PFO and Smart-Com

[Web Monkey]

The Smart-Com has a range of settings from 1 - 5 that add additional deco stops and are supposed to reduce/eliminate microbubbles in people with PFO.

Is there any advantage to doing this for people without PFO?

Thanks!

 

[Dr Deco]

Dear Web Monkey:

Microbubble Suppression

This is a nice concept, but I do not see any data that it works. It is a derivative, however, from the concept that, if ascent rate is reduced, decompression bubbles growth is reduced. I would expect the reduced-rate-of-ascent mode to be of value but do not have quantitative measures of test results. :book2:

I would not be surprised if there were not any test results from the computer makers.

Decompression Microbubbles

Passage through a PFO is only one way in which gas bubbles can enter the systemic arterial circulation. Passage through the pulmonary vasculature is also possible when many bubbles are present. Thus, suppression in general is a good idea. Slow ascents are in the best interests of the diver.

Additionally, suppression of decompression bubble growth in the capillaries (where I believe the Doppler bubbles originate) will also suppress bubble growth in tissues (the cause of “the bends’). This later effect is true - and beneficial - whether you do or do not have a PFO . :mean:

Dr Deco :doctor:

Readers, please note the next class in Decompression Physiology :grad:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[Web Monkey]

This is great information! thanks!

Now for the probably non-answerable question

> Additionally, suppression of decompression
> bubble growth in the capillaries (where I believe
> the Doppler bubbles originate) will also suppress
> bubble growth in tissues (the cause of “the
> bends’). This later effect is true - and
> beneficial - whether you do or do not have
> a PFO .

Do you have any idea what level of supression would be useful/optimal in people without PFO? I was looking thought the docs on the vaious levels of supression, and it seems that selecting the maximum level leaves very little time to do anything except get to the bottom, then surface

Any ideas?

Thanks!

Dr Deco once bubbled...
Dear Web Monkey:

Microbubble Suppression

This is a nice concept, but I do not see any data that it works. It is a derivative, however, from the concept that, if ascent rate is reduced, decompression bubbles growth is reduced. I would expect the reduced-rate-of-ascent mode to be of value but do not have quantitative measures of test results. :book2:

I would not be surprised if there were not any test results from the computer makers.

Decompression Microbubbles

Passage through a PFO is only one way in which gas bubbles can enter the systemic arterial circulation. Passage through the pulmonary vasculature is also possible when many bubbles are present. Thus, suppression in general is a good idea. Slow ascents are in the best interests of the diver.

Additionally, suppression of decompression bubble growth in the capillaries (where I believe the Doppler bubbles originate) will also suppress bubble growth in tissues (the cause of “the bends’). This later effect is true - and beneficial - whether you do or do not have a PFO . :mean:

Dr Deco :doctor:

Readers, please note the next class in Decompression Physiology :grad:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[Dr Deco]

Dear Readers:

Microbubble Suppression

Of all of the work that has been performed on Doppler bubbles, it is generally agreed that they essentially do little with respect to DCS. This suppression of microbubbles in all divers is of little importance. There would most likely be a consensus among barophysiologists that Doppler Grades are not of overwhelming importance in DCS prognostication for an individual diver.

These venous bubbles only indicate a statistical relationship to DCS risk since they are not involved in DCS problems. You can inject air into your veins (do not really do this at home) and you will not get DCS. You will have trouble breathing if you inject too much, but you will not get the “bends.”

What the algorithm is doing is slowing the total ascent time. This will naturally serve to reduce the risk of DCS. However, over protection is of no particular value. Unlike “debits and credits,” you cannot store up decompression on one dive to be credited later.

What Setting?

I would choose a setting that reproduced the ascents of the other divers (e.g., with an Oceanic device) so that you all stay together.

Dr Deco :doctor:

Please note the next class in Decompression Physiology :grad:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[Web Monkey]

It's amazingly difficult to find clear, unbiased information on some decompression topics.

Thanks for the information, it's a big help, and you're providing a great service to the diving community!

Dr Deco once bubbled...
Dear Readers:

Microbubble Suppression

Of all of the work that has been performed on Doppler bubbles, it is generally agreed that they essentially do little with respect to DCS. This suppression of microbubbles in all divers is of little importance. There would most likely be a consensus among barophysiologists that Doppler Grades are not of overwhelming importance in DCS prognostication for an individual diver.

These venous bubbles only indicate a statistical relationship to DCS risk since they are not involved in DCS problems. You can inject air into your veins (do not really do this at home) and you will not get DCS. You will have trouble breathing if you inject too much, but you will not get the “bends.”

What the algorithm is doing is slowing the total ascent time. This will naturally serve to reduce the risk of DCS. However, over protection is of no particular value. Unlike “debits and credits,” you cannot store up decompression on one dive to be credited later.

What Setting?

I would choose a setting that reproduced the ascents of the other divers (e.g., with an Oceanic device) so that you all stay together.

Dr Deco :doctor:

Please note the next class in Decompression Physiology :grad:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[Dr Deco]

Thank you for the kind comment.

I am pleased to be of service.

Dr Deco:mean: