Mailing List Archive Mailing List Archive
>From: Richard Pyle <deepreef@bi*.bi*.Ha*.Or*> > >> An interesting feature might be the capability to handle missed deco in a >> more constructive way than current computers (lock off for 24 hours). The >> computer could probably tell you exactly how to perform IWR based on >> bubble growth during the time you were at the surface. It should also be >> able to give you an air version of IWR. > >Years ago, when I first heard of the Quatek ACE ProFiler (I think that's >what it was called) dive computer - a mixed-gas programmable >decompression computer, I wrote Kevin Gurr and suggested this exact >thing. We decided it was unfeasible for two reasons: > >1) Liability (it'll get you EVERY time!), and >2) We know soooo little about IWR that we wouldn't even know where to >begin in terms of developing a model. The thing I had in mind is that the bubble models can continue to estimate free gas phase growth after surfacing and hence should be able to tell you how to get rid of the free gas phase. This is at least part of the reason for IWR. The other part of recompression therapy, as I understand it, is to assist in repairing the damage caused by the bubbles. This would certainly be a big unknown in terms of modelling. The case I am primarily thinking of is not so much treating symptomatic bends, but rather the case of being unable to complete deco for some reason and needing to do a missed-deco procedure. These are reasonably well established for things like USN air tables, but when you move into mixed gas, what do you do ? Most dive computers today will simply lock up if you miss deco, whereas, a bubble model computer could give you enough info to find a fresh gas source and get back in. It could probably also give you an estimate of when after surfacing to start expecting symptoms to develop!!!! > >Perhaps a more realistic first-step is to work out an IWR flow-chart that >accounts for three or four different dive variables, that suggests one of >maybe three or four different IWR protocols (how much surface O2 before >going to IWR, whether or not to add a deep nitrox "spike" and for how deep >and how long, etc.) I've suggested this to Eric Maiken, who might be >able to come up with some physics-based ideal IWR profile for various >sets of factors, but neither of us has had much time to think about it >long and hard enough. Anyway, I think that sort of thing might be a >first-step towards developing a model. Sounds an excellent idea. I am very interested in alternatives to full IWR protocols as a first aid device prior to definitive chamber treatment. > >The problem with IWR is that it's almost impossible to do controlled >studies on it. The only way to learn anything meaningful is to examine >hundreds of anecdotal cases. Unfortunately, not that many people are >doing it, or if they are, they're not recording many details. I suppose >we could learn a little bit about it by bending defenseless little furry >animals and seeing how they respond with immediate recompression in a >chamber...but who's got the bucks? Sounds like a good PhD project. Maybe one of the experts in this field might like to get a student onto it (do you know Yount ? Or maybe Van Liew might be interested). I am looking forward to reading your article in Aquacorps when it finally arrives, it seems to take about 6 weeks for them to get to us (Whoops, I just realised I admitted to subscribing - I think it has recently become rather not PC! For what it's worth, I don't like the direction the magazine has taken and am likely to swap my subscription to something else when it comes up for renewal). Cheers, David. ______________________________________________________________________________ David Giddy, Voice: +61 3 9253 6388 Telstra Research Laboratories, Fax: +61 3 9253 6144 P.O. Box 249, Rosebank MDC, 3169, AUSTRALIA Email: d.giddy@tr*.te*.co*.au* ------------------------------------------------------------------------------
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]