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Nitrox instead of air for lower DCS risk?

Discussion in 'Ask Dr. Decompression' started by BigTuna, Mar 7, 2006.

  1. BigTuna

    BigTuna Solo Diver

    # of Dives: 200 - 499
    Location: NJ
    305
    1
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    I'm an old toad, but in good shape. I want to minimize age-induced risks of DCS. I've been diving on air, with depths mostly in the range of 60 to 100 feet. I'm usually a hoover, so I usually have less remaining air time than the no-deco limit, so I don't need nitrox for more bottom time (yet).

    When we were talking about managing my risk of DCS, my LDS operator suggested switching from air to nitrox. This is not a scam to charge me more for fills, BTW. If I were to adopt EANx32 as my standard mix, my normal depths would be comfortably below its MOD. Moreover, using EANx28 would cover me for all recreational depths. I'd use nitrox on "shallow" dives, too.

    The suggestion seems logical to me. There would be less nitrogen entering my tissues, therefore less to off-gas, therefore fewer bubbles and cascades, and reduced chance of "subclinical DCS" (NetDoc's term for post-dive tiredness and lethargy).

    What do you think? In general, would breathing nitrox instead of air reduce my risk of DCS?
     
  2. Charlie99

    Charlie99 Solo Diver

    # of Dives: 500 - 999
    Location: Silicon Valley, CA / New Bedford, MA / Kihei, Maui
    7,966
    158
    63
    Yes.

    It would take a low risk to an even lower level. Just as doing proper ascents will take a low risk to an even lower level.
     
  3. BigWhiteSquare

    BigWhiteSquare Solo Diver

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    PADI's standard line is that it does not reduce the risk of DCS, but I think that's just one big CYA exercise on their part. If they say nitrox has a lower risk, then they're also saying air has a higher risk.

    ___
     
  4. CD_in_Chitown

    CD_in_Chitown Divemaster

    # of Dives: 200 - 499
    Location: Chicagoland (SW Burbs)
    1,147
    8
    38
    It will certainly reduce the amount of nitrogen that your are on-gassing by a measurable percentage.
     
  5. Walter

    Walter Instructor, Scuba

    18,583
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    If you push the NDL on air and push it on nitrox, the benefit is more bottom time, but no reduction in DCS risk.

    If you dive the same time to the same depth, there's less risk of DCS with nitrox.
     
  6. H2Andy

    H2Andy Blue Whale

    # of Dives: 200 - 499
    Location: NE Florida
    29,646
    376
    0
    yeah, what Walter said, though i'd phrase it differently:

    if you dive Nitrox as though it were air (i.e. you use air NDL's), you are
    clearly lowering your DCS risk.

    if you dive Nitrox as though it were Nitrox, to take advantage of longer bottom
    times, then, no... you have the same risk of DCS as diving air to its equivalent time.
     
  7. daniel f aleman

    daniel f aleman Loggerhead Turtle

    # of Dives: 5,000 - ∞
    Location: Austin, TX
    2,191
    35
    48
    Assumptions, literally.

    I'm 48. My dive profile with nitrox is the same as if it were on air, I never dive below 100' feet on either and schedule the same bottom time on both gases. I HOPE that I receive the benefit of EANx...
     
  8. H2Andy

    H2Andy Blue Whale

    # of Dives: 200 - 499
    Location: NE Florida
    29,646
    376
    0
    lol, no

    we *know* that diving with less nitrogen means diving at a "shallower" depth
    than at the same depth on air. thus... same time at a "shallower" depth builds
    in extra safety against DCS

    since you are planning your dives on air, but diving at a shallower depth
    (due to the Nitrox), you are diving safer dives than regular air dives,
    DCS-risk wise
     
  9. Walter

    Walter Instructor, Scuba

    18,583
    334
    83
    In that case your risk of DCS is lower.
     
  10. daniel f aleman

    daniel f aleman Loggerhead Turtle

    # of Dives: 5,000 - ∞
    Location: Austin, TX
    2,191
    35
    48
    Who is this "we" Andy?

    I do not IN FACT know whether I am diving "safer" on EANx than that of air, I dove a gazillion dives on air to depths below 100' over twenty years - I'm still here.

    Now, as I've said, I stopped diving on air seven years ago completely (after Trimix 2)... so...
     

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