i am quite confused because there are too many factors to point the finger at and the whole lot of them probably brewed into a wicked mix that made me more prone to dcs that day. i have learned a lot from my experience and am quite lucky to escape without real damage. its also a humbling experience that no matter how much you think you are prepared or ready for your dives, mother nature can always leave your best laid plans in tatters. il be more careful next time...


here is the thread i posted in the deco section :

What happened? skin bends?
guys i am quite worried i think i may have gotten skin bends, i did a search and reviewed most of the skin bends cases and my symptoms are different. anyway before going on i will give you my dive profiles for the three dives i did yesterday.

Dive1: 125 feet max, 49ft ave, bottom time 51 mins. did necessary stops. we even did our obligatory deco stop for 5 mins . aside form that we were shallower than 30 ft for the remaining part of the dive and even did our safety stops.

surface interval 2hours 20 mins

dive2: 107 ft. max, 44ft ave, bottom time 31 mins. this dive was very conservative and we decided to abort it early because there was a slight surge shallower than 20ft. soon after this dive i noticed a small blotch on my tummy. it was sore and i was attributing this to sunburn because i usually sun tan during my surface intervals.

surface interval 2 hours 30 mins

dive 3: 132ft max, 53ft ave, bottom time 31 mins. got hit by a strong downdraft and made it to 132ft, ascended slowly til we leveled off at around 100ft. most of the dive was shallower 90 and made sure we were within our ndl times.

about an hour after the last dive, my blotch on the stomach enlarged and it was extremely sore. like the feeling of a raw sunburn. very painful. on the way home i got the chills and had fever. the blotch was in my tummy area only. also noticed shortness of breath.

next day i am fine and the blotches are visibly lighter. still abit sore. i seriously think that it was a sunburn since i have gotten this before. i dint exhibit other signs of dcs like sore/painful limbs etc. curious?

i have noticed that this is the 4th time in months that i have gotten fever after a day of diving. in my previous posts it was either stung by venomous animals, tropical hypothermia, not wearing the right exposure protection, lack of sleep, low immune tolerance etc. first time i had a blotch materialize was yesterday. im starting to wonder if those past dives i exhibited slight sympotoms of dcs? guess not symptom was just fever?

Forgot to mention: i did my 6-8k run in the morning. could this have contributed coupled with my lack of sleep?

taken from Gregor's post: Re: predive exercise

I think it is a real mistake to try to translate military research in predive exercise to civilian sports diving. The military personnel used in the french study cited by CHip104 and other military studies are in excellent physical condition unlike many sport divers.

Rigorous exercise can have opposite effects on physiology depending on how well conditioned you are at the time.

Rigorous exercise in an unconditioned individual can cause subclinical tissue damage and inflammation and that, I believe, is an invitation to DCS.

On the other hand, inflammation would be minimal in a well-conditioned individual and I can imagine other ways in which pre-dive exercise could adjust a person's physiology so as to reduce the odds of DCS provided 1) that the exercise in question was within or nearly within the linits of the person's normal exercise tolerance limits and 2) the exercise caused no tissue damage. (Bowling is less exercise than running 6-8k but is more likely to cause sholder injury.) The military reseach cited above backs up the contention that exercise is preventative.

Now Spoon says he runs 6-8k so is probably in good shape but he doesn't say how often he runs it. If Spoon normally runs 6-8k/day I would suggest it has a preventative effect on DCS. But if he runs it only every other day or every third day, I would counsel him to take much more conservative dives after running on running days than on non-running days.

I would further suggest that if he runs 6-8k after a night with little sleep, that exercise is more likely to cause an inflammatory response (pro-DCS) than exercise conducted when well-rested. Furthermore, Spoon is more likly to run "sloppy' after little sleep... to run in such a manner as to put greater stress on his joints, muscles etc.

Any deco docs out there want to comment on the possible effects of inflammatory processes in DCS?

my response to gregors post:

i run an average of 4-5k 3 times a week for 45 mins in a treadmil at a pace of 7kmh i rarely go beyond 5k and rarely jog on real pavement. say maybe once or twice a month at most. and all of my morning cardio sessions are conducted after getting an average of 7 to 8 hours of sleep in the gym treadmill. that 6-8k run was quite rare becasue i hardly go beyond 5k and it was also done on pavement which is also a rare thing. Gregor also has a point when he says i could have been sloppy, which in fact i was but not becasue i wasnt well rested but beascue of the hard pavement on my joints. i managed but i have to admit towards the end of the run my joints were sore but not painful.

 

[Tollie]

Ok my friend here is my 2 cents. I think you were tagged.

The profiles you are running are collectively too deep. That coupled with poor pre dive conditions i.e. lack of sleep and perhaps too much exercise. You did not mention other factors such as stress or hydration status but surely the downdraft on dive three was unexpected and you worked much harder than you thought you have to.

Using tables, as you know you blew the top off them and using average depth is a tricky and not so conservative a way to go. Its tough to actually figure out what an average depth is and then what to do with it once you have got a figure.

As a GUE trained diver you know enough not to blindly trust your computer (if you use one) as the computer cant factor in dive conditions or your own bodies readiness to handle the dives you outlined. As a GUE diver I’m sure that you tended to deep stops as well (Right?) if not then you may have had a problem in the time/depth shape of your ascent.

In short pleased take it easy and take a bit better care of yourself prior to the dive.

I’m curious to see what others say.

 

[jonnythan]

Sounds to me like you ran your computer into the ground right past the NDL on profiles that were way too deep while on air.

I'm not sure where your average depth is coming from or what your bottom times indicate. Personally my 'average depth' numbers are my average depth on the bottom, and I stop counting the depth and bottom time when I begin my ascent. On a dive where my average depth were 60 feet and bottom time was 50 minutes, a dive computer might display average depth of 50 feet and bottom time of 55 minutes.

In any case, you obviously knew you were blowing right by the NDL and even into deco by virtue of your computer, and yet you chose to go right back in the water for another aggressive dive, and then one more! IMO you should not be surprised by getting bent in this instance, and the *first* response should have been a call to DAN, not a post on the internet.

 

[Spoon]

As a GUE trained diver you know enough not to blindly trust your computer (if you use one) as the computer cant factor in dive conditions or your own bodies readiness to handle the dives you outlined. As a GUE diver I’m sure that you tended to deep stops as well (Right?) if not then you may have had a problem in the time/depth shape of your ascent.

i in fact use a computer in all of my dives. even though gue doesnt recommend it i still carry one in conjunction with my dive tables which are permanently stored in my wetnotes. dive number two was well within my dive plan and profile. in fact i was well within my ndl times at depth. in dive # 3 i was within my dive plan except for the downcurrent which took me 25 feet more than dive #2.

i remember my gue instructor saying that repetetive dives wherein succeeding dives MUST be shallower than the previous was a misconception and that they have tested going deeper on rep dives safely. i clearly remember being taught that the succeeding dives can be deeper but not more than 40 ft of previous dive. i even questioned him about it and told him that this is not what padi and all other agencies preach but he said that gue trained divers were doing these profiles all the time. there all in my notes taken from class. at this point i dont know what to think.

 

[Doc Intrepid]

Spoon, I'm thinking along the same lines as Tollie. My remarks are NOT meant to be critical, merely observational. Taking both a PADI and NAUI set of recreational (air) dive tables (I don't have a "Wheel"), there's simply no way that the "Residual Nitrogen Time" from the first dive would allow you to do the second, and obviously the combined RNT from the first two dives wouldn't have allowed you to do the third.

So you weren't using tables to plan your dives (?). Your account doesn't note whether you were using Nitrox or Air. As you're beginning to walk the path, I'm sure you weren't using a computer. So it isn't clear how you planned these dives.

Regardless, you did three dives below 100', two of which were within 5 feet of 130' (both ways), with a total collective bottom time of nearly 2 hours.

That's pushing it in anyone's book.

Glad to see you're ok and doing well. Clearly these are multilevel dives you're doing, so if you're using a computer try setting the conservatism value up higher; another option might be to use the software that comes with the computer to plan out several multilevel dives similar to these profiles and see what your residual gas values are. Spend some time playing with the software. Take things a little easier, dude! Another variable not touched on here is discussed on the "ascent rates" thread; basically I assume you move up slowly to shallower depths while on ascent, but your RATE of ascent would make a huge difference on dives such as these. I suspect your rate of ascent added to rather than subtracted from your level of on-gassing. There is a paper referenced in the other thread you should print out and read, see the post by Charlie99 on the DAN-Europe doppler study.

The best lessons of life are either painful, humiliating, or expensive. I think you were pretty lucky!

Regards,

Doc

 

[jonnythan]

Good point, Doc.

Spoon, how exactly did you plan these dives? Was it with your computer?

 

[Charlie99]

1. Is it possible to download your profiles and post them?

2. It's clear from your description that you were bent before you went in for your 3rd dive. Although dive #3 may have aggravated your condition, you already had skin bends before it. So at least the initial analysis should concentrate of dives 1 and 2.

Of course, the big problem in cases like this is that it's all a matter of statistics/luck or (un)luckiness. We can shift the balance of luck for us or against us, but one could repeat a profile a hundred times without problems,and then get DCS on the next one.

EDIT: One more question --- on your second dive you mentioned there was a surge. Did this cause your depth to go up and down repeatedly?

 

[Spoon]

1. Is it possible to download your profiles and post them?
I dont have the uplink software from my computer but il find a way to uplink them.

2. It's clear from your description that you were bent before you went in for your 3rd dive. Although dive #3 may have aggravated your condition, you already had skin bends before it. So at least the initial analysis should concentrate of dives 1 and 2.
could be but the last thing i thought of was the bends. i dint exhibit any of the symptoms i just thought it was sunburn as did most of my buds bec i was tanning in my surface intervals.


Of course, the big problem in cases like this is that it's all a matter of statistics/luck or (un)luckiness. We can shift the balance of luck for us or against us, but one could repeat a profile a hundred times without problems,and then get DCS on the next one.

EDIT: One more question --- on your second dive you mentioned there was a surge. Did this cause your depth to go up and down repeatedly?

yes towards the end of the dive we had a mini saw tooth profile but i would say variance of 5 feet shallower than 20ft.

 

[DameDykker]

i remember my gue instructor saying that repetetive dives wherein succeeding dives MUST be shallower than the previous was a misconception and that they have tested going deeper on rep dives safely. i clearly remember being taught that the succeeding dives can be deeper but not more than 40 ft of previous dive. i even questioned him about it and told him that this is not what padi and all other agencies preach but he said that gue trained divers were doing these profiles all the time. there all in my notes taken from class. at this point i dont know what to think.

If you use you computer software you'll properly see, that doing the deepest dive last will severly limit you NDL. Does your table planning (?) take taht into account?

The theory is that mico bubbels initiated in the former dive will be recompressed and forced into the tissues. Thus breaking out with a higher rik of DSC on the ascend from the deep dive.

So I also think you were very lucky.

 

[Ben_ca]

i remember my gue instructor saying that repetetive dives wherein succeeding dives MUST be shallower than the previous was a misconception and that they have tested going deeper on rep dives safely. i clearly remember being taught that the succeeding dives can be deeper but not more than 40 ft of previous dive. i even questioned him about it and told him that this is not what padi and all other agencies preach but he said that gue trained divers were doing these profiles all the time. there all in my notes taken from class. at this point i dont know what to think.

But this is with the proper gas. You were diving these profiles on air right? Which tables were you diving?