Originally Posted by
rchrds
Hmmm interesting. Some of you know how I dive, most dont, and really, saying one has been bent without some intimate knowledge of how that diver conducts dives really doesn't help other people that much. I have been bent only once, perhaps twice (mild skin bends on the second time) which is pretty good for the diving that I do. Neither resulted in a chamber ride (no CNS symptoms) both were treated with hydration, aspirin and oxygen, and a couple days off diving. The one chamber ride I have made had no DCS symptoms prior or post, and was the result of a deep water hyperoxic seizure, and conservative doctors. (no complaints.)
But how about the two incidents? Neither exhibited symptoms in water.
At the time, I was mid-late 20s, 5'10" 170 lbs, athletic build, running every other day and diving at least every third day on a constant basis. Always diving every day over long weekends. Rarely more than one dive per day.
Almost all dives (particularly the ones in question) are Florida caves, most of them in the 130-230 foot range, an occasional one in the 300 range on weekends, and rarely the shallow river dive less than 100. No dives less than an hour, most 2-3 hours and 8+ hours was not uncommon.
Mixed gas was the standard, 1.2-1.4 swimming, 1.6 deco. Almost always swimming, very rarely scootering. (Didn't have scooters in those days, had to borrow from my rich friends!)
All tables cut and stored on wetnotes with whatever program was in vogue at the time, but mostly GAP and then something before that, but I cant remember the name. Until very recently I did not use a computer for deco, and even still, I dont really like using the computer for deco, as I have a Vr3 that produces retarded numbers, and I hate it.
So how did I get bent? Many of the locations that I dove required that tanks be hauled down a steep embankment at a sinkhole to get to the water. There were never steps, so it was either haul them up one at a time (sidemount) or put them on a rope and haul away. Either way, it was quite a lot of work both before and after the dive.
On the dives in question, in both cases, the dive was approaching 3 hours, at a depth range of somewhere in the 150-180 range. I completed deco feeling fine, and made a good surface rest period while the mosquitos tore me up. I knew the tanks had to be hauled up the hill, and it was not going to be pretty. I was right, it was not pretty, and I got out of breath very rapidly hauling each tank up the hill, which for me, is a sure sign that I have worked too hard after deco and I am flirting with getting bent. Unfortunately, I had places to be, and could not wait a long period between hauls, and after carrying 6 bottles up the hill, I got back in the kidnapper van and drove back to gainesville. Sure enough, one shoulder and elbow was killing me soon after, which I self medicated.
Did I see it coming? Sure. Was it deserved? Sure. Could I have prevented it? Perhaps, if I had taken my time, and had all afternoon to lounge in the sun, or had friends who like to carry tanks.
I am of the opinion that there are no "underserved hits." Most of the time, you just do something that you either fail to remember after the fact, or most likely don't even recognize as something that is going to cause an event later on, and then are surprised when you end up in the chamber.
A friend and often dive buddy from those days dove frequently with the KPP back before that was such an internet sensation, and would come back almost weekly with some level or another of DCS. This was before DAN had imposed their limits on chamber rides (they used to pay as many times as you could go) and he probably went to the chamber 5 times that I can remember. But it was the last time, when he almost died in the Shands parking lot after being revived by a passing paramedic following his 2 hour drive from Tally, puking all the way, that finally stopped his cave diving. What was he doing wrong? I still suspect that he had a PFO. This was before the days when that was commonly identified as suspect, or was in fact even a well known problem among divers. He continued to dive very deep profiles using deco software that was pretty similar to what we use now- But nobody else would get bent on the same dives. He began seriously padding his shallow stops. It didn't help.
While I am on the topic, I have another friend, which some may also know that seems to get bent pretty regularly. Almost all of his dives are in two or three caves, all in the 130-180 range, sometimes on He, sometimes not, but all very long dives, usually 3-5 or longer. He is extremely athletic (marathons and such) and does not have a PFO. Yet, he still gets bent. Why? I have a theory. Of course, the thinking is that once you have been bent badly, you have a serious risk of a recurring event. This individual has never gone to the chamber. To the extent that we have threatened to take him there ourselves, he is averse to either going or paying, not sure which. Probably he has burned out his DAN already, and is on his own dime, which would not surprise me. Regardless, his answer is sleep, ****loads of aspirin and water, and all the oxygen you can get in the car. Now, he gets bent easily. Dives that nobody even gets twinges on, he will get mild symptoms. Does that stop him? No, but it is his body.
So for the new guys asking how is it that all these cave divers are getting bent? I think that you would find that the majority are NOT getting bent- And I would venture that most are not getting bent because the vast majority that go to Ginnie, Peacock, Manatee and the like are not getting far enough into their deco obligations that they run the risk of being bent every dive. Our computers and some tables are still padded, and there is always some inherent conservatism in your software (there are some notable exceptions) but for the vast majority, a dive where you have 20 minutes of O2 at 20 feet is not going to produce serious symptoms if you do something stupid like bounce up, or ascend to fast. This coupled with the fact that basic cave diving instruction these days is pretty good at building an understanding of how to manage simple decompression, and how to identify the stupid things you shouldnt do that are sure to get you bent.
Where you see the anomalies are the exploration dives- the dives where people are spending long hours in the water and building up significant decompression profiles- with ceilings that start below 50 feet or so. At those obligations and worse, errors in judgement at depth (rapid ascent, skipping a stop) can have consequences later in the decompression that simple time at depth is not going to fix.
It is worth it to reiterate a belief from other sources that the real danger zone is 130-180 feet of depth. I completely support this belief, as it is in this range that the decompression ceilings really start to gain depth quickly, and frequently, people do not bother to plan the correct decompression, or carry the correct gasses to execute a safe decompression. It is in that range where you say "Dang, it isn't that deep, I'll just take O2, and hang a little longer, it's not like it's 300 feet or something." So perhaps a relaxed approach to a dive that is really technical, but not being treated that way.
This has already gone on too long, but something to think about.
jason
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