Would You Opt For In-Water Recompression?

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 be exhaled.

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 surface.

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 car."

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 hospital-based facility."

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. BenDDavison@undercurrent.org

- Ben Davison

If you're interested in the full in-water recompression protocol recommended by Gilliam, click here.