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Skin bends...

Discussion in 'Ask Dr. Decompression' started by Pebbles Photo, May 13, 2019.

  1. michael-fisch

    michael-fisch Manta Ray

    # of Dives: 2,500 - 4,999
    Location: Germany
    I'm slowly coming to the conclusion that what I'm doing is directed at the wrong crowd. It's like trying to explain athiesm at a pentacostal rally - it ain't gonna work.
    If on the other hand, you are USUALLY diving trimix on longer deeper dives, you might want to look into it since there is no other diagnostic tool that can be used immediately after exiting the water. Every other method, although having it's place, is geared to deciding treatment, while in a hospital setting.

  2. Dominik_E

    Dominik_E Nassau Grouper

    First, I would simply suggest to do away with the ad hominem. It never helps, Michael.

    The large veins in your neck transport blood mainly coming from your head, I think this is generally accepted here, right? Any bubbles you detect in them would thus probably have to originate somewhere in the head, with the central nervous system being the only plausible area of origin, right? And you probably also agree that one will always hear something when doing the ultrasound in such a setting. So I am sure you agree it is not immediately clear why this should be a good place at all to quantitatively search for venous bubbles, as the brain tissue is generally accepted to be very fast, and you will not do your ultrasound after an SLBM-style ascend, right?

    That it is the only thing that can be done with a dry suit on does only mean anything if it is at least something that works...
  3. Duke Dive Medicine

    Duke Dive Medicine Medical Moderator Staff Member

    I don't think that's quite the case. Your rationale for using Doppler on a jugular vein as a predictor for decompression sickness and a measure of effective decompression has been questioned by multiple people based on anatomy and science. I'd say again that if you are detecting Doppler bubbles in a jugular vein ten minutes after a dive, even a trimix dive (helium being a faster gas and associated with increased VGE: [abstract] DECOMPRESSION SICKNESS AND VENOUS GAS EMBOLI IN HELIUM AND NITROGEN DIVING), the rest of your body probably has a lot more bubbles in it than you're seeing in your jugular vein and you may be avoiding DCS only by sheer luck or your own individual physiology. If it's being done as widely as you say though, it may be worthy of a formal study.

    Best regards,
    The Chairman likes this.
  4. Miyaru

    Miyaru Tech Instructor

    # of Dives: 2,500 - 4,999
    Location: EU
    Other method: a phonecall to DAN, directly after a dive in case of DCI suspicion, is not in a hospital setting.
    Although the hyperbaric medical doctor you'll get on the phone is not able to determine bubbles, (s)he is able consider dozens of other signs and symptoms during the initial interview and decide if a chamber treatment is validated.

    Throughout the topic, reading between the lines, I get a sense of frustration caused by a former DCI incident which could have been handled better. I agree that many hospitals have no knowledge of DCI, which is one of the reasons why a phonecall to DAN is the best first option in case of DCI suspicion.

    The idea of DIY Doppler is certainly interesting, but the arguments against use of the jugular vein weigh a lot heavier in my opinion. As for "Unfortunately, many of us that learned tech diving in the last few years, never really learned it, but are sure that they know everything about everything", I think that every single tech diver will immediately agree that the more knowledge we gain about decompression, the more we realize that we only know a little bit about it. Well, almost every single tech diver....
    Pweintz likes this.
  5. mac64

    mac64 Barracuda

    # of Dives: 5,000 - ∞
    Location: Ireland
    The ability to check a diver for dcs at the scene would be brilliant, two friends of mine have suffered life changing injuries because late getting treatment. Is there a research group that would be willing to work with you.
  6. michael-fisch

    michael-fisch Manta Ray

    # of Dives: 2,500 - 4,999
    Location: Germany
    Doubt it very seriously, you have seen here what the establisment thinks about checking for bubbles in your neck, or a layman self diagnosing if he is going to get DCS. Their methods are certainly better, but aren't available right after coming out of the water. I would love to have good cardiologist standing right there on the 6Pack with a 2D Huntleigh or 3D dopper instrument, but it ain't gonna happen and I can't afford it either.
    If In doubt, call DAN since by asking you a few questions they are in a much better condition to diagnose why you can no longer walk and are having trouble breathing, than you could. (Why do the medicos always assume that only they are right and that the patient is an idiot?)

    The funny thing is, my experience has been that almost every diver has bubbles in the jugular after surfacing from a TMX deco dive and whats important is how many bubbles.
    Personally, I have found that as long as you can easily count the bubbles, you are probably OK and if there are enough bubbles that you can no longer count them, you'll probably need help soon. When you call the emergency in, remember to use small words for small minds and don't let your sentences be interrupted by the person on the other end of the line, who will try to organize a helicopter to the nearest hospital. Whoever you're calling for will not be helped by a hospital that doesn't have a working treatment chamber and a chamber that needs 4 hours to become operational is worse than useless.

    The occasional mild pain in a shoulder or hip usually goes away by itself in a day or 2 - faster with a few hours of surface O2. The guy who taught me that trick 20 years ago was named BIll and had a 440cuft O2 tank in the bed of his pickup connected with a hose to the FFM located next to the drivers seat in order to breath O2 on his way home and another O2 tank in the livingroom of his singlewide 10 miles from Ginnie so he could watch TV while slowly losing his pain. His theory was that the more often you get bent the easier it was for your body to get bent, and he was diving every day the caves weren't washed out.
    Get the cheap Korean Doppler that I mentioned and try it out on yourself and your buddies for a while before you start diagnosing, when you finally hear way more bubbles than you are used to hearing you'll know somthing is very wrong. Lots of familys buy them in order to listen to the fetal heartbeat, 4 months later they no longer need it and are being kept awake by the cries of a hungry baby at all hours of the day and night. That is when you can buy it, slightly used, in Ebay for a little bit more than half price (No! the Doppler, not the Baby!)

    So, now I have upset everybody from the DCS experts to the divers that think they know something too.
    mac64 likes this.
  7. The Chairman

    The Chairman Chairman of the Board

    # of Dives: I just don't log dives
    Location: Cave Country!
    Agreed. Blood and neural tissues are among the fastest groups to on/off gas. It's impossible to infer other tissue groups from a single data point. Risking your health on such bogus science just doesn't make sense.
    Few like bogus science. Your friend was was bent needlessly by following such. If you can't learn from the collective wisdom here, at least learn from the mistakes of others.

    Note: Denial is the biggest problem in diagnosing DCS. If you feel you might be bent: CALL DAN. Do yourself a favor and make sure you have DAN's insurance. As someone who just broke their leg on a trip to Fiji, I can tell they treated me right. No, I've never been bent, but I've done a few chamber rides "just in case". No harm was incurred by that and I had peace of mind knowing that the pains were actual muscle strains and was able to treat them appropriately.
    chillyinCanada likes this.

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