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Oxygen at 30 ft. You tell me all about it, big time. gazela wrote: > > Gee Trey, other than spouting off and not being able to read English, > what other talents do you have. Who said anything about oxygen at 300 > feet? Given the depth of experience that the Navy and commercial divers > have versus the death rate of morons who keep trying to reinvent the > wheel, I'll stick with the former. > Wen > > Trey wrote: > > > > Give me a break - this is total crap. 200 cubic feet? I used 100 cubic > > feet to decompress from 6 hours at 300 feet. Oxygen at 300 feet with no > > mask following an exposure with an injyre diver ? Idiot, you need to > > shut the f up. You have no experience with this, you have no idea what > > you are talking about, and Pyle is full of shit - he knows how to get > > bent, and that is about it. The Navy manual is dead wrong as well. > > > > We do this al of the time and do it correctly and the result is > > generally no chamber at all. Get a clue. We do so much experimenting > > with deco that we have a lot of these situations. > > > > gazela wrote: > > > > > > Being new to the list, I've been (appropriately) keeping quiet. > > > However, this is subject that I have researched rather extensively. > > > I think the original question- what do you do when you are unreasonably > > > distant from a chamber and you get symptoms- is a good one that needs a > > > simple answer. IWR is practiced in Australia and Hawaii and they have > > > already worked out simple protocols. Also the Navy Dive Manual has a > > > protocol for IWR in its chapter on decompression injury treatment. > > > The key to any emergency treatment is KISS. If you give yourself too > > > many choices, or the treatment requires too much judgment, the error > > > (read worse injury) rate rises rapidly. > > > Two basic bits of background that you probably remember from your basic > > > OW course (if you managed to stay awake). Bubbles grow exponentially- > > > the larger the bubble, the more rapidly it grows. Commercial and > > > Military diving allows 5 minutes between surfacing and recompression in > > > a surface chamber. Second, at 33 fsw, gas volume is half that of the > > > surface. > > > The basic rules common to IWR protocols call for two things- get back in > > > fast, and get to at least 9 meters. They also call for using oxygen. > > > If you don't have a rebreather, you're going to need alot (Pyle suggests > > > 200 cu ft). The principle is to get the oxygen, get to 30 feet and stay > > > there at least a half hour. This is extended to an hour if there are > > > neurological symptoms. If the symptoms do not go away, then stay an > > > extra half hour before beginning ascent. If you don't have enough > > > oxygen, stay at 9 meters until it runs out, then switch to air (or > > > nitrox if you have it) and begin a slow ascent immediately. > > > The different protocols allow for different types of ascent. The > > > simplest is to come up at 4 minutes per foot (12 minutes per meter). > > > The alternative is to come up at 1 foot per minute and make 45 minute > > > stops every 10 feet. > > > These protocols come pretty close to reproducing in water what the Navy > > > Tables do in a chamber when you look at the physics and the > > > neurophysiology. > > > There is only a minimal amount of advanced preparation required for this > > > type of IWR, but it should be thought out ahead of time to avoid panic, > > > confusion, and danger. > > > If you're using air, the recommendation is to go 10 feet below the depth > > > where symptoms are relieved, or 165 feet max then start a staged > > > ascent. The last 9 meters should be on oxygen if you can get any. > > > Even if you're within reach of a chamber, if you have the support > > > available, I would agree with the concept of going back in to 30 feet on > > > oxygen until the air ambulance is there to get you. > > > Also, if you are going someplace remote, if you don't have medical > > > personnel going along, then check with your friendly neighborhood diving > > > doc for some anti inflammatory meds to take with. They can make a big > > > difference in the recovery. > > > Now I'll slip into my asbestos suit and await the flaming. > > > Wendell Grogan > > > > > > > Date: Sun, 13 Feb 2000 10:50:11 GMT > > > > From: Edward Watson <ted.watson@ze*.co*.uk*> > > > > To: Steve Schultz <se2schul@un*.ma*.uw*.ca*> > > > > Subject: Re: In water recompression. (FWD) (FWD) > > > > > > > > <snip legalities bit, not interested in that> > > > > > > > > > The first assumption is that the worst thing the "omitter" has > > > > > effectively done is move up the last 20 feet and out of the water too > > > > > fast. By this I mean that if any of us do this at any point in any deco > > > > > proper or improper, we are foaming out that last pressure gradient that > > > > > NO amount of deco will remove. Only a slow ascent to the surface will > > > > > allow that last bit of gas to come out in solution. Jumping up 20 feet > > > > > will bring it out in bubble form, no matter what. > > > > > > > > > So now the guy is out and foaming, but only the doppler knows this - > > > > > he is asymptomatic. We know from our doppler experience and endless > > > > > studies that this bubbling will actually INCREASE with time after the > > > > > diver is out of the ater, and will peak some 20 minutes to an hour > > > > > later, and hold at that level for up to hours. > > > > So assuming ommitted deco, the idea that the first 30 minutes or so > > > > post dive is effectively a surface deco stop is incorrect, it should > > > > be much longer? > > > > > > > > > Now, we have two choices - do nothing ( which includes breathing > > > > > oxygen on the surface ), or tell him to go back and do some deco , and > > > > > then ascend slowly. > > > > > > > > What do you mean 'some deco'?- just repeat what was omitted exactly, > > > > or go a bit deeper and start again, or add in extra time at the > > > > ommitted stops/faster ascent > > > > > > > > > Now we have to look at the profile - how deep , how long, how > > > > > serious could this omission be? How deep do we have to get this guy to > > > > > reduce the bubbles to where we can get them into solution or at least > > > > > managable enough to offgas through the lungs or get small enough to pass > > > > > by way of the circulatory system to the lungs where we can work on them > > > > > with oxygen. > > > > > > > > > Generally, if you can keep the guy alive, and stay on him, and that > > > > > goes for a may-be-nothing situation to a real blowout, getting him down > > > > > and getting him on oxygen ( or the correct max PPO2 gas for the depth) > > > > > are both a must if he is going to not be brain damaged. > > > > > > > > > The general best bet in the three situations you describe are to > > > > > take your chances by going back in, finding the starting point that is > > > > > reaonable and will not take to long to ascend from, and redoing that > > > > > part of the deco, with special emphasis on taking the last 30 to 20 feet > > > > > very slowly all the way up. > > > > > > > > How do you decide what starting point is reasonable in a given > > > > situation, or is just a best guess thing > > > > > > > > > Pain hits are not so big of a deal as an annoyance and a dive trip > > > > > ruiner as they are not going to go away completely. For one, the bubble > > > > > traped most likely seeded much deeper , and only grew to pain size > > > > > later. You can tell the depth at which it shrinks when the pain goes > > > > > away, and do the math to figure how deep it reasonably cound have seeded > > > > > at. It is a waste of time to go back to that depth since the damage is > > > > > done and you will feel the pain of the damage long after the bubble has > > > > > been reabsorbed. The better bet is to reduce it somewhat and give it a > > > > > chance to diminish ( they generaly grow first, but you have > > > > > receompressed it somewhat) and then try to overcome it with oxygen in > > > > > the slow ascent. > > > > > > > > realistically a pain hit is going to be much easier to sort out in > > > > the field than one involving paralysis etc. What we need to know is > > > > how best to deal with it if there's going to be a reasonable delay in > > > > evacuation to a chamber. Obviously it's always going to be a balance > > > > with hypothermia, gas volumes possibly sea-sickness all being considerations. > > > > > > > > > > > > > > > > -- > > > > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > > > > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > > > > > -- > > > When I die, I want to go peacefully, in my sleep, like my grandfather. > > > Not screaming, like the passengers in his car. > > > -- Jack Handey [Saturday Night Live persona] > > > -- > > > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. > > > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'. > > -- > When I die, I want to go peacefully, in my sleep, like my grandfather. > Not screaming, like the passengers in his car. > -- Jack Handey [Saturday Night Live persona] -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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