Alternative to Chamber?

[tgsmith]

I thought the issue was only with saturation divers that spend hours and hours in a helium enriched environment during decompression?

Is that not the case?

That's what my idea was too.

DCBC, in regards to your response to my post, what sort of safe guards are commercial divers taking that you believe we should also be taking?

Also if you could clarify about the exposures of recreational divers and their risk for bone necrosis. As Sloth pointed out and I originally prefaced, I didn't think osteonecrosis was a concern. Is a 20 minute BT at 300 feet(which happens relatively infrequently for most of us) really enough of an exposure to cause concern with osteonecrosis?

Feel free to PM me as it isn't directly relevant to the thread.
Looking forward to your response.

Thanks,
Tyler

 

[Gene_Hobbs]

I thought the issue was only with saturation divers that spend hours and hours in a helium enriched environment during decompression?

Is that not the case?

Interesting turn... Here is another one worth a read.

Cimsit, M; Ilgezdi, S; Cimsit, C; Uzun, G (December 2007). "Dysbaric osteonecrosis in experienced dive masters and instructors". Aviation, Space, and Environmental Medicine 78 (12): 1150–4. doi:10.3357/ASEM.2109.2007. PMID 18064920

Lamar also wrote a good article on TDS a while back.

It is never bad to review the long term health effects of diving...

 

[Thalassamania]

That one is worth reproducing the abstract:

Cimsit M, Ilgezdi S, Cimsit C, Uzun G. Dysbaric osteonecrosis in experienced dive masters and instructors. Aviat Space Environ Med 2007; 78:1150-4. Introduction: Dysbaric osteonecrosis (DON) is a type of aseptic bone necrosis of long bones such as the humerus, femur, and tibia. It is observed in workers who perform in high-pressure environments. Methods: There were 58 volunteer divers included in this study who had performed at least 500 dives, were working as a dive master or instructor, had never performed industrial and commercial dives, and did not have a diagnosis of osteonecrosis. Radiological evaluation was performed according to the guidelines suggested by The British Research Council Decompression Sickness Panel. A total of eight X-rays were taken per patient. When suspicious lesions were detected, MRI of the region was performed. Results: Of the 58 divers, 2 were eliminated because of inadequate X-ray studies. A total of 18 DON lesions were detected in 14 of 56 (25%) divers. Age was the only variable independently associated with the development of DON (P < 0.05). Discussion: The DON prevalence of 25% in this study is high considering the dive instructors had thorough diving training and strictly practiced the decompression rules. We believe this high prevalence is a result of frequent and sometimes deep dives for many years. Our findings raise the question of whether these divers can be seen as &#8220;sports divers&#8221; or should be seen as &#8220;occupational divers.&#8221; If the latter description is approved, dive masters and instructors should be kept under periodic screening for DON lesions just like professional commercial divers to help reduce the morbidity associated with this disease.

 

[Sloth]

That one is worth reproducing the abstract:

Cimsit M, Ilgezdi S, Cimsit C, Uzun G. Dysbaric osteonecrosis in experienced dive masters and instructors. Aviat Space Environ Med 2007; 78:1150-4. Introduction: Dysbaric osteonecrosis (DON) is a type of aseptic bone necrosis of long bones such as the humerus, femur, and tibia. It is observed in workers who perform in high-pressure environments. Methods: There were 58 volunteer divers included in this study who had performed at least 500 dives, were working as a dive master or instructor, had never performed industrial and commercial dives, and did not have a diagnosis of osteonecrosis. Radiological evaluation was performed according to the guidelines suggested by The British Research Council Decompression Sickness Panel. A total of eight X-rays were taken per patient. When suspicious lesions were detected, MRI of the region was performed. Results: Of the 58 divers, 2 were eliminated because of inadequate X-ray studies. A total of 18 DON lesions were detected in 14 of 56 (25%) divers. Age was the only variable independently associated with the development of DON (P < 0.05). Discussion: The DON prevalence of 25% in this study is high considering the dive instructors had thorough diving training and strictly practiced the decompression rules. We believe this high prevalence is a result of frequent and sometimes deep dives for many years. Our findings raise the question of whether these divers can be seen as “sports divers” or should be seen as “occupational divers.” If the latter description is approved, dive masters and instructors should be kept under periodic screening for DON lesions just like professional commercial divers to help reduce the morbidity associated with this disease.

Interesting, thanks Gene for the reference.

Thal, you ever thought of being screened?

 

[DevonDiver]

Thanks for that Thal.... it never occured to me.

 

[DCBC]

DCBC,
I stand corrected, you are right, there is no real difference between the gases. And I hear you on the water conditions. You are professional and don't go without having a contingency plan. I am advocating the same for recreational divers. We've gotten to the point where someone reported a group dive with one participant wearing street pants and a yellow rain coat.

In reality, DCS can kill or permanently harm an individual diving even shallow. In areas where medics and chambers are not too far away, perhaps the divers can rely on that fact. But when that is not the case, divers and DMs should have a contingency plan, even if they are not tech divers and in my untrained and inexperienced opinion, it seems logical to include IWR in a contingency plan, even if it is just a tank of oxygen at the harbor in an area of 30 feet. In the workshops they disclosed that they have lowered a chair to sit on off a pier. So it doesn't have to be complicated if it is planned out in advance if you're very far from any chamber and something real bad happens.

Hoping that nothing too bad happens far from facilities is not a contingency plan in my book, that's why I'm all for IWR in the proper situation. In any case, if the victim is not too bad off on symptoms yet, no harm will likely come of IWR and further treatment can happen later or concurrent with arranging for transport.

I agree, good discussion and I mean on disrespect to anyone, just provoking thoughts and an exchange of info, which I think has happened.

I cannot help but wonder how many recreational divers really have a workable contingency plan on every dive? For that matter, how many Dive Operators do? I know what most of the certification agencies say about this and what I teach my students to do, but does every dive boat in the world have O2 available? Probably not....

There's nothing the matter with you or anyone else doing IWR, unless I'm the victim or the victim is someone I care about. Should you be unsuccessful, I would thank you for trying, but you could expect a lawsuit. If you transported with O2, I believe that the diving industry at large would say that you did the right thing.

Thanks for the open-minded conversation.

 

[DCBC]

I thought the issue was only with saturation divers that spend hours and hours in a helium enriched environment during decompression?

Is that not the case?

No Sloth, as others have mentioned the problem is not limited to saturation dives.

 

[DCBC]

DCBC, in regards to your response to my post, what sort of safe guards are commercial divers taking that you believe we should also be taking?

Also if you could clarify about the exposures of recreational divers and their risk for bone necrosis. As Sloth pointed out and I originally prefaced, I didn't think osteonecrosis was a concern. Is a 20 minute BT at 300 feet(which happens relatively infrequently for most of us) really enough of an exposure to cause concern with osteonecrosis?

Feel free to PM me as it isn't directly relevant to the thread.
Looking forward to your response.

Thanks,
Tyler

Hi Tyler,

Where do I start? Perhaps by establishing my limited knowledge of this area, in-that I'm not a Hyperbaric Researcher or Physician. If I was, I don't think I could honestly tell you much more other than it's believed that age, physical condition and the number of previous exposures (which are believed to be accumulative) are contributing factors.

As a research diver at the Experimental Diving Unit at the Defence and Civil Institute of Environmental Medicine, I assisted medical experts develop the DCIEM Air tables (in the 70's) and the Helium-Oxygen tables in the late 80's (you don't have to be too bright to be a guinea pig). These ended up replacing the U.S. Navy tables for operational mixed gas diving to 100 M.

I wouldn't be surprised if my diving experiences put me in a wheelchair in the next 10 years. I know commercial and sport divers who have died and others who have been crippled over the years. I'll keep my fingers crossed.

To highlight that there is no right answer to the problem, I'd point to the high number of variances within breathable gas decompression tables. Commercially, each company makes a choice which one they will follow and this is susceptible to change. Even hyperbaric treatment of DCS is not standardized (as noted in my previous post involving the Israeli Hyperbaric Unit).

Regarding the type of safe guards utilized by commercial divers that you should consider; I would only suggest:

1. That you plan your dives well within the limits (I've known many that have pushed the tables). Be realistic about your condition and fat content. I, like many of my recreational counterparts have not retained the body of a Greek god. If you are a SEAL, many of the tables have been designed for you. If not, back off a bit.

2. Have a realistic assessment of the dive plan. Things go wrong and time is absorbtion. Give yourself a cushion.

3. Suggested decompression times are minimum times. More is generally better.

4. Most divers ascend much too quickly. Slow down.

5. Always dive with O2 immediately available and be prepared to treat for shock. Have all the emergency numbers you need and a reliable method of communication.

6. All diving has an element of risk. Breathing mixed gas under pressure increases it. Use good judgement where, when and how you dive. Because you can do a thing doesn't mean you should. Peer pressure is for fools; you make the decision.

You most likely do all these things anyway. As you might have already gathered, I'm not a fan of IWR, but that is a choice you will have to make.

Commercial divers take carefully calculated risks, but if you dove with a good one, you'd think that he always over-plans and iss an old lady when it comes to safety. Diving at 2 to 300 Meters saturated will do that to a guy.

Hope this wasn't too long winded and is of some help. Take care.

There are old divers and bold divers, but no old bold divers.

 

[graywhale]

DCBC:

"Should you be unsuccessful, I would thank you for trying, but you could expect a lawsuit. If you transported with O2, I believe that the diving industry at large would say that you did the right thing."

That's exactly right. And that's what stops IWR even when it is a no brainer, see below:

ED KAY: ....I&#8217;m aware of one case in Seattle where a diver was lost because of a malfunction in an
auto-inflator. If that diver had been taken down immediately and treated on a surface
decompression table before the symptoms of decompression started, I think he&#8217;d be
alive today.

I don't think there should be much argument to Dr. Kay's assessment for that case, at least not for me, but I'll leave everyone to make their own. In that situation, many operators DMs would think of the liability issues and lawyers, etc...if complications set in or IWR didn't work well, etc...that's a shame. So the legally safest course is taken, even when it's not the best for the diver- at least that's my hunch and I admit I could be wrong there.

DCBD, I don't think it takes painstaking contingency planning to decide on IWR or not for accidents, but a general training, awareness and certainly equipment availability. Like a general first aid treatment plan, were afterward the victim is taken to the medic and.or chamber on surface oxygen. For myself, I've already formulated a contingency plan for hypothetical accidents in cases were:

1. There is no oxygen
2. There is oxygen
3. There is Nitrox
4. And how much of the above is still available (all tanks sucked dry?).
5. How far a chamber is

It's a general IWR plan, especially when stops are blown or explosive recompression happens - for what ever reason. Usually these things are obvious and you know there is a problem right away even without the onset of symptoms, like with the diver in Seattle.

However, more difficult is when everything was followed to plan and symptoms set in anyway. For the decision to do IWR or not, it would depend on the severity and the speed of symptom onset. That is if the symptoms are mild and appear after more than 1 hour, IWR is not called for. Surface 02 treatment or chamber delay is fine. If someone feels symptoms a few minutes after surfacing and getting worse by the minute, recompression is very urgent. The option of IWR should not be thrown out in such a case as even minor delays in recompression can be deadly or crippling in situations like these. If the victim is already unconscious, that is really not good and would preclude IWR.

But these are my thoughts and my conclusions gleaned after reading many cases and physician opinions. IWR is mostly not recommended by physicians, because they don't trust the other divers to be able to do it properly. There are many possible complications, but when it is clear that immediate recompression would help, even in severe cases, the case history shows people have been saved by IWR. I have yet to read a single case where someone died or was hurt due to or while doing IWR. Not a single one.

If anyone knows of one, please post it. It would be very helpful.

 

[DCBC]

DCBC:

DCBD, I don't think it takes painstaking contingency planning to decide on IWR or not for accidents, but a general training, awareness and certainly equipment availability. Like a general first aid treatment plan, were afterward the victim is taken to the medic and.or chamber on surface oxygen. For myself, I've already formulated a contingency plan for hypothetical accidents in cases were:

1. There is no oxygen
2. There is oxygen
3. There is Nitrox
4. And how much of the above is still available (all tanks sucked dry?).
5. How far a chamber is

The fact that you have a plan is to your credit. However I cannot help but repeat that the Dive Supervisor / Divemaster has a duty to take reasonable safety precautions. O2 should always be available at a minimum. It's also useful to keep in-mind that most successful IWR has been accomplished utilizing a FFM and in-water O2. Should IWR be in your plan, you will need this equipment (your plan may be used as evidence against you, so at the very least it should be technically accurate).

The IWR cases I've read are largely Type I and light Type II. There is of course the problem with trying to treat complex Type II or Type III in this way. Diagnosis may also be a problem. How many Divemasters / Instructors could accurately diagnose the victim properly by degree of severity? Will more harm be done than good? Don't forget the liability factor and the cold water. I wish you luck!