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

[Searcaigh]

You need to know what to do and be trained in the procedure of IWR as well as having sufficient gas, sufficient kit (e.g. FFM), knowledgeable back up crew and favourable weather conditions and exposure protection before even thinking of putting a diver back in the water.

 

[Akimbo]

You need to know what to do and be trained in the procedure of IWR as well as having sufficient gas, sufficient kit (e.g. FFM), knowledgeable back up crew and favourable weather conditions and exposure protection before even thinking of putting a diver back in the water.

That's only true if you want to survive and recover from IWR.

(concurring with Searcaigh)
Seriously, IWR can be a life saver when well executed. It can also transform someone that might survive the bends with a disability into a corpse when done poorly.

 

[rjack321]

That's only true if you want to survive and recover from IWR.

(concurring with Searcaigh)
Seriously, IWR can be a life saver when well executed. It can also transform someone that might survive the bends with a disability into a corpse when done poorly.

Although as Dr. Pyle's reporting illustrated, the number of patients improved by IWR (many) outnumbers those who got worse (at the time there weren't any).

 

[Akimbo]

... Seriously, IWR can be a life saver when well executed. It can also transform someone that might survive the bends with a disability into a corpse when done poorly.

Although as Dr. Pyle's reporting illustrated, the number of patients improved by IWR (many) outnumbers those who got worse (at the time there weren't any).

Agreed. I hope the takeaway from my post is it is important to do IWR well. Doing it well isn't trivial but isn't brain surgery either.

 

[Celt]

i personally recompress divers in the water on 3 different occasions, i believe 2 would have died without emergence recompression, all 3 were conscious and coherent. unfortunately they all became ill within 3 hours and ended up in a chamber. 2 were uncontrolled assents from 58 meters.

 

[Kevrumbo]

Although as Dr. Pyle's reporting illustrated, the number of patients improved by IWR (many) outnumbers those who got worse (at the time there weren't any).

TABLE 1

527 IN-WATER RECOMPRESSIONS IN HAWAII

Complete resolution of symptoms: 462

Residual symptoms but no further treatment sought
as symptoms disappeared within a few days: 51

Residual symptoms needing further treatment: 14

Divers made worse by in-water recompression: 0

Total: 527

Compiled from:
Farm FP Jr, Hayashi EM and Beckman EL. Diving and decompression sickness treatment practices among Hawaii’s diving fishermen. Sea Grant Technical Paper UNIHI-SEAGRANT-TP-86-01. Honolulu, Hawaii: University of Hawaii Sea Grant College Program, 1986

Comment from Pyle and Youngblood (1997) on Table 1 quote above:
. . .From the cases described above, it should be evident that IWR has almost certainly been of benefit to some DCS victims in certain circumstances. If the selection of cases seems biased towards "successful" attempts at IWR, it is only a reflection of the numbers of actual cases on record (Table 1). . .
In-water Recompression as an Emergency Field Treatment of Decompression Illness

 

[Kevrumbo]

Goals of Oxygen Therapy in suspected DCS Syndrome case:
-Bubble Resolution through Denitrogenation (bubble contents almost pure nitrogen given Air/Nitrox bottom gas blend; and/or Helium given bottom gas Trimix).
-Surround bubble with high oxygen environment
-Diffuse Nitrogen out of bubble into blood.
-Nitrogen transported to the lungs and exhaled.

Augmented with IWR for simple type I DCS only, goals are:
-Pain alleviation with Bubble size reduction.
-Best compromise oxygenation of hypoxic tissues and reduction of tissue edema with regard to Oxygen Toxicity risk factors at no deeper than 9msw/30fsw (1.9ATA).

Bubble size Reduction:
-Best compromise treatment at 1.9ATA on Oxygen, with theoretical reduction at 80% of Original Pathological Bubble Diameter (or 20% decrease in occluding or impingement size).

For reference, standard chamber Hyperbaric Oxygen Therapy (HBOT) at 2.8ATA: bubble size reduction is at 70% (or 30% decrease in occluding size). And at 6ATA breathing Nitrox50 or Heliox 50/50 (ppO2 is 3.0 bar max) for AGE: critical bubble size reduction at 55% (or vital 45% decrease in stroke-causing occluding size).

Some more thoughts and experience on O2 IWR:

It's more a dilemma and at worst case, a draconian choice.

If the pain is so acute and intractable despite surface O2 and analgesics, a type I DCS patient is going to insist on Oxygen IWR given that the dive-op has the necessary equipment and gas supply. The practical reality is unless there is a physician available at this remote site who can provide an opiate pain-killer injection, you're not going to convince the patient to "take the pain" and waiting endless hours for evacuation & transport to a proper hyperbaric facility.

For more serious and acute type II, pulmonary DCS and near drowning AGE, all you can do is provide palliative treatment while awaiting transport to a "frontier" emergency Advanced Cardiac Life Support (ACLS) and hyperbaric medical clinic.

I believe it's just as much a controversial medico-legal issue as well -which is why no hyperbaric physicians are responding to this thread as of yet, nor do I think there will be a consensus agreement -let alone a full endorsement- on use of O2 IWR by DAN or the UHMS Adjunctive Treatment Committee.

It will be IMO officially stipulated as elective and optional treatment AMA ("Against Medical Advice"), and signed off as such if a Hyperbaric Physician happens to be involved in a particular case -especially if the case goes bad (i.e. Oxygen Toxicity Seizures at depth)- given the decision to undergo O2 IWR by the patient or persons acting on behalf of the patient.

Otherwise if your team is isolated & alone, but prepared, trained and has the necessary proper equipment & Air/O2 gas supply to handle DCS -good luck & go for it.

 

[Kevrumbo]

For the traveling tropical tech diver overseas, you need at minimum a dive operation that can at least supply 100% O2 and Air in separate Aluminum 11L cylinders (you may have to bring your own FFM); and a shallow lagoon or clear boat-dock space with a firm sandy bottom at 9msw/30fsw to lie prone on.

You need a wetsuit or drysuit undergarment heater system as well.
Even in 80°F/27°C tropical waters, you will get chilled after more than an hour, which can also impact efficacy of the treatment. (Especially the last 135 minutes on the slow ascent to the surface from 9msw of the modified Australian O2 IWR method. It was nice to flip the switch and have heat on demand under my skinsuit. . .)

There are two versions of "modified" Australian O2 IWR Therapy:
(I)
The modified Australian IWR Method as taught by UTD has either 30, 60 or 90min choice of prescribed O2 breathing therapy at 9m/30ft depth (10min O2:with a 5min Air Break); and then a very slow 0.1 meter-per-minute (0.3 feet-per-minute) ascent to surface breathing 10min on O2 with 5min Air Break.

So choosing 60 minutes of O2 time at 9m for example, you breathe 10min on Oxygen, and then take a 5min break on Air for a total bottom time of 90 minutes (Air Breaks add to the total bottom time and do not count or accrue credit into the O2 time at 9m), and on the slow 0.1mpm O2 breathing ascent you have to hold at depth after every 1 meter of ascent for the 5min Air Break, before starting again the 0.1mpm O2 breathing ascent –a total time to surface of 135 minutes. So the total treatment time would be 90min bottom plus 135min ascent equals 225 minutes. Can be done with an AL80/11L cylinder of Oxygen and another of Air on Open Circuit. . .

(II)
(R. Walker in Carl Edmonds' Diving and Subaquatic Medicine)
Descend to 9m
Breathe O2 for 30-90min depending on symptoms, take an airbreak every 25min

Ascend to 8m at 1 m every 12min
Ascend to 7m at 1 m every 12min
Ascend to 6m at 1 m every 12
Ascend to 5m at 1 m every 12
Ascend to 4m at 1 m every 12
Ascend to 3m at 1 m every 12
Ascend to 2m at 1 m every 12
Ascend to 1m at 1 m every 12
Ascend to surface , breathe O2 for 1hr then 1 hour off for a further 12 hrs, intermingled with fluids.

Notes:
Run time of 138-208 min depending on time at 9m + the additional 6hrs on surface of oxygen

If no full face mask available then
do not exceed 6m on O2, to get a PO2 of 1.6 for 30 min
Then ascend to 5m in 12 minutes and remain at 5m for 30-60min

Ascend to 3m in 15minutes and resume above schedule.

 

[rjack321]

TABLE 1

527 IN-WATER RECOMPRESSIONS IN HAWAII

Complete resolution of symptoms: 462

Residual symptoms but no further treatment sought
as symptoms disappeared within a few days: 51

Residual symptoms needing further treatment: 14

Divers made worse by in-water recompression: 0

Total: 527

Compiled from:
Farm FP Jr, Hayashi EM and Beckman EL. Diving and decompression sickness treatment practices among Hawaii’s diving fishermen. Sea Grant Technical Paper UNIHI-SEAGRANT-TP-86-01. Honolulu, Hawaii: University of Hawaii Sea Grant College Program, 1986

Comment from Pyle and Youngblood (1997) on Table 1 quote above:
. . .From the cases described above, it should be evident that IWR has almost certainly been of benefit to some DCS victims in certain circumstances. If the selection of cases seems biased towards "successful" attempts at IWR, it is only a reflection of the numbers of actual cases on record (Table 1). . .
In-water Recompression as an Emergency Field Treatment of Decompression Illness

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.

I'm usually prepared to get back in the water for a short time (e.g. 30mins on O2 or high fO2 CCR) to at least mediate symptoms. It gets more complicated when the water is seriously hypothermia inducing (<50F) and suits floods may have potentiated the DCS in the first place.

 

[Akimbo]

I'm usually prepared to get back in the water for a short time (e.g. 30mins on O2 or high fO2 CCR) to at least mediate symptoms. It gets more complicated when the water is seriously hypothermia inducing (<50F) and suits floods may have potentiated the DCS in the first place.

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?