In Water Recompression vs Missed Deco

[BigJetDriver]

The thought that IWR is a viable option for most recreational divers is just wrong. That's not to say that it can't be done... it ain't rocket science... but if you intend to include IWR in your "bag of tricks" then you need to make sure you and your team (1) are trained to do it and have practiced the procedures under likely scenarios, (2) are routinely "overdressed" to the extent that you can handle the time in the water without severe hypothermia, (3) have enough excess gas, and (4) have enough trained people to keep a support diver with the recompressing diver at all times.
Rick

Now, to get back to the subject at hand, Uncle Ricky has delineated the requirements of IWR quite well, with the exception of the fact that I would quibble with his use of the term "overdressed" as opposed to "properly dressed". If you and your group fit within this category, then IWR is not only useful, but might darn well be your only option, depending upon your location, which would be the proper reason for preparing such procedures.

Under most recreational diving scenarios, however, the conditions listed above do not exist.

 

[pipedope]

Here is something to think about.

Most rec divers doing normal dives are quite close to commercial chambers with medical personel. In these cases it is best to get on O2 and activate EMS to go to the chamber.

Some people go diving in places where the nearest chamber may be DAYS away. In this situation you better have a way to deal with a case of DCI on the spot or the results will not be good.
IWR is a very useful way to deal with a case of DCI in a place where you can't get to a chamber quickly. If you are diving in remote places then it is a very good idea to read up on the liturature, gear up and train for IWR just in case.

If you read the liturature you wil find that there may be significant benefit to the 'in water' part as much as the recompression part. This suggests that it might be useful to float on the surface breathing O2 and a way to improve your situation without the added risk of being at depth.
Just one more option for the bag of tricks.

 

[John C. Ratliff]

I've got a question for the experts on this board (it looks like we have a lot of staff here reading this). I'm a safety professional, and have made comments on other threads which haven't been taken very seriously, but I need to make them again. There are a lot of "recreational" divers here who are doing technical diving that includes decompression. They are now using computers to calculate it, and are coming quite close to the "knife edge" of the no-decompression limits even when they are not doing decompression diving as they are using 90 cubic feet tanks, or sometimes doubles. My questions are:

If we have charters out there who promote this kind of diving, and are several hours away from a chamber, why do they not have a recompression chamber on-board? Also, after reviewing the discussion here, and the fine article that was linked above on IWR, why do the charters not have knowledge/equipment (FFM and on-board O2--enough for 4 hours for two people) to conduct IWR? Finally, if these are what is required to come through a DCS accident or missed decompression, why do divers and dive training agencies not demand these provisions be made on a charter before deciding to dive them?

I'll say it again, if Walter Starck, a biologist who wrote The Blue Reef, A Report from Beneath the Sea* could equip his research vessel on a very limited budget in the mid-1970s with a recompression chamber, why cannot charter dive boats who get paying customers do the same? Let me quote part of Dr. Starck's discussion on recompression, where he told of the need to recompress his wife after a bad "hit":

After what seemed like an eternity, but was probably no more than four or five minutes, we reached the ship. By that time the pain had become virtually unbearable and both of Jo's legs were paralyzed. It was a very rapid and violent hit. Fortunately I had been keeping the decompression chamber pumped up, so it would be ready to go at a moment's notice. We depressurized the outer lock, and Jo got in, or rather we picked her up and just slid her in, as quickly as possible. She helped as well as she could without the use of her legs, and we immediately closed the door and then opened the pressure valve to the outside chamber. As soon as the pressure equalized, the pain ceased, so we knew we had caught the bubble before it had grown too large. We started treatment on pure oxygen for a depth equivalent of 30 feet, but there was still some residual pain. So we went by the standard oxygen treatment table for 60 feet, which calls for a total of two hours' decompression. In the meantime, I got the compressor going and started topping off our air banks and refilling oxygen bottles, et cetera, to have refills for everything if needed. Then I got in te outer lock of the chamber and repressuirzed and went in with Jo and helped her set up a new oxygen bottle; the one in the chamber was getting low. Next I went out and adjusted the pressure lines and fixed her some tea, brought her a pillow, and got fresh carbon dioxide absorbent for the breathing system. Then I locked myself back in with her. We had painted the inside of the chamber with epoxy paint a year ago, but the inside had been sealed for some time, and the fumes were still strong. They aren't dangerous, fortunately, but unpleasant to smell, so we vented the chamber as best we could by letting air in and out simultaneously, maintaining a constant pressure.

After the two hours were up, we gradually bled the last few pounds of pressure out and opened the door. Jo seemed to be in fine shape, with no more pain...

What turned out to be a relatively minor incident could, of course, htave left some permanent disability if we had not had a decompression chamber right on board. It is interesting to note that sports divers have a high incidence of permanent damage from the bends, whereas military divers, who suffer considerably more attacks, have a much lower incidence of disability. The reason is that military divers almost always have ready access to a decompression chamber, and sports divers do not. If a sports diver is hit, he is usually taken by boat or car, or both, on an hours-long journey to a hospital, where people ask slow questions about insurance and financial situations before they will even admit him. So it can be considerable time before the victim gets into a chamber, by then permanent nerve damage may have been done. The key to success in decompression tre.atment is to get the person under pressure immediately, to squeeze the bubble of nitrogen back to a size where it can no longer block a blood vessel. Decompression in the water, where the problem started, is possible as a last-ditch measure, but it frequently makes a bad situation worse. Another dive adds to the bottom time and unsually cannot last long enough to do any good. Also, the most effective treatment involves breathing pure oxygen. I just can't say too much in favor of having a chamber right on hand. The decompression meters and tables that divers use are helpful, but even when they are properly followed, it is still possible to get the bends. The tables are based only on mathematical abstractions and do not represent what is actually happening within the individual human being...

For those who don't know, Dr. Walter Starck is a biologist who specialized in shark research, and the book documents his work on Enewetak Atoll in the South Pacific. He also invented the Electro-Lung, and is considered one of the diving pioneers. (See http://www.goldendolphin.com/wstarck.htm)

SeaRat

*Starck, Walter, The Blue Reef, A Report from Beneath the Sea, Alfred A. Knopf, New York, 1979, page 208-209.

 

[DA Aquamaster]

I still maintain the IWR is at best a last resort alternative, especially in cold water diving.

However, inflatable decompression chambers have been around for a few years and they are rated to 60 ft. which makes the "in water" O2 treatments or Table 5, 6 and 7 decompression treatments possible on the boat - where the diver is going to be warmer and safer in than in the water and the surface support folks can manage the "ascent".

I also recently noticed this particular model which is also inflatable and highly portable. It is rated to 165 ft. and allows for O2 administration with the exhaust vented overboard (which keeps the atmosphere in the chamber at 21% - a nice safety feature.) With the 165 ft rating and O2 capability, it could handle the deeper 165 ft table 3 and 4 treatments as well as the 60 ft tables.

http://www.sub-find.com/chambers.htm

I am not sure what it costs, but it looks and sounds a lot like GSE's Hyperbaric Back Pack which has the same capability and goes for about $15,000. A fair piece of change, but it would be nice to have aboard on a remote wreck diving trip.

 

[Scuba]

If we have charters out there who promote this kind of diving, and are several hours away from a chamber, why do they not have a recompression chamber on-board? Also, after reviewing the discussion here, and the fine article that was linked above on IWR, why do the charters not have knowledge/equipment (FFM and on-board O2--enough for 4 hours for two people) to conduct IWR? Finally, if these are what is required to come through a DCS accident or missed decompression,

Good points.

I speak as a diver non pro. Supply and demand. No demand, no need for the extra cost which impacts bottom line profits if satisfied with boat fills. Most ops follow standard practices which today means minimal oxygen on board and evacuation to chamber within a few hours is acceptable. Most of us either think we can manage the risks to an acceptable level resulting in a very, very small probability of DCS, or are ignorant of the real risks due to a lack of education, and misleading education. Reading posts here reveals there are a many divers who are more accepting of certain risks than the general population, in addition to the implications from participating in diving. Also, many minimize the significance of DCS, probably partly due to the small incidence rate, many succesful full recoveries, and perhaps for some a need for self delusion of the real life changing risks undertaken. One need only notice threads reporting an incident of DCS, where many quickly advice and wish a speedy return to diving, as though it were nothing more than a rite of passage.

It would be interesting to see the results from a dive op employing one of these newer more affordable deco chambers in their boat, in terms of attracting a clientele willing to pay for the benefit enough to make it commercially profitable. I believe this may be commercially viable for some of the live aboards if properly marketed. As you note going to a land deco chamber often takes more than an hour, even when close by. The increasing safety consciouness of many divers, along with the increasing body of research pointing towards the need to treat minor symptoms, and the imperative of prompt treatment, makes a deco chamber and adequate oxygen treatment quite enticing to an increasing number of divers if the cost is right.

I wonder if anyone has any stats on the average time it takes from the onset of symptoms to enter a deco chamber in different dive destinations.

 

[DA Aquamaster]

I wonder if anyone has any stats on the average time it takes from the onset of symptoms to enter a deco chamber in different dive destinations.

It's a good question even for a diver within 30-60 minutes of a chamber. If you call for an evacuation or get there yourself, everything goes well and you arrive at the ER in 60 minutes, how long are you going to wait there while the ER doc decides you need a chamber ride and then how long does it take to get the chamber up and running?

Locally, we are close to a chamber (a single person tube capable of 60 ft only - the closest chamber with full capability is another 500 miles away.) but are a long way from salt water and the ER basically does not encounter diving accident victims moe than once or twice a decade. My spouse was in the ER after a diving accident and since there was no arterial bleeding or bones sticking out, they were treating her pretty much like someone with a bad cold and bumped her to the back of the line. She could have been there for hours before she actually saw some one, let alone the hyperbaric doc. To make it worse, they pitched a fit about her continuing to use our O2 once we were in the hospital - but would not offer their own without her seeing the ER doc first. At that point I became an incredible jerk on the successful assumption that the sqeaky wheel threatening to call the hopsital administrator and an attorney would get the the next available exam room in the ER. Fortuntately, the ER doc was the hyberbaric doc, so we did not have to wait while they tracked him down.

If I could afford one, I'd have my own portable chamber on board my boat - but the cheapest portable chamber I have found is $15,000 which included a week long training program in chamber operation.

 

[Archangel]

tell me if it's a crazy idea or what?

I too was wondering the same thing. While sitting around the dive shop, I asked two SSI master instructors if that was possible, I posed a quick hypothetical that my dive buddy and I were 100 or so feet, he decides to penetrate a wreck, I object but he does it anyway and gets caught or sompthin' like that and I rocket ascent to the surface and get help and re-descend.

The combined answer that I got from both was, when I objected, the buddy should respect my wishes and not penetrate the wreck. . .

. . . the buddy is a fool and I am safety bound to make a slow no deco with a 15 ft safety stop, and then surface and let more experienced divers take over to search the wreck.

While I agree with and didnt question the response, it wasnt really satisfying.

This prolly just muddys the water.

Happy diving,

Tevis

 

[John C. Ratliff]

I too was wondering the same thing. While sitting around the dive shop, I asked two SSI master instructors if that was possible, I posed a quick hypothetical that my dive buddy and I were 100 or so feet, he decides to penetrate a wreck, I object but he does it anyway and gets caught or sompthin' like that and I rocket ascent to the surface and get help and re-descend.

The combined answer that I got from both was, when I objected, the buddy should respect my wishes and not penetrate the wreck. . .

. . . the buddy is a fool and I am safety bound to make a slow no deco with a 15 ft safety stop, and then surface and let more experienced divers take over to search the wreck.

While I agree with and didnt question the response, it wasnt really satisfying.

This prolly just muddys the water.

Happy diving,

Tevis

This brings up another of my pet pieves, and that is the lack after all these years of an adequate communications system. We had the same problem with loggers in the 1970s, who would get injured, and bleed to death because they could not communicate with anyone. And this is after we had landed men on the moon, and talked to them directly! We are still there today. If there were communication between the divers and between the divers and the boat, this would not happen. It doesn't happen today with loggers, as they became convinced of the use of FM radios rather than "Talkie-Tooters" which were basically whistle signals (and the cutters did not have even these). So what about communications systems for divers; we've got the "Buddy Phone" available, but no body talks about it. This is just one of the communications systems available, but you may want to take a look:

http://www.oceantechnologysystems.com/

SeaRat

 

[ocvantol]

Here's a nice document that I picked up from the web a little while ago.

 

[DA Aquamaster]

This brings up another of my pet pieves, and that is the lack after all these years of an adequate communications system. We had the same problem with loggers in the 1970s, who would get injured, and bleed to death because they could not communicate with anyone. And this is after we had landed men on the moon, and talked to them directly! We are still there today.

I agree it's frustrating, but the place we are still at today is cost. Pony bottles and octopus second stages, for example, were also available in the 1970's but were not common as the additional cost was a fairly substantial investment over the basic scuba equipment.

It's the same today. If you asked recreational divers to spend another $500 to $1000 on a com system, many would not be willing or able to purchase one. On the other hand, if the price were $200, it would be within range of many many more divers. That would just leave you with a need for industry standards on frequencies and bandwidths so that a diver with brand x could talk to a diver with brand y.

And that brings up a whole new problem which would be 20 divers off a cattle boat all talking over each other, generally ruining everyone's peace and quiet and most likely preventing the clear transmission of an emergency message anyway. That would require selectable frequencies so that buddy teams of maybe 3-4 divers each could operate on a discreet frequency. That feature then further increases cost and complexity.

I have no doubt it will happen but it will take the same technological advance that took electronic calculators from being very expensive and rare items to being very inexpensive everybody has them items over the course of about 20 years.