DCBC, in regards to your response to my post, what sort of safe guards are commercial divers taking that you believe we should also be taking?
Also if you could clarify about the exposures of recreational divers and their risk for bone necrosis. As Sloth pointed out and I originally prefaced, I didn't think osteonecrosis was a concern. Is a 20 minute BT at 300 feet(which happens relatively infrequently for most of us) really enough of an exposure to cause concern with osteonecrosis?
Feel free to PM me as it isn't directly relevant to the thread.
Looking forward to your response.
Thanks,
Tyler
Hi Tyler,
Where do I start? Perhaps by establishing my limited knowledge of this area, in-that I'm not a Hyperbaric Researcher or Physician. If I was, I don't think I could honestly tell you much more other than it's believed that age, physical condition and the number of previous exposures (which are believed to be accumulative) are contributing factors.
As a research diver at the Experimental Diving Unit at the Defence and Civil Institute of Environmental Medicine, I assisted medical experts develop the DCIEM Air tables (in the 70's) and the Helium-Oxygen tables in the late 80's (you don't have to be too bright to be a guinea pig). These ended up replacing the U.S. Navy tables for operational mixed gas diving to 100 M.
I wouldn't be surprised if my diving experiences put me in a wheelchair in the next 10 years. I know commercial and sport divers who have died and others who have been crippled over the years. I'll keep my fingers crossed.
To highlight that there is no right answer to the problem, I'd point to the high number of variances within breathable gas decompression tables. Commercially, each company makes a choice which one they will follow and this is susceptible to change. Even hyperbaric treatment of DCS is not standardized (as noted in my previous post involving the Israeli Hyperbaric Unit).
Regarding the type of safe guards utilized by commercial divers that you should consider; I would only suggest:
1. That you plan your dives well within the limits (I've known many that have pushed the tables). Be realistic about your condition and fat content. I, like many of my recreational counterparts have not retained the body of a Greek god. If you are a SEAL, many of the tables have been designed for you. If not, back off a bit.
2. Have a realistic assessment of the dive plan. Things go wrong and time is absorbtion. Give yourself a cushion.
3. Suggested decompression times are minimum times. More is generally better.
4. Most divers ascend much too quickly. Slow down.
5. Always dive with O2 immediately available and be prepared to treat for shock. Have all the emergency numbers you need and a reliable method of communication.
6. All diving has an element of risk. Breathing mixed gas under pressure increases it. Use good judgement where, when and how you dive. Because you can do a thing doesn't mean you should. Peer pressure is for fools; you make the decision.
You most likely do all these things anyway. As you might have already gathered, I'm not a fan of IWR, but that is a choice you will have to make.
Commercial divers take carefully calculated risks, but if you dove with a good one, you'd think that he always over-plans and iss an old lady when it comes to safety. Diving at 2 to 300 Meters saturated will do that to a guy.
Hope this wasn't too long winded and is of some help. Take care.
There are old divers and bold divers, but no old bold divers.