Definitive diagnosis of decompression sickness

[tedb]

Definitive diagnosis of decompression sickness.

I am interested to know if there is a definitive and objective test for diagnosing DCS.

Everything I can find about the subject implies that diagnosis always relies on a subjective assessment of the signs and symptoms by a qualified individual. Is there any clinical test which can establish the presence or absence of gas bubbles in the tissues?

My concern is that a physician, being aware of the dire consequences DCS will tend to make false positive diagnoses from symptoms which suggest DCS but in fact have a different cause.

Following a diagnosis of DCS the victim is required to undergo uncomfortable, expensive and time-consuming treatment and restrictions (for instance no-flying) are placed on his or her life for a lengthy period. The incident is also reported and used as scientific material on which future advice to divers will be based.
For both these reasons it would be helpful if suspected cases of DCS could be objectively confirmed.

 

[captndale]

Definitive diagnosis of decompression sickness.

I am interested to know if there is a definitive and objective test for diagnosing DCS.

Everything I can find about the subject implies that diagnosis always relies on a subjective assessment of the signs and symptoms by a qualified individual. Is there any clinical test which can establish the presence or absence of gas bubbles in the tissues?

My concern is that a physician, being aware of the dire consequences DCS will tend to make false positive diagnoses from symptoms which suggest DCS but in fact have a different cause.

Following a diagnosis of DCS the victim is required to undergo uncomfortable, expensive and time-consuming treatment and restrictions (for instance no-flying) are placed on his or her life for a lengthy period. The incident is also reported and used as scientific material on which future advice to divers will be based.
For both these reasons it would be helpful if suspected cases of DCS could be objectively confirmed.

To start out, I'm not a doctor (although I might play one on the internet).

Doppler sonar can be used to detect bubbles in circulation. The presence of bubbles does not necessarily indicate decompression sickness, but large numbers of larger bubbles do have some positive correlation.

Since the signs and symptoms of decompression sickness are often ambiguous and may also be caused by things completely unrelated to diving, diagnosis is difficult. It is my understanding that the only way to definitively diagnose decompression sickness is to recompress the patient. If the symptoms go away, or are relieved by recompression, then the diagnosis is decompression sickness.

 

[BigJetDriver]

Definitive diagnosis of decompression sickness.

I am interested to know if there is a definitive and objective test for diagnosing DCS.

Everything I can find about the subject implies that diagnosis always relies on a subjective assessment of the signs and symptoms by a qualified individual. Is there any clinical test which can establish the presence or absence of gas bubbles in the tissues?

My concern is that a physician, being aware of the dire consequences DCS will tend to make false positive diagnoses from symptoms which suggest DCS but in fact have a different cause.

Following a diagnosis of DCS the victim is required to undergo uncomfortable, expensive and time-consuming treatment and restrictions (for instance no-flying) are placed on his or her life for a lengthy period. The incident is also reported and used as scientific material on which future advice to divers will be based.
For both these reasons it would be helpful if suspected cases of DCS could be objectively confirmed.

The problem here is that there is only one definitive test for DCS. If you are experiencing pain that you believe is related to DCS, and you go into the chamber, if that pain is immediately relieved by pressure, the cause is bubble trouble, or DCS.

Joint pain, for instance, could have many causes, but instant (more or less) relief of joint pain under pressure is a positive indication that the cause was bubble trouble (in the diver, of course).

 

[chickdiver]

Actually- there is a more definitve test for DCS. Reference the article "Rethinking the Hit" by Andrea Zafares- you can find it in an old issue of Immersed- it should be on the website.

Basically (I was part of a study on this) DCS is a two fold issue. There is the physical blockage caused by expanding bubbles, as well as an immune system response. When the immune system responds- it treats the bubbles as it would any virus or bacteria. Lots of chemical signals are released teling the white blood cells what to do- some of these signals are known as "complements". The release of certain complements has been correlated to DCS via blood tests. Obviously this is a simplified version of the process, for a better one- check out the article referenced above.

Unfortunately- most physicians are not well versed in hyperbarics, and diving maladies specifically- therefor the standard for diagnosing DCS is also treatment for DCS- recompression therapy.

 

[Dr Deco]

Hello readers:

DCS Testing

There are not yet any tests for DCS though heaven knows people have searched for them for decades. [An early paper of mine on the subject is referenced below. You will note that the date is 1974.] It certainly would be nice to find a substance whose concentration changed (up or down) in the blood or urine following DCS. Where DCS is common, in altitude tests, a very large screening battery was run on hundreds of subjects with no positive finding.

The latest in this series was “complement.” The tests finally indicated only equivocal results. I am not surprised considering the experiments themselves. [This topic could not begin to be covered in the time I would have to write it.] Suffice it to say that in the latest incarnation of the Bennett and Elliott “Diving Medicine” book, the subject is no longer covered. A well-deserved burial, I believe.

There are people looking for biochemical “markers” with the hope that they will yield a method to modify the body and mitigate DCS. [I suspect that they are searching in the wrong place, but I am not the director of research at their institution.]

Doppler Testing

Doppler bubbles can be detected up to about 45 minutes after the dive in individuals with DCS. They can also be detected in individuals without DCS. The best Doppler indication is that no bubbles at all equates with no DCS, but that it only when you are constantly monitoring the decompression. That is not really useful for most divers in the field.

Pressure

The most reasonable alternative is a test of pressure. Generally the pain, or paralysis, will abate with pressure if it is soon after the appearance of the problem. This still requires a response from the individual however.

Dr Deco :doctor:

Readers, please note the next class in Decompression Physiology is September 10 – 11, 2005 :1book:
http://wrigley.usc.edu/hyperbaric/advdeco.htm


References :book3:

GF Doebbler, MR Powell, RW Hamilton, Jr. Biochemical indicators of decompression sickness. In: Proceedings: International Symposium on Blood-Bubble Interactions In Decompression Sickness, Toronto, August (1974).

MR Powell, GF Doebbler, RW Hamilton, Jr. Serum enzyme level changes in pigs following decompression trauma. Aerospace Med., 45, 519-524 (1974).

 

[BigJetDriver]

Actually- there is a more definitve test for DCS. Reference the article "Rethinking the Hit" by Andrea Zafares- you can find it in an old issue of Immersed- it should be on the website.

Unfortunately- most physicians are not well versed in hyperbarics, and diving maladies specifically- therefore the standard for diagnosing DCS is also treatment for DCS- recompression therapy.

Heather, et al,

The "science" in the Zafares article is extremely weak. (Note Dr. Deco's response above.)

The "Test of Pressure" is effective, as long as the problem is still in the bubble phase. If things have progressed to the cascade response phase, generally it is too late for pressure to affect bubble size, because they have become physical objects.

You are still correct about the weakness of most physicians when it comes to DCS, but it is not their fault. The system does not provide much time for it in their education.

 

[Saturation]

While there is no definitive test for DCS other than clinical evaluation, there is _one_ marker that is highly associated with AGE, total creatine kinase.

It has not received as much press as it should, but its a common lab test that can be an adjunct to examining the severity and later the resolution of AGE.

http://content.nejm.org/cgi/content/abstract/330/1/19


Since the test is innocuous and easily part of any blood panel drawn during an accident, it should be done and followed after _any_ DCS as it also suggest s a level of severity beyond a possible AGE component to a DCS 1.

 

[jfcl01]

You could also get an elevated CK from any muscle trauma, which is easy enough to get on a dive boat

 

[Tank Monkey]

Whie I undertand one would not want to undergo the large expense of chamber treatment, if it got to the point whereby I was sure enough of DCI I would rather spend a few years dodjing medical bills than risk the alternate option of doing nothing.
Remember we are not designed to breathe underwater and the fact that we do should be considered a privilage, one that should be respected. Take all the precautions your training has taught you to take and beyond that love the risk or leave the sport.

 

[fisherdvm]

You know, my sister insists on paying for nitrox on everydive. I think it is a waste of money. But you never know, one day, it might save her life. The same with some older diver I know who insists on a 5 minute safety stop.... Never know, one day, it might save his life too.... It never hurts to be conservative. Pushing the limit is for young and risk taking individuals.