My Adventure with type2 Decompression Illness

[curator]

Eagles Nest 5/12/2011
It was a dive I have done several times before, swim the upstream tunnel to the
back of the super room, turn around near the 700ft. marker, 30 to 35 minute bottom
time, maximum depth 270 feet, aproximately 1 hour and 30 minutes of decompression
time. My bottom mix was 30% helium and 17% oxygen, my deco mixes were 34%
nitrox and 100% oxygen for my 20 and 10 foot stops.
Let me add that I've done aproximately 1,200 dives, over half of which were in
underwater caves, and probably a few hundred or more have been dives deeper than
200 feet.
I didn't run out of gas or cut any of my deco stops short. I felt comfortable and relaxed
on the dive. I wasn't cold. The water in the ballroom and the upstream tunnel was
clear. It was a beautifull and uneventfull dive.
One big mistake I made was to go diving at all on Thursday. Wednesday I had
a stomach ache all day and felt very tired that evening. My wife and I both thought I
had a slight fever (our thermometer had a dead battery). I told my buddy I might not
make the dive. The next day I felt good. Still tired, but I wanted to dive.
We had completed aproximately 1 hour and 10 minutes of staged decompression.
I was doing my last stop at 15 feet, straddling the large tree trunk that descends the
slope, when I started to fall off the tree. I squeezed my legs around the trunk to stay
in place. I felt light headed, like I could be blacking out. I grabbed my b.c. inflator with
my left hand, dropped my oxygen regulator and put my bottom gas regulator in my
mouth. I initially thought I could be experiencing 'bad gas" and was in danger of
blacking out. I was trying to deploy my nitrox regulator but with my head spinning
I felt as if I was riding a mechanical bull in some bar after drinking several beers.
I went through all 3 of my breathing gases before going back on oxygen, realizing
that my 2 deco mixes were good, having been used on previous dives with no
problems. I also realized that I was not passing out or even light headed. I was dizzy
and off balance but I could still breathe underwater, and this was good because I
still had 20 minutes of decompression to go and I needed to stay down at least that
long. The next realization was both frightning and fascinating. I was experiencing,
what I learned later was called rotational vertigo. As I lay on the tree trunk it
appeared to me as if an endless procesion of trees was moving past my field of vision
very fast from right to left. This made me off balance but if I closed my eyes I felt
normal. So I basically layed on the tree for 20 minutes with my eyes closed,
occasionally opening them to see if my world had stopped spinning, marveling at the
visual hallucination I was experiencing. I wasn't sure how the swim back to shore
would go as dizzy as I felt. When my deco was up I moved down to my buddy and
signaled him that I wasn't o.k. He handed me his slate to write on but just then I
started to throw up. I was considering extending my decompression but when I got
sick I realized I needed to be on the surface. I told my buddy that I was surfacing and
swam to shore without too much difficulty. When I surfaced my buddy's girlfriend had
a camera pointed at me and asked me "how was it?" I managed to say " good, I'm
sick" before turning my head and throwing up again. She ran to the truck and brought
me a bottle of water and then proceeded to carry my tanks and other gear away as I
struggled out of it, for the most part keeping my eyes closed. I stumbled to the truck,
stopping to throw up before getting in and lying down on the backseat. I also felt
lethargic and think I briefly fell asleep several times during the drive out of there.
It turns out that I had inner ear decompression illness, possibly from something called
isobaric counterdiffusion. It appears that when switching from a helium rich breathing
mix to a nitrogen rich mix, nitrogen, being more dense, can block the helium from
release, resulting in inner ear decompression illness.
I was flown at low altitude to Florida hospital in Orlando for 2 U.S. Navy table 6
chamber dives. my symptoms improved with each dive but when I got out of the
hospital 2 days later I still was a little off balance.
The question remains as to why I got bent on a dive profile very similar to dives I
have done several times before. It might just be because I didn't feel well the day
before. I'll probably never know for sure.
Also, my buddy started experiencing severe abdominal pain after the dive. He
had bruising from his midsection down to his thighs. He was flown to a Tallahasse
hospital and chamber treatment for type 1 D.C.S. He said that after 1 and 1/2 hours on
oxygen his symptoms were gone.

[JamieZ]

I stopped reading when I read 17/30 bottom mix for max 270ft. Am I reading something wrong or is it a typo?

[adam0321]

15/50 would be best but cost a bit more with the he. It can be done on 17/30 but I would not try it. I would not think icd. Your he mix was not that high. But I am no expert. I would have thrown another trimix in there for deco. Sounds to me like dcs 2 alright. You had neurological symptoms.

You said they did 2 tt6 on you? That's odd for that depth. The max depth for a tt6 is 60' and I have,never herd of doing two back to back. They can be extended but not doubled. Was it a 6a table? Those are used more for the deeper dives.

They should have taken you to 60' and put you on o2 you were not able to come out on a tt5 since you had neurological symptoms. If you had relief within 20 minutes then its a tt6 probaly with max extensions.2 at 60' and 2 at 30' if you did not have relief within 20 minutes at 60' then it should have been a 6a. Or maybe even something longer. As a general rule you don't commit to a table on surface. You go to 60' throw the pt on o2 and see what happens. If you had recurring symptoms in the chamber they should have shifted to another table.

As to why you got bent? Have you been checked for a pfo? Systemic infection could have made you more likely to dcs.

Glad your ok.

Sent from my Eris

[adam0321]

Also looking at it you went from a mix with 53% n2 to a mix with 66% n2 not that big of a switch. My understanding is icd becomes a risk in switches of gas where there is a 50% or more difference. And from what I have read icd displays as skin bends most of the time. It is possible to have inner ear dcs with out icd. Which the vertigo if severe enough could cause the vomiting. So you may have not had true neurological symptoms in the classic sence of weakness or paralysis. I am a bit rusty on iedcs so not sure if it is classified as type two dcs. For instance sever skin bends or cutis marmorata (spelling) by definition is dcs type 1 bit we treat it as dcs type two. For you to have been labeled with dcs type two you should have had pain in the parts of your body covered by shorts and a t-shirt or neurological symptoms. And running your mixes on v-planner you should have had around 1 hour 40 minutes deco. Did you use tables or just let your computer deco out?

Dehydration? Previous dives? Fatigue?

Sent from my Eris

[Caver95]

Well, your END was 170, there where two guys some years back that ran the same END and there is a memorial there to one of them. You had a ppo2 of 1.56 for 30-35minutes on the bottom, I don't know who taught you to dive mix, but the max for cold working dive should be no more than 1.4 and even then I like to use a 1.2. 1.6 ppo2 single exposure 45 minute for that portion of the dive your CNS was 66-77% I am not sure what your profile was but I would be will to bet that you got on your 34% at 120? racking up that CNS clock some more. Your lungs are getting pretty inflamed at that point and less proficient at off gassing. I bet after that ride your lungs really hurt. Off the top of my head with all that n2 in your mixes I would be willing to bet you did not do enough deco. What was your profile and what software did you use, did you use a computer? I hope you recover with no lasting effects, other than a little more respect for mixed gas diving.

[adam0321]

After doing a little reading inner ear dcs is treated as dcs type 2. It seems that you had some very common symptoms of IEDCS. I thought your PPo2 was a bit high aswell. I would not venture into that ppo2 level unless at complete rest, and not that deep. You cns% as stated was around 76%. I thought o2 tox at first. But it seems you had classic IEDCS. COuld have come from the gas swith but I doubt it. Did you have any hearing problems?

this is from Bove and Davis diving medacine

"Divers who experience symptoms during or shortly after switch from an air enviornment during decompression from a deep he o2 exposure should be switched back to the presymptom heo2 atmosphere and subjected to prompt recompression."

[Jay]

Verry Sorry to hear about your accident. I too am curious about what software you used and the conservatism. It seems like you are a little short on deco for the programs I run..
Can you tell us more about the dive profile? Did you start the dive on your bottom gas or 34%? Did you calculate a few minutes at 220-240 for the initial swim or use just 270 as a bottom and auto calcualted deco stops and switches?

Was your buddy using the same gas? The same profile? It seems odd that you both took hits. Were the gasses analyzed before the dive? After the incident?

Folks, please keep your questions and comments civil. It would be great to get more info about the dive without alienating him. That what this section is about.

[Tegg]

Folks, please keep your questions and comments civil. It would be great to get more info about the dive without alienating him. That what this section is about.

This is the most important thing said in this thread other then the OP's posts.

[chuuk]

This is the most important thing said in this thread other then the OP's posts.[/QUOTE]

When I started reading this this morning-the replies made me wonder if I would ever put an article about an incident on this forum. this should be a learning experience. In Canada we have a forum that comes from around Lake Ontario which just destroys people who put in a comment or are not part of the c.lick

[FW]

If anyone wants to post an incident, and not have your name on it, send it to a moderator, and we will post it for you. I have been doing that for awhile, but some people seem to think it was me that had all the incidents