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Had a not so fun experience, any ideas?

Discussion in 'Near Misses and Lessons Learned' started by Princess Chris, Jul 30, 2019.

  1. Princess Chris

    Princess Chris Instructor, Scuba

    # of Dives: 500 - 999
    Location: Wellington, New Zealand
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    18
    Ok so I had a rather unnerving experience acouple of weeks ago during a dive and for the life of me I cannot figure out what the cause of it was.
    So I was diving a wreck (no penetration) at 40m, the plan was to descend down a mooring line on to the wreck spend a few minutes having a look then head up a slope to a shallow reef and finish off the dive there. I got a little distracted by a lion fish trying to eat a baby octo (who wouldn't?) and ended up going into deco. My computor beeped at me so I started my ascent in a calm and controlled manner and followed my comp instructions. This is when things got a bit screwy. At about 27m I had a strong feeling that I was going to lose consciousness. I managed to fight this off, signal to my buddy that I had a problem and pointed to my head. This continued for about 1/1.30 minutes. I maintained a safe ascent rate and made sure my buddy was right next to me. At about 20m I felt ok again just very confused.

    This is not a new dive to me, I have done it several times with exactly the same profile. I wasn't in sick, tired, hungover or unfit. There is just one variable that I can't seem to figure out. Only thing different is that I went a little deeper than planned but still doesnt explain what happened.

    If anyone could shed some light on the cause of the light headness then please let me know.
    Thanks
    upload_2019-7-31_12-18-45.png
     
    Snoweman likes this.
  2. Altamira

    Altamira ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Canyon Lake, TX
    1,679
    1,477
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    Did you test your tank for CO before your dive?
     
  3. Snoweman

    Snoweman Loggerhead Turtle

    # of Dives: 50 - 99
    Location: Atlanta, GA
    1,688
    674
    113
    Excellent question. Does CO or CO2 effects abate at shallower depths? I'm wondering why he would have felt better at 20m.
     
  4. Altamira

    Altamira ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Canyon Lake, TX
    1,679
    1,477
    113
    Snoweman likes this.
  5. RyanT

    RyanT Solo Diver

    # of Dives: 500 - 999
    Location: Maryland
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    1,458
    113
    Very likely, because with all gas components, the partial pressures will be reduced at shallower depths. CO would be my first suspect.
     
    Altamira likes this.
  6. DandyDon

    DandyDon Old men ought to be explorers ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: One kilometer high on the Texas High Plains
    48,650
    4,396
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    That article just sucks, as it totally misses the risk of overworked, hot compressors burning their own lubricating oil. It gives lip service to a risk but no real solution.

    Aside from that, you are partially right in that CO tainted gas would have a lessor effect at shallow depths on descent. It gets tricky on ascent as while PPO2 decreases as you go up, the CO already bound to your blood while at depth stays much longer so the effect can increase.

    Could have CO tainted gas have caused the problem described in the original post? Maybe. There's only one way to tell, best done before the dive. It'd be possible now if the tank has not been drained or refilled and a CO tank tester could be obtained.
     
    rjack321, RayfromTX and Snoweman like this.
  7. AfterDark

    AfterDark Solo Diver

    # of Dives: 1,000 - 2,499
    Location: Rhode Island, USA
    8,142
    3,613
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    A touch of vertigo? It does happen sometimes when we lose our frame of reference and or brain gets mixed signals. An ascent is probably a likely time for this to occur.
     
    Bob DBF, chillyinCanada and Steve_C like this.
  8. ChuckP

    ChuckP Manta Ray

    # of Dives: 200 - 499
    Location: Cozumel
    706
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    93
    I'd think CO would have had a longer effect, you might even have felt it coming on. I've had it above water and it just doesn't go away.

    I'd purely guess vertigo too....

    Any trouble equalizing, any full feeling in your ears after the dive?
     
  9. davehicks

    davehicks Barracuda

    # of Dives: 1,000 - 2,499
    Location: Seattle
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    Everyone on ScubaBoard has CO on the brain for every issue. Unless there is other evidence I would assume a simpler explanation.

    You dove to 43m /141 feet and got seriously narc'ed! This is why is quickly cleared as you ascended rather than perishing from CO poisoning. Everyone gets narc'ed at different depths and experiences vary, but at 141 feet it might be expected.

    Common symptoms of nitrogen narcosis:
    • poor judgement
    • short-term memory loss
    • trouble concentrating
    • a sense of euphoria
    • disorientation
    • reduced nerve and muscle function
    • hyperfocusing on a specific area
    • hallucinations
     
    Kmart921, MykaDives, rjack321 and 5 others like this.
  10. DandyDon

    DandyDon Old men ought to be explorers ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: One kilometer high on the Texas High Plains
    48,650
    4,396
    113
    No, not really, not at all. Not near enough. And others have suggested Vertigo, which is certainly a fitting possibility.

    His problem did not hit at 43/141 feet. He was almost halfway up. Narcosis doesn't fit.
     
    John C. Ratliff, RyanT and AfterDark like this.

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