O2 convulsion

jhaaja

Here is a brief description of my accident from last July. The text is the same that I sent to DAN.

I was diving an Inspiration rebreather in Baltic Sea. The dive was trimix decompression dive with max depth of 74 meters. The dive went fine until the last minute of my 12 meters decompression stop. At the last minute of my 5minutes stop I noticed that something was going wrong. The symptom that I reacted to was contractions of my diaphgram muscle. At first I thought it was normal cold shivers, but it got stronger quite fast. Maybe the time frame from first small contraction to convulsion was about 30 –60 seconds. I had enough time to close the mouthpiece and go off the rebreather loop. I had a EAN50 stage with me, but the valve was closed. I also got the valve opened and the regulator hose behind my neck. I lost consciousness the same time I was trying to put the reg in my mouth.



My dive partner was close to me all the time and he noticed immediately that something was wrong when I came off the rebreather loop. After I convulsed and lost consciousness he waited for the convulsion to stop and then started to bring me to surface. He insured that my airways were nicely open and monitored that gas came out from my lungs. He also kept the reg against my mouth to prevent water entering my lungs. He got me to the surface in about 6 minutes.



On the boat we had good organization and my gear was removed quicly and given mouth-to-mouth because I was not breathing. After two blows I started to breathe. After that I was unconsciouss for about ten minutes. Then I woke up and was feeling quite good considering what had happened. By the time I woke up the sea rescue helicopter was on its way. I brethed oxygen on the surface from a scuba regulator. I also took one pill of aspirin and little bit of water. My lungs were basically clean off water. I never had to cough at all.



I and my dive buddy were flown to Turku for further treatment. There was a doctor in the helicopter and I was given some fluids to the vain. In Turku my lungs were x-rayd and some other basic tests. I never felt any DCI symptoms but I was put in to the chamber for safety. The treatment lasted 6-7 hours and I almoust convulsed again 6-7 times in the chamber. I noticed the same symptom in the chamber as in the water and took the O2 mask off before the convulsion. I was not able to breathe O2 at any depth (18m, 9m, 6m) for longer than 10-15 minutes at a time.



I was released from the hospital on the night of 5th of July. The doctor ordered me not to dive for the following three weeks.



When the convulsion came my CNS% was below 50% according to the calculations used today. The Rebreather was tested before and after the dive and it was working perfectly. The day before I had done a dive which lead to near 100% CNS%. The surface interval between the two dives was over 28 hours.


JH
Finland

Dave Young

Thanks for sharing the details of your accident with us, and I'm very glad that the out come was a good one. Your dive partner certainly did a commendable job in assisting you.

It demonstrates that when something might go wrong whilst on a rebreather, it can creep up from nowhere and very quickly.

schford

Thanks for sharing and great job by your buddy! Have some green and glad your OK!

When did you recognise it was on O2 hit? Is that what led you to come off the breather?

Sounds like a slick rescue operation!

Thanks

Stuart

Nad

Wow, glad that you're ok, and glad you had a good buddy with you.

Best,

Nad

__________________
The Impossible is often the Untried

abowie

Nasty. I'm very glad to hear you survived this; your buddy deserves a medal!

Any idea what your PO2 actually was when this happened?

__________________
Andrew Bowie

Rebreather-friendly Buddy

Drmike

Nasty situation. Glad it worked out well you clearly have a good buddy and dive support team.


Have you had any problems since? Did you find out what was predisposing you to a hit?

When my old buddy took a hit the unit also checked out fine after the dive but it wasnt until we tested it during the dive (increasing temp, ppo2) we found PPO2 creap due to 3 faulty cells. I presume that was ruled out in this case.

I admit when I have a last stop longer than 45mins and Im alone in the water I do worry and actually my practice is to clip myself to the deco platform in case of convulsion (wont sink or ascend then and Im wearing a FFM)

Only had the twitchies once and it scared the crap out of me.

Glad you were ok and thanks for sharing - could have been a different story had it happened earlier in the deco or had you been solo.

Food for thought.

__________________
Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you

dave t

JH glad you are ok. I have had to rescue someone who had an o2 convulsion and it is a VERY scary affair!

Can I ask how did you test the Rebreather after the problem? did you test it at the po2 of the incident? how old are your cells? are they AP ones?

Thank you for sharing your ordeal, I hope we can learn somthing from it

Dave

db8us

JH ! Good that it went OK ! What was your pO2 at 12m ?
Good that there are still buddies who are not afraid of skipping deco !

I still remember the accident where one diver let his buddy up to the surface and die and still stay down...

Pierre Farrugia

Hello,

First glad that you are ok. When you were on the boat, did your buddy had DCI symt. ? Can you post your profile and what were you using for deco calc. ? I am asking the above question, because, let say you had high oxygen all through the dive and get an oxygen hit, then your deco should have been very low but your buddies' not! I think this would explaine some things.

__________________
Pierre Farrugia

My wife told me " If you don't quit diving I'm going to leave you"
My reply " God, I'll miss you"

www.atlam.org www.divemed.com

jhaaja

Thanks for comments everyone. Some answers to questions:

To Schford:
I started to feel that something is going wrong, but I did not think that it wassO2 issue. The symptom was so odd, diaphgram contractions. I also had a reg attached to my dil-tank under my chin, but I made the decision not to use it. The reason was that I could not be sure that the dil-gas was ok. I decided to switch to the EAN50 bail-out stage that I was carrying.

About the ppO2:
My unit is a classic YBOD and 4th cell connected to VR3. I am convinced that the ppO2 never went over 1,3 during the dive. The 4th cell was during the dive 2,5 months old and the three YBOD cells about 11 months old.

The YBOD cells still react nicely and I can reach 1,55-1,6 when I do an oxygen flush at 6m and the unit is calibrated using O2% of 98%.

I can attach VR3 ppO2 graph from the dive and I think I have also the dive profile somewhere.

To DrMike:
I started diving 2,5 weeks after the incident. The first dive was quite horrible. I was a bit paranoid throuhout the dive But I went back to water again the next day. Now I amdiving basically the same way as earlier, but I use lower ppO2 all the time. I now use 1,1 and depending on the dive also O2 flushes if it is needed during 6m stop.

I am now even more meticulous about team work during dives. I won`t accept that dive team members just wonder around while in deco. They need to stick together and be aware all the time. Full face mask could be nice to prevent drowning if you get hit. I was wise and did not start breathing while under water That is why I got only a small amount of water in my lungs.

My VR3 had around 100mins of deco left when the convulsion started. Our plan was cut with vplanner and according to that plan I had around 50 mins of deco left. The dives average depth was 41,3 meters.

I have been thinking if the medicine I used had some sort of influence to the hit. I had placed a Scopolamin patch (used to prevent sea sickness) behind my ear a day earlier. I also had taken one Aerius antihistamine tablet the same day. I had used scopolamin earlier and also Aerius without any problems. It is impossible to say did they influence to the hit or not, but for sure I am not using those again if I am doing deeper dives.

You can see the dive profiles from my site:
www.hut.fi/~jhaaja/dive-profiles.pdf

The ppO2 graph:



I really can thank my dive partner for saving my life. He was diving OC and also had the same amount of deco left. He brought me to surface and then went back and started the deco scedule from 15m again. Also the surface crew was very efficient and that also helped to save me. And finnish Coast guards Super-Puma helicopter is also quite handy tool for sea rescue