Every dive you do, whether or not it needs a
staged decompression stop, is a decompression
dive. That's because as you go deeper, your body
is subjected to more water pressure and the gas
you breathe is delivered at that increased pressure.
DCS, as you know, is caused by the nitrogen that
you have inhaled and absorbed into your tissues,
coming out of solution and forming bubbles in
your blood before it re-enters your lungs and can
The treatment for DCS, of course, is to recompress
the diver so that that gas is re-absorbed
and then bring him back out from pressure in
a controlled manner. Breathing oxygen while
recompressing flushes out the offending nitrogen
quicker. While recompression is best conducted in
a hyperbaric chamber, they are often not available
in the remote places we commonly dive. So, recompressing
by re-entering the water is an alternate
treatment -- and a controversial one, at that.
Years ago, John Bantin, Undercurrent's senior
editor, made a serious error during a dive with an
early Inspiration rebreather at Cocos Island. With
no hope of evacuation to the hyperbaric center
36 hours away by boat, he opted for immediate inwater
recompression breathing pure oxygen. He
wrote about the experience in Diver Magazine (UK),
yet was castigated by some readers for deciding
against evacuation. That he suffered no ill effects
afterward did nothing to influence his critics.
Bret Gilliam, the founder of the training agency
SDI/TDI, has given this subject a lot of thought.
He has run hyperbaric treatment facilities and
recompression chambers as early as 1971. When
recently diving in Raja Ampat, he was dismayed at
the operators' lack of planning for such an eventuality.
He wrote to Undercurrent, "Decompression
illness is a statistical inevitability. It will happen
regardless of the relative 'safety' of a dive profile
and the algorithmic model in a dive computer. The important thing is assessing, recognizing the signs
and symptoms, and making a responsible decision
as to the best protocol to get the optimal outcome
for the victim. Obviously, the first choice would
be treatment at a hyperbaric facility with a PVHO
recompression chamber and attendant staff.
"But, treatment is time critical. Delay in recompression
of more than four hours risks permanent
injury that will not be resolved. Diving in remote
diving locations such as Cocos or Raja Ampat
means that evacuation either takes too long or
simply is impossible. If you don't have immediate
access to an evacuation flight, the hard reality is
that treatment where you are is the best option.
"Oxygen and pressure (from depth) are the necessary
components, with trained staff to supervise
the timed process." [Bret makes these recommendations
after 45 years' experience of procedures to
treat patients in the field.] The outcome record,
with prompt recompression and administration of
oxygen, is hugely successful," says Gilliam.
What's involved? To risk oversimplification,
it would mean the symptomatic diver would be
returned to the water (accompanied by another
attentive diver) to a depth of 60 feet (18m) breathing
pure oxygen for two periods of 20 minutes,
punctuated by 5-minute breaks breathing air. He
then ascends very slowly to 33 feet (10m) where he breathes oxygen for 20 minutes. Then, while
breathing pure oxygen, he makes a 30-minute
ascent to the surface. As you can see, there must
be precise control of depths, time and ascent rate,
while keeping the bent diver warm and comfortable.
Further treatment is then carried out on the
Gilliam says that "The ultimate decision should
fall to the patient... who should be fully informed
of the risks and make an informed decision... But
if unreasonable delays due to evacuation are foreseeable,
it is likely that that in-water recompression
treatment is the best route. The choice comes down
to delaying treatment with inevitable repercussions,
or in-water recompression immediately. There's no
easy answer... but for most divers with an understanding
of DCS, the path would be in-water recompression."
Gilliam thinks it would be a good idea if the dive
industry operating in such remote places embraced
the idea of in-water recompression and adopted
protocols to deal with it when needed; however,
"controversy always arises in this discussion. But the
same was true originally with recommendations on
administering surface oxygen, using diving computers,
and breathing nitrox. Most of the cautionary
reactions come from issues of liability and risk management...
not from the likely outcome of in-water treatment. Nothing is perfect. There will always be
a risk. But the reality of a situation is a huge influence
on the practical response."
It is inevitable that some people vociferously
object to Gilliam's views on in-water recompression.
In an exchange on an Internet diving forum
asking for opinions regarding this subject, Iain
Middlebrook, of HSM Engineering Technology
(a supplier and installer of hyperbaric chambers),
proposes that every dive vessel operating in remote
locations be equipped with a transportable twoman
hyperbaric chamber. They would be DAN
approved with "each treatment to be paid for by
DAN insurance carrier for the price of an average
Fully critical of in-water recompression, Middlebrook adds, "Have you any idea how much
it costs to freight a dead body back air cargo?
That's 20 percent of the purchase price of such
a chamber, for starters! Besides, if you continue
with this 'body on a rope' stunt, even I would have
[lawyer] Concannon's number on my speed dial
favorites.†Can you imagine defending this position
in Court of Law?
"Diving at locations such as Cocos Island,
Malpelo, Komodo, Socorro, Truk Lagoon, Bikini
Atoll isn't exactly cheap. The cost of a chamber
would put prices up by around $150 per diver
and the chamber would be paid for within a year.
Medically trained staff is a question, granted, but
a 10-day diver medics course and a satellite phone would cover. Do you have medically trained staff for
your Soap-on-a-Rope diver?"
Of course, outfitting liveaboards and tiny islands
won't happen in our lifetimes. There is no organization
to legislate such, and few if any dive operators
will take on such an expense. A fanciful idea,
it is still a good one. Professor Simon Mitchell, an
experienced technical diver and medical expert,
known for his over-subscribed presentations at dive
conferences, believes a small two-man chamber
would be a welcome sight, and he'd be happy to
see one installed on any vessel he was diving from
in a remote location.
That said, he adds a valid point: "You would
probably find that DAN would be just as worried
about who was running the show as the chamber
itself. Which leads me to point out that establishing
and maintaining an appropriately trained crew and
maintenance staff would be very expensive. . . .
"I have participated in four Bikini Atoll expeditions
where we have occasionally used the chamber
on board, and occasionally used in-water recompression,
too. No one in their right mind would initiate
a Table 4 (6 ATA) in a two-man chamber on a
boat. Indeed, in this modern day and age, it would
be incredibly rare to find one done in a comprehensive
So, my fellow divers. What do you think? If you
had a bends hit after surfacing from a dive in a
remote location where it would take untold hours
to reach a chamber, would you opt for in-water
recompression, assuming the dive operator knew
the rules? We'd like to hear your point of view.
- Ben Davison
If you're interested in the full in-water recompression
protocol recommended by Gilliam, click