Australian Method IWR Equipment

[DocVikingo]

Thanks for taking the time to research a bit of what is already in our archives. Not having to continually re-invent the wheel saves time & bandwidth.

As you appreciate, IWR should only be considered as a last resort (although my article paints some desperation scenarios that are quite possible), and then only when there are the conditions, gear & personnel to support it, and the diver is medically, physically & mentally able to tolerate it.

Under those circumstances, some knowledgeable folks view it not as a "good way to kill yourself," but rather as a fighting chance to avoid very serious neurological impairment. The Australian method is among the more conservative of the techniques. If I were facing the possibility of permanent paralysis, permanent loss of bladder control or the like, then if the ducks were in a row I'd very likely give it a shot.

I would also fully respect the decision of a stricken diver to stay topside and receive whatever conservative treatment was available until emergency services arrived.

In my research/interviews for the Undercurrent piece you referenced, I found more successes than horror stories even when the conditions for IWR were less than ideal, e.g., no or not enough 100% 02.

As regards your questions, obviously much of this has not been studied. The following responses are based on my knowledge of how IWR is approached by its proponents. Keep in mind that as one departs from the optimum circumstances for conducting each type of IWR the risks of these already controversial techniques almost certainly very rapidly increase.

1) (Q) I assume no form of IWR is possible without pure O2? Could the procedure be carried out using standard air if that was all that was available?

(A) It is best to use highest concentration 02 appropriate for the depths suggested by the particular technique. For the Australian method, 100% is directed.

Some have suggested that if pure 02 was not available, the highest concentration of EAN on board would be next in line. If nada, then air.

2) (Q) Could this method be used as a preventative measure for someone at increased risk of DCS, but who was sign/symptom free? If someone were to, say, miss a required deco stop, could they immediately switch to O2, select a tender diver, and re-descend to 30 feet to start the procedure in an attempt to prevent the onset of DCS?

(A) Not recommended. There are other approaches for situations like missed deco obligations. The suggestions below by Dr. Deco are an example, and there are recognized protocols.

3) (Q) 1ft/4min is an EXTREMELY slow ascent rate! 30ft * 4min/ft = 120 minutes to surface. That's 2 hours! In cold water where an additional 2 1/2 to 3 1/2 hours under water may not be possible, what happens if a 1ft/min or 1ft/2min ascent is used? Would that substantially negate any benefits gained from the 30-90 min at 30 feet?

(A) This is at present unknown. If I were overseeing this method of IWR and a 1ft/min or 1ft/2min ascent was dictated by unexpected gas limitations or diver inability tolerate a slower ascent, then I believe that I'd give the slowest ascent rate possible under the circumstances a go, within sensible limits, of course.

4) (Q) What minimum equipment would be necessary to make this option possible? At the very least, I assume some method of anchoring at 30 ft and ascending slowly, sufficient available O2, a knowledgeable tender diver, and environmental protection adequate for the additional period of immersion would be required.

(A) This would seem to be a minimum. Technically, a full face mask with demand valve & surface supply system, or helmet with free flow, a reliable form of communication system between patient, attendant & surface, preferably voice communications, are required. A good book for both tender & victim might be nice as well.

5. (Q) For a rough calculation of what constitutes sufficient O2, how does this look? Assume a SAC of 1cf/min? 30 feet = 2 cf/min O2 consumption. 30 min = 60cf, 60 min = 120cf, 90 min = 180cf. Ascent is 120 min at an average consumtion rate of 1.5cf/min = 180cf. For the maximum treatment of 90 min + ascent, 360cf minimum would be necessary? For the minimum treatment of 30min + ascent, 240cf would be needed? That could be done with a set of double 120's of pure O2.

(A) Haven't worked it out, but, yes, I'd say in a calm diver under conditions of minimal exertion you could do it on double 120s of pure O2.

Please understand that I am neither encouraging nor discouraging the use of IWR. There are lots of "ifs," "it depends" & uncertainties.

Happy holidays.

DocVikingo

 

[pescador775]

DJHALL, the above is good advice. I can only give an opinion based on my experience with bends, It's no fun. I omitted a few minutes of deco and ended up using a cane for six months. I had dived for many years with some technical infractions along the way, and with no consequence of note. However, on the 'dcs day', I was dehydrated, chilled and tired, also older. This is when stuff happens.

For a young person is good shape who has shaved more than a couple minutes, I would advise using Dr Decos technique or surface breathing of O2. For older, overweight individuals, or with large infractions, it's time to get ready for a dive, your call. If symptoms appear, especially weakness, pain in the stomach and back or partial paralysis, a 30 min dive to 30 feet on O2 is probably the only way to save yourself unless a chamber is immediately available. A chamber which is hours away is an hour too far.

You will need assistance. I could have made the recompression dive myself with help getting into the water and preferably a 'tender'--- if only I had O2 available in that remote place.

Today, when Scuba diving is planned from my boat, I carry two 40 cf O2 tanks manifolded together with a diver's O2 regulator and medical regulator/mask. I'll do what I have to do.

Often, there's no way to do the slow walk up unless you like recompressing at night or freezing to the bone. Ascend slowly and watch your gas supply.

 

[djhall]

If symptoms appear, especially weakness, pain in the stomach and back or partial paralysis, a 30 min dive to 30 feet on O2 is probably the only way to save yourself unless a chamber is immediately available. A chamber which is hours away is an hour too far.

This may be. I am still a complete novice on diving medicine, and medicine in general for that matter. However, the following propositions seem logical enough at first glance. If the problem with DCS is the PRESENCE of gas bubbles in the tissues, then the effects should go away when the bubbles dissipate either naturally or with the assistance of a recompression chamber. In that case, a recompression chamber would simply speed the process of recovery. If the problem with DCS is the FORMATION/GROWTH of gas bubbles in the tissues, then the key to minimizing the effects of DCS would be preventing the formation/growth of bubbles in the first place. If that is true, then damage is already being done at the onset of symptoms, and, like you, I don't see how a recompression chamber as little as an hour away is going to save you.

Of course, if the issue was truly this simple, then doctors and diving medicine experts would have nice, simple, precise answers for us regular joes. I suspect the bubbles grow over time and damage from the bubbles gets greater the longer they are present, so a recompression chamber could halt the growth of the bubbles and stop addiditonal damage from occuring. In that case, how could anyone know if the bubbles will grow slow enough to allow time to reach a recompression chamber or not?

I can imagine being on a boat, being bent, feeling the symptoms spreading and growing, and knowing that it will take time for the ambulance or helicopter to arrive, time to transport to the chamber, time to get checked by the doctors, and so forth. The feeling of helplessness, the fear, the urge to do something to fix it NOW, combined with the simple logic of the guy who says, "Well, gee, you got bent by coming out of pressure too fast, you get fixed at the chamber by being put under pressure again, and we've got a couple extra tanks and plenty of water pressure right here," could all add up to making a hasty decision about something that could be either really tragic or your best shot at escaping permanent damage depending on who you listen to/believe. I figure I will just have to learn everything I can about both sides of the issue to be confident I'll make make the best decision I can if the need, god forbid, ever arises.

 

[Hamster]

The Australian Navy has I believe a protocol for emergency IWR. It is something to be used in an emergency. I cannot remember the details but it is not something to be attempted by recreational divers due to:
 Insufficient gas supply, remember both the victim and buddy will need to be supplied for possibly several hours;
 Inadequate thermal protection for a long period in the water; and
 Placing a panicky back into the water is asking for trouble.

Any attempt at IWR by those lacking the equipment and training is likely to make a bad situation far worse.

The first-aid treatment for suspected DCS as taught to recreational divers in Australia is O2 on the surface and the most rapid transport possible to the nearest chamber.

 

[pescador775]

So, DJhall, you're going to learn everything about it that you can? That's sensible. Lord knows, there are any number of nervous nellies and hypochondriacs. Everybody with a sprained shoulder, rash or earache phones in here to relate their chamber experience wondering why they don't feel better. Often, those with overt illness, the flu or suchlike, think that it's pressure related because they happen to a certified diver. It's just human nature. The apparent bona fide cases, such as subcutaneous emphysema, are lost in the din. I can only surmise the number of divers who request on board O2 treatment; but I've heard that boat captains are very conservative about dispensing their oxygen supply for obvious reasons.

When and if you get your first hit you may bless the captain who had the responsibility and forethought to carry an oxygen tank. Personally, I would not make an IWR dive if I had a suspected sprain or other vague twinge of pain. Surface O2 might be prudent if the pain worsens and one certainly shouldn't fly until a diagnosis. However, when your legs suddenly give out and you feel that someone hit you in the back with a hammer the time for dithering is over. You have no more than 20 minutes before permanent disability sets in. In my opinion, an oxygen dive is your best chance if you are able. If you (collective 'you') are incapable, then surface administered O2 is the only option. I'm not referring to a mickey mouse "D" bottle but a 70 cu ft tank or similar. If the rebreather mask (with bag) has an aperture it should be blocked with tape. The flow should be set to 15 ltm at least, or use a demand regulator. Only pure oxygen will be of any real help. This is all my opinion only but I have done some of the research that you've to undertake, and I find that many divers have been saved by IWR. I personally know of cases among friends in Hawaii. I also have friends who did not have this option and are in a wheelchair, permanently. I have previously mentioned names on this board.

Now, IWR with air is a different matter. It has been done successfully but is more complicated and carries more risk, IMO. I do believe that anyone who anticipates this undertake extensive due diligence. Even so, it should be a last resort.

 

[djhall]

pescador775,

From what you have seen, could something worthwhile be done using a single 120/130cf tank of pure oxygen? I could theoretically see carrying around your own large oxygen tank with surface and sub-surface masks for use as the situation dictates. But doubles??? of pure Oxygen??? lugged around solely as a precaution???? a single, maybe, but O2 doubles sounds fairly difficult and expensive to be carried by a single diver.