What I have wondered about is doing underwater recompression if there were no other option available in a case where symptoms of DCS were present.
Tjack: Let's attempt to clarify the issue of IWR. 1) It's risky. Those risks include those mentioned in my earlier post with a strong emphasis on the subject diver getting worse... becoming paralysed for example... and/or loosing consciousness. Oh, and dying.
Various protocols and tables for IWR have been developed over the years. The recognized tables include the Australian, the US Navy, and the Pyle tables... I believe Pyle's modification to the Hawaiian table are the most "up-to-date." I am reasonably sure that NONE carry sanction from the major sport agencies and therefore the only recommended treatment for a sport diver is to alert EMS, give surface oxygen, hydration, close supervision and evacuation at first opportunity.
The technical agency I teach for, I do consultant work for and on whose training advisory panel I served for several years, does not sanction IWR either. I hope that's clear. Essentially, and especially in the context of the OP's original question, IWR is simply NOT an option, for ANY recreational diver (sport or tech) and especially NOT in the situation described.
Now, just in case it's not clear why, here's a checklist of the minimum kit and personnel requirements for attempting IWR in a remote location.
- a heavily weighted shot line secured in a sheltered spot where surface waves will not influence comfort of subject diver and/or the tender (who will be in the water) and treatment supervisor (who will be on the surface).
- Some way to hold the subject diver in place... a climbing harness works as does a sidemount harness with some modifications
- Stages in the shot line to hold the subject diver at a set position in the water column... prussik loops work if done correctly
- Full-face masks with coms to the surface and each other
- Surface supplied gas (oxygen et al) supplied to the subject diver via umbilical
- An experienced tender and supervisor who have at very least certification and some background in hyperbaric treatment
- A valid IWR treatment "table"
As someone who is occasionally involved in expedition diving (the only situation I can imagine where the whole team would discuss IWR as part of the SOPs during pre-trip planning sessions), IWR is considered highly risky even when ALL the above, and a few more details, are available. It is also understood that IWR (just as recompression in a chamber on the deck of a boat or in a medical facility) may not resolve the issue. In other words, the subject diver may die.
The preferred option if a portable chamber is NOT AVAILABLE -- and something many expedition leaders seem to have less hesitation using -- is
saline IV therapy, oxygen and the use of pain medication all administered by a practicing medical practitioner of some sort... NP, Paramedic, MD et al. It is therefore considered best practice to have at least one of these as part of the team on ALL expeditions to remote locations... I invite someone with this background on ALL expeditions and am lucky enough to have been team leader on expeditions on which our medical team was very experienced. To date, these staff have supervised a diver autopsy but have NOT been called on to help with IWR, therefore my first-hand experience with this issue has been ZERO.
The protocols for MISSED or OMITTED DECOMPRESSION are different because the circumstances are totally different and are discussed and outlined in several technical diving student manuals... including a couple of TDI manuals. The procedure is based on the one once used by the US Navy and which can be found with a Google search.That procedure is taught as part of decompression and trimix courses. It is NOT offered as an option nor is it taught to North American sport divers, because it is outside the scope of sport diving parameters. The scenario originally presented in this thread is one that I believe falls into the accidental muppetry of a sport diving incident, and therefore, my original suggestion stands... it's risky, don't attempt it. My later edit (and for those who may wonder about that edit, nothing was changed in the body of my reply, certainly not the tone of my response) simply added a suggestion to purchase Mark's excellent book. Which I also stand by.
For what it's worth, I have tendered for divers who have missed decompression and for whom the omitted deco protocol worked.
Hope this helps to clarify the whole issue.
