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February 2017    Download the Entire Issue (PDF) Available to the Public Vol. 43, No. 2   RSS Feed for Undercurrent Issues
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In-Water Recompression? Our Readers React

from the February, 2017 issue of Undercurrent   Subscribe Now

Undercurrent asked, in January, if you were exhibiting symptoms of decompression illness, but were at a remote location (as we often are nowadays), would you choose to endure a lengthy evacuation to a distant hyperbaric center with a serious delay in treatment, or would you opt for what might be considered risky in-water recompression as a speedier alternative?

Considering how far some Undercurrent readers are prepared to travel on their dive trips, we were surprised in that we had fewer responses to this question than we would normally expect. It's as if it's a taboo subject -- something that people would rather not think about.

However, Larry Bernier wrote from his dive shop, Dive! Dive! Dive! on Con Dao, a remote island off the coast of Vietnam.

"This is a hot subject, and one I have very strong opinions about based on experience. We have a policy of requiring divers to have insurance to cover evacuation costs (currently around $45,000), but our airport is tiny, there are no lights and no night flights, so if you get bent here after 11:00 a.m., you will not be in a chamber in Thailand for [at least] 24 hours. Worst case, if the airport is closed due to strong winds for a day or two, the victim could be looking at days."

"I worried about this a lot, so went ahead and got myself qualified to administer the treatment."

"So far, one staff member with an undeserved inner ear hit and another customer with spreading joint pain have been treated, to 100 percent resolution. We use a Scubapro full-face mask with two ports that delivers both air and pure O2."

"Local divers, with no training, often dive air to 60 meters (200 feet) four times a day, around 20 minutes bottom time, and do the most rudimentary of deco stops, [resulting in] lots of those guys now in diapers, in wheelchairs, or confined to bed for life."

"We have undertaken public education programs for dive safety, and I still have to go out and treat them. Locals have no money for treatment, and we have saved a few lives."

"I am just a dive shop owner, with only two shops on the island, and a low number of customers, so there is no way to pay for a chamber, but we do the absolute best we can."

He told Undercurrent he believes DAN has been deeply engaged in this work, although it is not for public consumption, and he has persuaded a DAN doc to supervise him when he has questions.

"You just have to make the right contacts. A lot of the DAN docs are all for it. For me, heck yes, if the diagnosis is right, I am back in the water in a heartbeat."

Felix Romano Toussieh (Mexico City) approved, writing, "If you are in Cocos and get DCS, what other option do you have, other than in-water recompression? I would pay the $150 every trip I make to have a chamber on board. The question is, would the operator pay for it?"

"I can see the merits of a more informed and formalized approach."

Jim Jenkins (San Francisco, CA) was pleased that Undercurrent had mentioned the subject, and said he would carry a copy of Bret Gilliam's protocol ( with him and give it to cruise directors at the start of each trip he went on.

"I would gladly pay a small premium to be on a boat with its own chamber. $150 is mentioned and would be very reasonable. While the chamber solves one problem (in-water recompression), it creates lots more -- training, liability, etc.  I think there is a growing population of us Baby Boomers who would put 'chamber on board' on our checklists for liveaboards and remote resorts."

Rich Erickson, MS, DDS (Marietta, GA) says a dive boat might need an hour-and-a-half' worth of oxygen at depth to do the in-water recompression, and says "Most emergency DAN DCS kits have only a small bottle of oxygen, so how is this possible?"

Gilliam suggests that liveaboards carry H-cylinders, which can hold roughly 7,000 liters of oxygen. When fully charged, an H-cylinder provides high-flow oxygen to a patient for well over six hours. He says "H-cylinders are standard on most modern vessels, not expensive at all and widely available." Gilliam suggests decanting oxygen to dedicated O2-clean (and in oxygen service) scubasize cylinders for use.

Bob Morris (Wayne, PA) says he would carry Gilliam's procedure as part of his dive gear, wonders about the availability of oxygen in some of the remote places he dives. Keep in mind that in places like Raja Ampat, many liveaboards and dive centers now supply nitrox by de-nitrogenizing air with a membrane system combined with a compressor, but most also have emergency therapeutic oxygen supplies.

Bruce Versteegh (McKinney, TX) has been on liveaboards all over Indonesia, the Solomons, and the Philippines, and has no doubt it would easily be 36 hours to secure treatment.  He thinks establishing an in-water protocol with crew training certification is a prudent option.

"I would accept the risk without reservation. It is too bad that litigation concerns overwhelm common sense. Some variation of a Good Samaritan law needs to be established that holds the dive operator non-liable for emergency treatment protocols when no other viable option exists. . . But, no way are they going to put portable hyperbaric chambers on each ship; they struggle to keep the air conditioning working on most of those boats."

In-water recompression has been going on for years but never formalized. Ken W. Smith (Florida), who has made 3600 dives, writes that he has personally completed several in water deco events while wreck diving in Block Island, RI early 1980s.

"Mild but persistent shoulder pain and moderate to severe skin bends were the two symptoms. Typical dive profiles were 130 ft (40m) for 40 minutes [with air], square. Lots of USN table deco time... almost another 40 minutes I believe."

"In that same time frame, I switched to O2 in my 30 cu. ft. pony bottle for routine deco, once above 20 ft. (6m). Then refilled the pony from a three tank bank of oxygen I brought to the base camp, where we spent nearly a month diving, me as mate on the dive boat Gekos, Capt. Larry Keen, out of Delaware."

"I think I went back to depth, approximately 120 ft. (36m) for just a few minutes, then slow ascent to 20 ft. (6m) and switched to pure O2, as I remember. Stayed until the O2 was depleted, possibly 30 minutes. Pain symptom abated within a few minutes, on that event.  And skin bends subsided on the other event, once on the surface an able to evaluate. I can see the merits of a more informed and formalized approach."

Cindy Boling (Fort Worth, TX) was even more concise: "I absolutely would opt for in-water recompression. Seems it comes down to a very simple decision -- live or die..." Alas, medical decisions are rarely as simple as that.

A final word from Bret Gilliam: "Of course, I would love to see small chambers in remote locations and aboard vessels. But ... that's not going to happen due to cost, liability, and transport of the units. And the size of practical small chambers is so confining that many divers will not fit comfortably in them or even want to subject themselves to the claustrophobic experience."

"Doing the treatment in the ocean is much more comfortable, easy to access, and requires minimal support equipment. I do hope the diving pros on the remotely located resorts and vessels will get the necessary gear and training and be ready when the time comes. It's a very real situation that everyone needs to get their heads around. It's not overly difficult to get ready, and the immediacy of treatment outweighs the very minor risks."

Medical Concerns About In-Water Recompression

John Lippmann, the very distinguished decompression and recompression expert, author of highly rated textbooks on the subject including the seminal Deeper Into Diving, and founder and chairman of DAN Asia-Pacific, wrote the following:

* * *

In-water recompression (IWR) has been used in one form or another for many decades to try to eliminate symptoms of decompression sickness (DCS). Historically, it was predominantly used by diver-fisherman where there was no access to recompression chambers.

Protocols varied, but it often involved descending to depth (often 30-50 m/100-165 ft) breathing air. It was fraught with risk for both the diver and his buddies, and there are many anecdotes of poor and sometimes tragic results.

In an effort to reduce the depth required for IWR, several organizations introduced IWR protocols that used oxygen, rather than air, as the breathing gas. Possibly the best-known procedure was introduced by Dr. Carl Edmonds, of the Australian Navy School of Underwater Medicine. The treatments involve the injured diver re-submerging to a specified depth (usually 6-9 m/20-30 ft) for scheduled times, breathing 100 per cent oxygen. However, oxygen can cause seizures at these pressures; so, to mitigate the risk of drowning in the event of a seizure, the diver should wear a full-face mask.

In the Edmonds' procedure, the diver is also tethered to a shotline marked in one metre increments to control the depth and later the ascent rate (which is one metre per 12 minutes). There needs to be an underwater attendant with the diver and one on the boat. The sea and weather conditions need to be suitable, and the diver needs to be wearing an appropriate wetsuit or drysuit to ensure that he/she doesn't get cold during the several hours underwater, which ranges from about 2 to 3.5 hours. You can read the full protocol here.

With the emergence of technical diving, breathing high oxygen concentrations underwater has become commonplace, as has diving in even more remote locations. The availability of rebreathers enables oxygen-breathing for extended periods. As a result, there are a number of anecdotal reports of divers with symptoms of DCS treating themselves using IWR on oxygen (IWOR). If done in a reasonable fashion, this is often successful. However, the reality is that it is often done in a relatively haphazard manner, increasing the risk of a problem.

Over recent months, DAN AP has received two concerning reports involving IWOR. The first involved a technical diver in Indonesia. He developed mild DCS symptoms after diving and decided to do a shallow dive on his rebreather on a high PO2 to try to resolve them. Although the symptoms receded for a while, they worsened again that evening. After searching the web, he found some IWOR procedure on a chatline and dived again the next day, trying to treat his symptoms. Unfortunately, they became far worse, and he further compounded them by flying home.

The second diver developed symptoms of decompression illness after diving from a liveaboard in the Philippines. He was unconscious for a short time. The dive crew called the DAN AP Diving Emergency Service (DES) hotline and was linked to an experienced diving doctor. The operator indicated that its protocol was to use IWOR, and the doctor advised that the diver should NOT be put in the water due to his unstable condition and that he should remain on the boat and breathe oxygen for several hours while arrangements could be made for further management. The diver improved significantly with the oxygen first aid, but, despite this and against the medical advice, the dive operator insisted that the diver do IWOR.

Had he become unconscious while underwater, he could have died. The dive operator's position would likely be indefensible, given that they had acted contrary to expert medical advice. It is not the role of a dive professional to make what is essentially a medical decision to perform IWOR on a client. Unless they are particularly well-informed, the client would not be in a position to assess the potential risks and balance them against the possible advantages. This is also true of the dive professional.

I believe that IWOR has its place in the management of DCS in remote places. However, it must be done using acceptable protocols, with appropriate equipment, in appropriate conditions and only on a diver who is conscious and stable. Expert diving medical advice should be sought and followed.

Dive operators and divers should not underestimate the effectiveness of properly delivered surface oxygen first aid. If given early, in high enough concentrations and for long enough (often 4-6 hours), oxygen first aid will often reduce or eliminate symptoms of DCS. It is essential that there is an adequate oxygen supply that will last until medical aid is available, or until a diving doctor advises that it can be ceased.

More Next Month.

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