In-water recompression to decompress - what are your thoughts?

[rjack321]

Jumping back in with a stage bottle and a sore shoulder while hanging at 15-20' (4.5-6M) isn't cause for a lot of hand ringing or team participation. However less ambiguous symptoms and dropping to 30' (10M) is another issue. How bent do you think you are and how aggressive do you need to be over treatment?

I haven't really had to make that choice when overt neurological type 1 symptoms are present. At least in my circumstances we are prepared for ~30-45mins of extra IWR deco on O2. This could be stretched to perhaps an hour depending on the dive profile/site/weather/hypothermia/symptoms/other extenuating circumstances. Bringing resources for a full on IWR effort isn't really appropriate if the patient would freeze before finishing. So we treat it as a tool to moderate symptoms and buy time for what is likely to be a long travel to advanced care. Dive site to EMS might be many hours (6?) and time to the chamber door closing is likely 20 to 40hrs.

 

[Kevrumbo]

This reference is over 22 years old however. With the more extensive use of IWR (in part because of this exact paper) there may very well be divers who toxed, died or otherwise were an IWR failure. Hard to know. . .

We really don't have anything more objective or current than Pyle/Youngblood's and Carl Edmonds' original articles on IWR anecdotal case studies from the South Pacific Underwater Medical Society (SPUMS) Journal (IN-WATER RECOMPRESSION AS AN EMERGENCY FIELD TREATMENT OF DECOMPRESSION ILLNESS and Underwater Oxygen Treatment of Decompression Sickness: A Review ); and a UHMS IWR Workshop -all twenty years ago or older, so looking forward to David Doolette Ph.D's IWR presentation and @Dr Simon Mitchell's attendance at this weekend's April TekDiveUSA conference, as well as prelim updates on their own workshop/conference back in 2004: (Management of Mild or Marginal Decompression Illness in Remote Locations).

I haven't really had to make that choice when overt neurological type 1 symptoms are present. At least in my circumstances we are prepared for ~30-45mins of extra IWR deco on O2. This could be stretched to perhaps an hour depending on the dive profile/site/weather/hypothermia/symptoms/other extenuating circumstances. Bringing resources for a full on IWR effort isn't really appropriate if the patient would freeze before finishing. So we treat it as a tool to moderate symptoms and buy time for what is likely to be a long travel to advanced care. Dive site to EMS might be many hours (6?) and time to the chamber door closing is likely 20 to 40hrs.

FWIW, unless you or a teammate have an unknown PFO condition, or unfortunately suffer very rare pathologies like Pulmonary "Chokes" and/or Immersion Pulmonary Edema; the only likely DCS milieu IMHO you have to worry about and be prepared for as necessary with elective O2 IWR is essential type I DCS pain only/non-acute neuro symptoms of "unknown/unexpected cause", status post completed mandatory decompression dive with a seemingly "properly planned deco scheduled profile." (The so-called "undeserved hit")

IOW, something extremely catastrophic beyond your control precipitating an acute neurological DCS type II paraplegia, or emergency near drowning AGE event would have had to occur (i.g. Aborted Deco Schedule forcing an immediate rapid ascent).

 

[rjack321]

FWIW, unless you or a teammate have an unknown PFO condition, or unfortunately suffer very rare pathologies like Pulmonary "Chokes" and/or Immersion Pulmonary Edema; the only likely DCS milieu IMHO you have to worry about and be prepared for as necessary with elective O2 IWR is essential type I DCS pain only/non-acute neuro symptoms of "unknown/unexpected cause", status post completed mandatory decompression dive with a seemingly "properly planned deco scheduled profile." (The so-called "undeserved hit")

IOW, something extremely catastrophic beyond your control precipitating an acute neurological DCS type II paraplegia, or emergency near drowning AGE event would have had to occur (i.g. Aborted Deco Schedule forcing an immediate rapid ascent).

And cardiac events, pulmonary embolism, stroke and a myriad of other possible causes - all of which might actually be good reasons to NOT get back in the water. But that said, most people I know, myself included - if presenting with symptoms almost immediately on surfacing - will go back down for more time. If the symptoms resolve or attenuate at 20ft they know that they are likely on the right track. 20ft on OC O2, probably dropping a little deeper on CCR, 30-35ft with a ppO2 of ~1.4+.

Once time has passed, the tanks have been removed, drysuits removed, boat is on its way home etc. The choice to re-enter the (cold) water in lieu of getting to EMS immediately is most complicated.

 

[Kevrumbo]

. . .But that said, most people I know, myself included - if presenting with symptoms almost immediately on surfacing - will go back down for more time. If the symptoms resolve or attenuate at 20ft they know that they are likely on the right track. 20ft on OC O2, probably dropping a little deeper on CCR, 30-35ft with a ppO2 of ~1.4+.

Once time has passed, the tanks have been removed, drysuits removed, boat is on its way home etc. The choice to re-enter the (cold) water in lieu of getting to EMS immediately is most complicated.

. . .Bringing resources for a full on IWR effort isn't really appropriate if the patient would freeze before finishing. So we treat it as a tool to moderate symptoms and buy time for what is likely to be a long travel to advanced care. Dive site to EMS might be many hours (6?) and time to the chamber door closing is likely 20 to 40hrs.

We're lucky and take for granted for what we have in support of offshore Southern California Diving, in that we don't have to face that dilemma.

Resident and visiting divers alike always have a 6ATA capable double/auxiliary lock multiplace Recompression Chamber and facility with Advanced Cardiac Life Support utility that's strategically located for diving emergency triage either minutes away from the closest popular divesites, to at most 90 minutes ETA from divesites nearly 130 nautical miles away via USCG rotary wing. And always available on 24/7 & 365 days stand-by as part of the local Los Angeles county government EMS/Lifeguard/Fire and Sheriff's SAR teams, whether you have primary health insurance coverage -or as in the case of an indigent sea urchin harvester/diver for example- no insurance whatsoever. There's even no need to call DAN for consultation or pre-approval to start HBOT until long after the treatment is completed to settle any covered insurance reimbursement.

IWR is never a last resort or even an elective option here in Southern California, because all DCI cases with morbidity from simple type I DCS to acute near drowning AGE can be treated at an island 6ATA recompression chamber reserved only for the emergency treatment of diving accident casualties (and two more mainland 6ATA capable multiplace chambers as back-up at Univ of Calif Medical Centers in Los Angeles and San Diego). After going through four separate overseas O2 IWR contingencies, I now fully appreciate the health and welfare support available to all divers here in my SoCal homewaters. . .

 

[Michael Guerrero]

For those reading this thread, the Navy schedule is 60 min, 60 min, 60 min at 30ft, 20ft, 10ft for Type 1 and 90, 60, 60 for Type II. Take air breaks at a 2:1 O2:air ratio. Other recommendations in the manual.

Two or three AL80s of O2 (RMV dependent) and an AL80 of air should work.

 

[Searcaigh]

Two or three AL80s of O2 (RMV dependent) and an AL80 of air should work.

Plus enough gas for any support divers

 

[rjack321]

Plus enough gas for any support divers

Plus a FFM or a habitat

Especially if you already did a deco dive that's a ton of CNS

 

[Akimbo]

Plus a FFM or a habitat

I have a lot of experience with habitats. There are a lot more logistics problems with them than most people can imagine. By the time everything is considered it is easier, more effective, and less expensive to just have a chamber like this onboard.

 

[drbill]

All the evidence I have seen on her death indicates that although she was attempting to deal with an omitted decompression issue, her death was due to a combination of being OOA and technical problems and had nothing to do with DCS. She had no air in her own tank and redescended holding (not wearing) another BCD and tank, with that other BCD being her only means of achieving buoyancy. She apparently lost her grip on that, and a technical problem prevented her from ditching her own weight.

Thanks for the additional clarification of the events following Mia's submergence. I was not aware of all the details.

Perhaps I am missing the accepted definition of IWR. To me Mia's incident was an attempt to avoid DCS by resubmersion which in my mind qualifies as an attempt at IWR but if the term only applies to those already experiencing DCS then I was wrong. I'm a marine biologist rather than a SCUBA pro.

 

[boulderjohn]

Perhaps I am missing the accepted definition of IWR. To me Mia's incident was an attempt to avoid DCS by resubmersion which in my mind qualifies as an attempt at IWR but if the term only applies to those already experiencing DCS then I was wrong. I'm a marine biologist rather than a SCUBA pro.

Your new understanding is correct. The term IWR only applies to measure taken for divers who are already showing symptoms of DCS. As this thread indicates, it is a controversial procedure. Redescending quickly to complete a missed stop while showing no signs of DCS is called omitted decompression, and it is usually considered a routine procedure.