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Scuba Forum / General / July 2005Come again?
Unless I have totally forgotten the concept of Boyle's Law, does this make any sense? "Two days after a dive, a 31-year-old- male walked into a Louisiana hospital ER agitated, with delusions, paranoia, and complex visual hallucinations ... While scuba diving, the patient had made a breath-holding ascent from 45 feet to 15 feet ... " That dude must have some pretty pliable lungs. Buck > Unless I have totally forgotten the concept of Boyle's Law, does this make > any sense? [quoted text clipped - 5 lines] > > That dude must have some pretty pliable lungs. 45 feet is 2.36 ATA, or 33.276 PSI. 15 feet is 1.45, or 20.445 PSI http://www.scubamed.com/feature.htm Lung overpressure injury can occur from as little as 4 feet of depth because of the Boyle's law relationship: P V = K, which states the the product of absolute pressure and volume is a constant. As pressure falls on ascent, the lung volume expands. This diagram shows the percent change in lung volume for 10 foot changes in depth from 100 feet to the surface. Note that there is a 32.7% change in volume when ascending from 10 feet to the surface, while the change in volume when going from 100 to 90 feet is only 2%. So, inhale compressed air at 4 feet, hold it, and then ascend to the surface, and you risk a barotrauma injury. If they held their breath from 45 to 15 feet, I'd say its highly likely they suffered lung injury. > Buck Dennis > If they held their breath from 45 to 15 feet, I'd say its highly likely they > suffered lung injury. Sure, but would it take 2 days to notice it? >> If they held their breath from 45 to 15 feet, I'd say its highly likely >they >> suffered lung injury. > >Sure, but would it take 2 days to notice it? If I'd been dead for two days, I'd certainly feel at least a little paranoid about the whole thing. I doubt that a) he really did that stupid stunt and 2) mushrooms can cause those sorts of symptoms. More likely the brown acid.  Signaturedillon Linux, it's not just an OS, it's a way of life. And a damn fine one, at that. > >> If they held their breath from 45 to 15 feet, I'd say its highly likely > >they [quoted text clipped - 7 lines] > I doubt that a) he really did that stupid stunt and 2) mushrooms can > cause those sorts of symptoms. More likely the brown acid. Well, they did say he was having delusions. > If they held their breath from 45 to 15 feet, I'd say its highly likely > they > suffered lung injury. Kind of depends on how full the lungs were at the beginning of the ascent, doesn't it? An OOA diver usually discovers the problem after he's exhaled. At that point, he has little gas in his lungs and should have no significant problems as a result of holding his breath from 45 feett, all the way to the surface. Personally, I'm more likely to damage my ears than my lungs. I sometimes have problems with reverse blockage. Lee >> If they held their breath from 45 to 15 feet, I'd say its highly likely >> they suffered lung injury. > >Kind of depends on how full the lungs were at the beginning of the ascent, >doesn't it? ... No, it doesn't! If you don't believe it you're welcome to try it <grin>, but I assure you that no body can empty their lungs enough to survive a breath holding ascent from 45 to 15 feet. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. >>>If they held their breath from 45 to 15 feet, I'd say its highly likely >>>they suffered lung injury. [quoted text clipped - 7 lines] > that no body can empty their lungs enough to survive a breath holding ascent > from 45 to 15 feet. A little math: Breath out to residual capacity typical 1,5l. Ascend to depth of a 1/1,6 of pressure, give a lung volume of 2,43 l. Nothing to worry about, and leaves enough margin for not exhaling fully. Matthias hammond@not wrote: > >> If they held their breath from 45 to 15 feet, I'd say its highly likely > >> they suffered lung injury. [quoted text clipped - 7 lines] > that no body can empty their lungs enough to survive a breath holding ascent > from 45 to 15 feet. Really? I can do it: Fill lungs on surface. Hold breath. Dive to 45 feet. Continue to hold breath. Ascend to 15 feet. My guess is that I'd still be alive. Then back to surface. Cheers, Froggy >>>It kind of depends on how full the lungs were at the beginning of the >>>ascent, >>>doesn't it? ... >> No, it doesn't! Yes, it does. >> If you don't believe it you're welcome to try it <grin>, but I assure you >> that no body can empty their lungs enough to survive a breath holding >> ascent >> from 45 to 15 feet. No problem. You an assure anybody of anything you like, but you're still wrong. Froggy's example below makes it pretty clear that it is not only possible, but easy. > Really? > [quoted text clipped - 13 lines] > > Then back to surface. > >>>It kind of depends on how full the lungs were at the beginning of the > >>>ascent, [quoted text clipped - 12 lines] > wrong. Froggy's example below makes it pretty clear that it is not only > possible, but easy. How about filling your lungs at 45 from your scuba gas supply, then hold your breath & ascend to 15 feet. Dennis > > Really? > > [quoted text clipped - 13 lines] > > > > Then back to surface. > > >>>It kind of depends on how full the lungs were at the beginning of the > > >>>ascent, [quoted text clipped - 18 lines] > > Dennis Filling your lungs at 45 wasn't exactly the issue under question... the issue was whether or not you could "empty" your lungs enough to make the 45'-15' breath holding ascent without damage. of course you would be alive....freediving? Why are you all having this conversation? What I think you may have wanted him to do is : Hold breath to 45ft.....take in air from regulator at 45ft...then hold that breath and surface....make sure you hold that entire breath at FULL lung capacity.......note: I'm not responsible for anyone's death or sick-ness....unquote.....:) What will happen?- Per your lungs are 100% maxed....when you rise your LUNGS will expand per the pressure ON YOUR LUNGS (at 45ft) will be no more....this means you will end up with Lung Over Expansion..............*** SEE Dictionary *** >>>>It kind of depends on how full the lungs were at the beginning of the >>>>ascent, [quoted text clipped - 31 lines] >> >> Then back to surface. > Unless I have totally forgotten the concept of Boyle's Law, does this make > any sense? Yeah, it's the diving equivalent to - if a chicken and a half lays an egg and a half in a day and a half how long will it take .... |
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