Emergency pressure treatment when bent?

[graywhale]

Case #12. Central Pacific.

Four aquarium fish collectors ascended rapidly from their second 200 feet dive of the day, aborting essentially all decompression. All immediately began experiencing nausea and varying degrees of neurological DCS symptoms. Three of the divers returned to a depth of about 50 feet, but the fourth opted instead to stay in the boat. When the three completed their abridged attempt at IWR (after which all three felt noticeably improved), they headed for shore. Help was summoned, and additional scuba tanks and 100% oxygen were obtained and loaded into the boat. By this time, one of the divers felt only pain in his shoulders, and the other three were experiencing varying degrees of neurological DCS symptoms. The worst of these was diver who did not attempt IWR immediately after the initial onset of symptoms: he was unable to move his arms or legs and was having difficulty breathing. The other three attempted to assist him back in the water, but they eventually gave up, fearing that he might drown (due to his inability to hold the regulator in his mouth). The other three continued IWR, breathing both air and 100% oxygen at 30-40 feet, until nightfall forced them out of the water. That night, all four took turns breathed 100% oxygen on the surface while waiting for the emergency evacuation plane to arrive. The following day, the three who had attempted IWR were flown to Honolulu, where they experienced varying degrees of recovery after treatment in a recompression chamber. The one who did not attempt IWR died before the plane arrived.

 

[graywhale]

"If a consensus was every achieved on an 'approved' method, then it would be great if a training course was available." I agree. And here some excerpts to stimulate that topic:

Methodology of IWR

Once the decision to perform IWR has been made, the next question to consider concerns methodology. The fundamental difference between the Australian Method and the Hawaiian Method of IWR is that the latter incorporates a deeper "air-spike" as an initial step in the treatment. The two methods are analogous in form, respectively, to the U.S. Navy's "Table 6" and "Table 6A" (however, the depths at which 100% oxygen is breathed is shallower, and the durations shorter for the IWR methods than for the chamber schedules).

There are a number of safety advantages to the Australian Method over the Hawaiian Method. Since the only breathing gas of the Australian Method is oxygen, there is no risk of additional loading of nitrogen or other inert gases. Thus, if the treatment must be terminated prematurely (e.g. in response to the onset of nightfall; see Case #12), there is no risk of aggravating the DCS symptoms. Furthermore, the Australian Method may be conducted in shallow, protected areas such as lagoons or boat harbors, where sea surface and current conditions are less likely to be adverse.

We are unable at this time to entirely condemn the Hawaiian Method of IWR, for it may confer important advantages under certain circumstances. Edmonds (1993) suggests that the Australian Method of IWR is "of very little value in the cases where gross decompression staging has been omitted", presumably because such situations may require recompression to depths in excess of 30 feet (9 meters) (although see Case #7 and #8). Under such circumstances (e.g. `interrupted decompression' situations), the "spike" might be advantageous. Nevertheless, we are compelled to strongly discourage technical divers from incorporating an "air-spike" into IWR attempts, at least until additional verification of its efficacy can be established through empirical and theoretical lines of evidence.

In the Absence of Oxygen

Perhaps one of the most critical conditions affecting the decision to perform in-water recompression is the availability of 100% oxygen, especially in a system capable of delivering it to a diver underwater. Although the risk of acute oxygen toxicity symptoms is certainly a cause for concern, the added advantages to effective decompression/recompression are tremendous. However, there will be cases of DCS which occur in situations where 100% oxygen is unavailable. Surely, in light of the theoretical disadvantages of attempting IWR using only air, such a practice would seem absurd. Indeed, all of the cases for which IWR left the divers in worse shape than when they began (e.g. Case #3 and #10), involved air as the only breathing mixture. Furthermore, the diver in case #8 did not improve after air-only IWR, and may have exacerbated his condition during his failed attempts. Nevertheless, the vast majority of the reported "successful" attempts of IWR (including Case #2, #4, #5, #6, and #11 above) were conducted using only air. Several early publications proposed methods of air-only IWR (e.g. Davis, 1962), however none are presently recognized as practical alternatives to oxygen IWR.

In two of the above cases of air-only IWR (#4 and #5), the afflicted divers followed the advice of their decompression computers in determining an air recompression/decompression profile, with apparent success. However, as pointed out by Overlock (1989), use of computers for this purpose "was never intended by the designer/manufacturer, nor would it be recommended". The reason this practice is not advisable is that the algorithms utilized by such devices for determining decompression profiles do not account for the complexities introduced by the presence of intravascular bubbles, which can dramatically affect decompression dynamics (Yount, 1988).

Edmonds et al. (1981, p. 173) sum up air IWR as follows: "In the absence of a recompression chamber, [air IWR] may be the only treatment available to prevent death or severe disability. Despite considerable criticism from authorities distant from the site, this traditional therapy is recognized by most experienced and practical divers to often be of life saving value".

Our suggestion (and an underlying message of this article), is that technical divers, who are already familiar with the use of 100% oxygen underwater as a decompression gas, should add to their equipment inventory the necessary items (such as a full face mask and large supplies of extra oxygen) to perform proper IWR procedures. Having done this, these divers avoid facing the decision to perform the risky gamble of air IWR.

 

[DandyDon]

Thanks for posting cases of IWR gone wrong. Case # 10 is the worst. In case #4 the divers died, but we really do not know why and we do not know what the divers did. Also they went down without a safety diver. There is a lack of details.

I think that the best point offered to that was "Either method (surface O2 or IWR) could work and either may fail. The difference is that one method places the casualty in no further danger, wheras the other places them back into a situation where any number of complications could easily kill them."

That calls for simplicity. and here the safest procedure is the Australian method where by the victim is taken back down to 30 feet on 100% oxygen with a safety diver and slowly brought back up. With this, the IWR can be broken off at any time and the victim brought back to the surface without further compounding the issue. No oxygen toxicity, not additional Nitrogen load, etc..

No OxTox?! Huh? Approaching 2.0 is a severe risk for OxTox. Without a full face mask, even a safety diver would be challenged to save the other diver if he took a hit. You'd also need sufficient O2 supplies and O2 clean reg. You realize how rare these three items are on dive boats?

Eh, 30 ft is not even much for recompression compared to standard treatment tables is it?

Have you considered my portable PVC chamber? :silly:

 

[DCBC]

Divers who insist on decompression diving where a chamber is not easily available, should consider purchasing one. Portable chambers are available (such as the Healing Dives Mini and others) which are available for purchase for less than $5000. How many of us spend 5 grand on camera equipment or more for CCRs? If a diver wants to take the risk of diving deep, s/he should have the foresight to choose a location where a chamber is available or take his own. How's that for a radical approach?

 

[graywhale]

Thanks guys,
If a portable chamber is so cheap, why doesn't every live aboard carry one? They should. I'm going to look into that. If supplying oxygen is too complicated, then recreational divers should learn IWR without oxygen in cases where IWR would clearly be beneficial. But when not using oxygen, it is even more important not to screw up. It takes deeper and a far longer IWR.

How much do Full Face Masks cost and can they be used with O2 tanks or do they have to have a hose from a surface source? What is the range of prices for portable chambers?

An alternative to all this, IWR profiles using nitrox with regular scuba gear should be developed. There are various profiles already developed for various situations and the US navy has 3 that I have seen with one for use without any O2.

The first step in all if this would be to have the medical community agree to prescribe IWR and the doctors need to get trained on exactly how, as each situation will require a slightly different procedure, depending on symptoms, weather, equipment, competence, etc...If the doc determines it would be beneficial and the divers are competent to execute the IWR and follow instructions and have sufficient equipment, he can prescribe one over the phone and give them the instructions. But only if the doctor is familiar with IWR obviously.

A second step would be to create an IWR manual and have DMs and professional divers trained on it. The analogy is Airline pilots who operate such complex machinery that when confronted with an emergency, one of the first things they do is pull out the manual to tell them how to handle it. Just about every emergency is thought through in there and the course of action described.

Perhaps we should have a similar "Bends Manual" carried on commercial operations and with minimum equipment carried to deal with IWR. Of course the first reaction of the DM confronted with a certain case should be to call a medic and put the victim on surface O2. As a second alternative if a medic is not reachable can be to pull out the manual and see what it says for their situation.

 

[graywhale]

A chamber treatment can follow up an IWR, where by IWR is used for the speed it provides in recompression, which seems to take the edge off the final outcome in most cases. When bubbles are expanding in the body, there is nothing like immediate recompression. Even if symptoms persist after the IWR, it is likely it do some good in alleviating the situation and the victim can seek further treatment in a chamber later. Again, this is all about cases were a chamber is not readily available, as in more than 3 hours away. In places like Cozumel, you can be in a chamber within 1 hour or less.

But even in cases where a chamber is close by, where there is explosive decompression from deep dives, it is almost a no brainer to go back down immediately and decompress properly before any symptoms are felt. This has proven successful in many cases. In these cases, after 30-60 minutes, the victim would be showing severe symptoms already.

 

[graywhale]

I just looked at the Healing Dives Mini chamber and it would be useless as it only goes to 10-15 feet...........

 

[laurin]

I feel that promoting IWR would probably do more harm than good. It's a workable solution in such a small subset of already small set of DCS incidents that advertising it as a viable option would just cause it to be used even when not beneficial - false optimism. During incidents it would be better to have a clear understanding of realistic options, as decision-making may be affected by stress.

Even if "proper" schedules with all the required kit and gases were outlined by the medical community, it would probably also promote nickle rocketry and DIY "fixing" by the clueless.

To be able to complete the schedules you'd need to be prepared to spend hours in water, both the victim and an attendee. You'd need either really good preparations for exceptional cold-water exposures for everyone on board, or just accept the IWR is only for tropical water. Weather might not play along, and you'd need loads of O2 for the victim and air for others. It would probably be a better idea to thoroughly research your medevac possibilies and maybe invest in a good insurance that would cover even a costly transport than spend lots of effort and resources on preparing for IWR...

For omitted or inadequate deco, going down is pretty much a no-brainer if it can be done safely - but that's not IWR.

I think the above sounds a bit more negative and pessimistic than I feel about IWR, I just think it receives more attention than it deserves.

//LN

 

[Thalassamania]

I just looked at the Healing Dives Mini chamber and it would be useless as it only goes to 10-15 feet...........

It is not designed as a DCS treatment chamber, it is designed for oxygen "therapy" and is being flogged for "off label" uses such as: ADD (Attention Deficit Disorder), ALS (Amyotrophic Lateral Sclerosis), Alzheimer’s, Anti-Aging, Athletic Conditioning, Asperger’s, Autism, Autism Spectrum Disorder, Brain Injury (Encephalopathy), Burns, Cerebral Palsy, CFS (Chronic Fatigue Syndrome), Coma, Cosmetic Surgery (Post-Surgery Healing), Crohn’s Disease, Dementia, Disease Prevention, Epilepsy, Fetal Alcohol Syndrome, Fibromyalgia, Infection, Injury Healing, Insomnia, Lyme Disease, Memory Loss, Migraines, Multiple Chemical Sensitivity, Multiple Sclerosis, Near Drowning, Neuropathy, Parkinson’s, PDD (Pervasive Developmental Disorder), RLS (Restless Legs Syndrome), RSD (Reflex Sympathetic Dystrophy), Seizure Disorders, Skin Care, Sports Injury Healing, Stem Cell Therapy (Pre & Post Stem Cell Therapy), Stroke, Plastic Surgery (Post-Surgery Healing), Post Surgery Healing, Pre-Surgery, Traumatic Brain Injury, Toxic Brain Injury, Wound Healing,, As well as less common Off-Label Uses like: Addiction, AIDS & HIV, Allergies & Asthma, Arthritis (Osteoarthritis & Rheumatoid), Atherosclerosis, Auto-Immune Disorders, Bell’s Palsy, Cancer (Post Radiation & Chemotherapy), COPD (Chronic Obstructive Pulmonary Disease), Chronic Pain, Depression, Diabetes, Down Syndrome, Frostbite, Gulf War Syndrome, Hearing Loss, Heart Disease, Hepatitis, Huntington's Impotence, Infertility, Interstitial Cycstitis, Kidney Disease, Lupus, Macular Degeneration, Menopause Symptoms, Meningitis, Mitochondrial Disorders, Myasthenia Gravis, Ocular (Eye) Conditions, Orthopedic, Osteoporosis, Pancreatitis, Post Polio Syndrome, Protracted Withdrawal Syndrome (PAWS), Psychiatric Disorders Sarcoidosis, Sleep Apnea Spinal Cord Injury, Tinnitus, Transverse Myelitis, Ulcerative Colitis, Weight Loss.

In other words sheer quackery.

On the other hand:
from:

The University-National Oceanographic Laboratory System

Final Report of The Workshop on Scientific Shipboard Diving Safety

James J. Griffin, Ph.D., Chairman
sponsored by
The National Science Foundation and The National Oceanic and Atmospheric Administration

Findings and Recommendations: Recompression Chambers
​

Findings

• A review of the history of academic research diving does not justify requirement of on-board recompression chambers.
• Chambers may be desirable for diving techniques/equipment that are outside the current practices of the scientific divingcommunity .
• Of the chambers available, a double lock multi-place unit is the superior choice

Recommendations

• Normal at-sea scientific diving from UNOLS vessels does not require provision or use of an on-board recompression chamber.
• Diving beyond the experienced norm, especially in a remote site, should reviewed on a case-by-case basis as part of the dive planning process to determine if chamber is warranted
• The general level of emergency medical preparedness should be enhanced encouraging the training of crew members (and even interested research divers Emergency Medical Technicians) .
• In-water, oxygen decompression or the use of NITROX should be evaluated as techniques capable of providing greater safety margins.

 

[Rhone Man]

I just looked at the Healing Dives Mini chamber and it would be useless as it only goes to 10-15 feet...........

I think its potential use must be to try and stabilise until proper recompression therapy can start.

A few years ago they were selling one in the UK very cheaply, where you just hooked in an Aluminum 80 (or, in their case, an 11 litre) turned the valve and it pressurised to 3 ATA, to stabilise the diver till they got to a chamber.