Emergency pressure treatment when bent?

[DCBC]

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

Why do you say that? A 1.5 ATM P2 may stabilize a DCS patient and increase transport safety. Granted, it would not greatly benefit an AGE victim (although it would help), but IWR would be totally useless for AGE, Type III and arguably for Type II DCS.

 

[DCBC]

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.

Commercial practice requires an on-site chamber if undertaking decompression dives. If you want to promote IWR, you would require a standard outlining specific training and equipment. This standard would have to specify the scope of IWR (quite likely to be limited to Type I DCS). Type II may be considered under very specific limitations (i.e. water temperature, availability of safety divers, etc.)?

Personally I think that this would be a stretch, mainly due to the standards already set by the commercial industry (which are internationally recognized). So you would need to set a different standard-of-care. At what point would the commercial standard be required to be met by recreational "commercial" companies operating in the field of decompression diving?

 

[graywhale]

DCBC,
You are correct, about being at 1.5 ATM under O2 would certainly help. So perhaps live aboards should consider carrying one for the reasons you state and used as such. Good point.

To me, the evidence that IWR is helpful and almost never detrimental - that to me is clear. But the concerns raised by many here and elsewhere indicate that it will not get widespread acceptance or use due to doubts, fears, liability issues, etc... and the many variables that have to be considered.

Assuming the dive profile was to plan, the problem is right at the beginning (where else?) with evaluating the symptoms (if they are even DCS related or not, how severe, etc...) and if they are severe enough and setting on quickly enough to justify IWR or not. Here is where the real problem and difficulty arises. If the divers can not evaluate (or get outside evaluation) about the "victims" condition or symptoms, a decision about IWR or not can not even be made. And even doctors struggle when initially trying to evaluate symptoms, if they are mild or with a slow onset. A definitive evaluation can not easily be made even by doctors in those cases. In severe cases and quickly onsetting symptoms, it is more obvious and quick IWR would be most beneficial. But those attending the diver or the diver himself must be able to evaluate the symptoms to even make any kind of decision.

So before we can talk about doing IWR, we must teach DMs how to recognize DCS and evaluate if IWR would even be beneficial, as in many very mild cases, surface 02 is just fine. Another alternative to make it simpler, would be to teach that if symptoms get worse despite surface 02 and there is suspicion that DCS could be the cause, to just do IWR in all suspected cases as per a predefined procedure. Doctors do that themselves when they are in doubt, they send the "victims" to a chamber treatment just in case. And there are cases where it turns out that the symptoms where not DCS related. But a chamber ride does not do any harm, and neither does IWR done right.

To note on case 10 is that we do not know if the outcome with chamber treatment would not have been similar - or perhaps worse - we do not know enough about the details of what the diver did and previous profile. Even assuming it was all down to IWR, those types of outcomes involving IWR are rare. Even incomplete IWR seems to take some edge off. I'm sure there are cases where DCS victims got worse or passed away even with chamber treatment, but nobody is saying not to go into the chamber despite those cases.

And as a reminder, I am only talking about IWR when a chamber is more than 3 hours away. I am not advocating IWR, I am merely here to get answers for myself personally to questions I had on IWR. I think it is not discussed enough given all the medical research already done, rather than too little, as it is clearly beneficial, so we should not hide this or fear that in the if in the wrong hands it will cause more harm than good. With that logic, just about anything will cause more harm than good.

"Evidence" that it is not discussed enough is seen in this debate and the fact I was looking for IWR info and could not find any until I came here on this board. This also shows how good this board is.......thanks all for the lively and honest discussion and exchange of opinions and info.

 

[Thalassamania]

The Healing Dives Mini chamber is of little or no use for diving, it goes to 1.3 ATA, with is about an 8% reduction in bubble diameter, while the slight increase in ppO2 might be of some help, the advantage over just 100% is, in my mind, doubtful. Sure, it's only $5K, but by the time you add equipment to pressurize it a BIBS system, scrubbers, ventilation, fire suppression, etc., you're well into $20K and then you have to train personnel and keep them current.

Last time I looked at it setting up for a real portable chamber was about a $40K to $50K proposition.

 

[DCBC]

The Healing Dives Mini chamber is of little or no use for diving, it goes to 1.3 ATA, with is about an 8% reduction in bubble diameter, while the slight increase in ppO2 might be of some help, the advantage over just 100% is, in my mind, doubtful. Sure, it's only $5K, but by the time you add equipment to pressurize it a BIBS system, scrubbers, ventilation, fire suppression, etc., you're well into $20K and then you have to train personnel and keep them current.

Last time I looked at it setting up for a real portable chamber was about a $40K to $50K proposition.

The Healing Dives units will deliver a pressure equivalent of 10 and 17 feet of sea water. I don't know about you, but I've decompressed at these depths. I believe that this is a much better solution than doing in-water decompression of a DCS victim and believe that it would stabilize the victims of all Type I and most Type II DCS cases. Safe transport to a decompression facility is the goal.

The Healing Dives unit was given as an example, other portable chambers are available; some costing much more money. My point is that it's just money; divers spend quite a bit on equipment for decompression diving. Chamber costs are continually being reduced. A PDC (or DC for that matter) is within reach of a recreational diving facility that caters to recreational divers. If the travelling diver insisted on a chamber being available and restricted travel to those sites that provided these facilities, it wouldn't take long before they were available everywhere. Since the OP was talking about "decompression alternatives," I felt that a PDC was appropriate to bring into the discussion.

Obviously there's no substitute for a Class A or B chamber complemented with trained hyperbaric physicians and MRI support. And of course even if a Class A chamber was available, there is never any guarantee of successful management; people die.

 

[Thalassamania]

The Healing Dives units will deliver a pressure equivalent of 10 and 17 feet of sea water. I don't know about you, but I've decompressed at these depths. I believe that this is a much better solution than doing in-water decompression of a DCS victim and believe that it would stabilize the victims of all Type I and most Type II DCS cases. Safe transport to a decompression facility is the goal...

There is, as you know, a huge difference between decompression and recompression. I know of no protocol, inwater or chamber based that suggests that recompression of a symptomatic diver to even 17 FSW is of any use what-so-ever, especially a symptomatic diver who, once in the portable chamber, can no longer be tended. Were I bent I'd much prefer 100 percent oxygen and supportive medical therapy to isolation in a chamber only capable of 17 FSW.

If you read the UNOLS publication that I referenced, you'll see the scientific diving community's reasons for rejecting your proposed solution.

 

[DCBC]

There is, as you know, a huge difference between decompression and recompression. I know of no protocol, inwater or chamber based that suggests that recompression of a symptomatic diver to even 17 FSW is of any use what-so-ever, especially a symptomatic diver who, once in the portable chamber, can no longer be tended. Were I bent I'd much prefer 100 percent oxygen and supportive medical therapy to isolation in a chamber only capable of 17 FSW.

If you read the UNOLS publication that I referenced, you'll see the scientific diving community's reasons for rejecting your proposed solution.

Regarding your cited document: "Recommendations: 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." This statement does not preclude the use of chambers. In any regard, this is directed at Academic Research Diving. I believe NOAA restricts Scientific Diving on Air to 130 ft and up to 300 ft for CCR.

From what I can glean from the intent of the OP's question, it surrounds IWR. One of the leading advocates for IWR is Dr. Carl Edmonds, Director of the Australian Diving Medical Centre (previously of the Royal Australian Navy School of Underwater Medicine) who developed a technique that has been referred to as the Edmonds Proceedure, where the diver is taken down to a maximum depth of 9 meters on 100 percent O2 for a limited time (30-90 mins dependent upon the symptoms).

The question at hand is that if no decompression chamber is available (say within a 72 hour period) how do you treat DCS? Is it better to:
1. Give O2 and transport
2. Provide IWR (with or without a FFM) with O2 (what if it's not available?)
3. Provide a chamber capable of 6 meters and transport on a treatment schedule that includes O2; or
4. Tell the guy he's just out of luck and to kiss his *ss goodbye

The answer to this question will no doubt depend upon the symptoms and classification of the suspected DCS. What to do....

Perhaps you are confident enough in your hyperbaric expertise to rule-out option 3 and brand it as "sheer quackery." I wouldn't be so quick to judge. Although I'm a certified hyperbaric operator (Class A), my expertise in this area is limited to following a preset protocol by turning a few dials, or in being the guy in the chamber (at the whim of the people in the driver's seat). I'm NOT a hyperbaric physician! So I don't know

Qualified Hyperbaric Physicians do however disagree an the validity of IWR, but few would disagree on the benefits of a r/decompression chamber regardless of capability. I'm aware of what the treatment schedules say, but believe there has to be a benefit of a 1.5 ATM device, if the alternatives are O2 only or IWR. No doubt time and research will tell...

Good discussion.

 

[Thalassamania]

Regarding your cited document: "Recommendations: 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." This statement does not preclude the use of chambers. In any regard, this is directed at Academic Research Diving. I believe NOAA restricts Scientific Diving on Air to 130 ft and up to 300 ft for CCR.

NOAA is hardly representative of scientific diving in the the US, they are not the founders, innovators or leaders in the field.

BTW: The Scientific Diving Community in the US permits air dives to 190 on a routine basis. NOAA goes with 130 since the majority of their people do not meet the training standards of the AAUS.

From what I can glean from the intent of the OP's question, it surrounds IWR. One of the leading advocates for IWR is Dr. Carl Edmonds, Director of the Australian Diving Medical Centre (previously of the Royal Australian Navy School of Underwater Medicine) who developed a technique that has been referred to as the Edmonds Proceedure, where the diver is taken down to a maximum depth of 9 meters on 100 percent O2 for a limited time (30-90 mins dependent upon the symptoms).

I know Carl well, we have served on several panels together over the years. What Carl is advocating with respect to IWR is a problem that is quite specific to the remote Pacific Islands, places that make even Ellesmere Island or Svalbard seem downright cosmopolitan. In these situations not only does IWR make sense, it is the only possibility. That is radically different from the areas where liveaboards operate and to use Carl's statements concerning IWR to advocate either preparing liveaboards for IWR or equipping them with completely inadequate portable chambers should take a backseat to having them subscribe to basic offshore medical support such as that provided by companies such as Medical Advisory Services.

What Carl suggested (in the Bent Issue of aquaCorps, which I happened to work as an editor on) was:

In-water Oxygen Treatment Procedures

Oxygen should be supplied at maximum depth of 9 msw (30 fsw), from a surface supply system. The ascent is commenced after 30 minutes in mild cases, or 60 minutes in severe cases, if significant improvement has occurred. These times may be extended for another 30 minutes, if there has been no improvement. The ascent is at the rate of 12 minutes per metre (4 minutes/foot). A diver attendant should always be present, and the ascent controlled by the surface tenders. The duration of the tables range from 2 hours 36 minutes or 3 hours 6 minutes depending on the treatment options used.

After surfacing the patient should be given periods of oxygen breathing, interspersed with air breathing, usually on a one hour on, one hour off, basis, with respiratory volume measurements and chest X-ray examination if possible. The treatment can be repeated twice daily, if needed.

The equipment required for this treatment is similar to that used in an surface supplied oxygen decompression system with some important differences. In the case of an in-water treatment, a G size cylinder (220 cubic feet or 7000 litres) of medical oxygen is probably adequate though specific requirements can easily be calculated. This is usually available form local gas supply companies or hospitals, although in some cases industrial oxygen has been used. For a diver at rest, breathing this volume of oxygen at a depth varying between 9 meters (30 feet) and the surface is usually insufficient to produce either neurological (CNS) or respiratory oxygen toxicity (see "In Case Of Convulsion" below). Note that all equipment used with pure oxygen must be rated for oxygen service. Also, whenever oxygen is given, the cylinder should be turned on slowly and the flow commenced, before it is given to patients or divers.

A 2-stage regulator, set at 550 kPa (80 psi) is fitted with a safety valve, and connects with 12 metres (40 feet) of supply hose. This allows for 9 metres depth, 2 metres from the surface of the water to the cylinder, and 1 metre around the diver. A non-return valve is attached between the supply line and the full face mask. The full face mask is critical as it enables the system to be used with a semi-conscious or unwell patient. It reduces the risk of aspiration of sea water, allows the patient to speak to his attendants, and also permits vomiting to occur without obstructing the respiratory gas supply.

The supply line is marked in distances of 1 metre from the surface to the diver, and is tucked under the weight belt, between the diver's legs, or is attached to a harness. The diver must be weighted to prevent drifting upwards in an arc by the current.

Note that Carl is calling for repressurization to 9 meters, essentially just shy of 2 ATA, which is very different than the 1.3 to 1.4 ATA you are advocating, just because 2 ATA is helpful does not mean that somthing greater than 1 ATA but less that 2 ATA is of any use.

The question at hand is that if no decompression chamber is available (say within a 72 hour period) how do you treat DCS? Is it better to:
1. Give O2 and transport
2. Provide IWR (with or without a FFM) with O2 (what if it's not available?)
3. Provide a chamber capable of 6 meters and transport on a treatment schedule that includes O2; or
4. Tell the guy he's just out of luck and to kiss his *ss goodbye

Asked and answered by any number of authorities and panels, the consensus being to reduce DCS risk in the first place by making dive profiles less aggressive, gas mixes more benign and then if you have problems to use Option 1.

The answer to this question will no doubt depend upon the symptoms and classification of the suspected DCS. What to do....

Perhaps you are confident enough in your hyperbaric expertise to rule-out option 3 and brand it as "sheer quackery." I wouldn't be so quick to judge. Although I'm a certified hyperbaric operator (Class A), my expertise in this area is limited to following a preset protocol by turning a few dials, or in being the guy in the chamber (at the whim of the people in the driver's seat). I'm NOT a hyperbaric physician! So I don't know

I don't rule out carrying a fully capable chamber, but a chamber that is only capable of 4 PSI over-pressurization I am comfortable branding as quackery.

Qualified Hyperbaric Physicians do however disagree an the validity of IWR, but few would disagree on the benefits of a r/decompression chamber regardless of capability.

Find me one authority that would think that 4 PSI over ambient is worth squat.

I'm aware of what the treatment schedules say, but believe there has to be a benefit of a 1.5 ATM device, if the alternatives are O2 only or IWR. No doubt time and research will tell...

Good discussion.

I doubt that time and research will tell since even 1.5 ATA (note ATA not ATM, and they are really 1.3 ATA) would not be considered potentially useful enough for anyone to be interested in funding the research, the proposal would never make it through peer review.

 

[DCBC]

Asked and answered by any number of authorities and panels, the consensus being to reduce DCS risk in the first place by making dive profiles less agressive, gas mixes more benign and then if you have problems... use Option 1.

In this we agree (as per my initial posts). As to the rest, as I've said earlier, I don't feel my knowledge is so expansive that I can say what is, or is not of clinical value when it comes to discounting potentially new stabilization methods for DCS treatment. In fact even most hyperbaric physicians would want to study something first before discounting it out-of-hand...

Regardless of whom I have known and dove with (which might surprise you), I do not believe that this lends to my personal credibility or knowledge in the matter under discussion.

I appreciate your comments. I'm sure this will not be the first time that we will not totally agree on a discussion, but I suppose that's the value of a discussion board. No one would learn anything by talking to ourselves.

 

[Thalassamania]

In this we agree (as per my initial posts). As to the rest, as I've said earlier, I don't feel my knowledge is so expansive that I can say what is, or is not of clinical value when it comes to discounting potentially new stabilization methods for DCS treatment. In fact even most hyperbaric physicians would want to study something first before discounting it out-of-hand...

Don't you think that if 1.5 ATA was efficacious Carl (and lots of others, including those flogging those useless 1.4 ATA chambers, would have recognized that fact?) Don't you think Edmonds would prefer to go shallower rather than exposing the diver to the potential dangers of a slightly higher ppO2? You don't assume that a treatment modality is useful until it is proven not to be, rather the methodology is quite the reverse.

Regardless of whom I have known and dove with (which might surprise you), I do not believe that this lends to my personal credibility or knowledge in the matter under discussion.

I never dove with Edmonds, so what makes you say that?

I did pass editorial judgment on his article in aquaCorps, corresponded with him concerning it, sat on panels with him at various professional functions and last time I checked, those sorts of things do tend to lend at least an appearance of professional creditability and knowledge concerning the subject.

I appreciate your comments. I'm sure this will not be the first time that we will not totally agree on a discussion, but I suppose that's the value of a discussion board. No one would learn anything by talking to ourselves.

Amen to that.