popping bubbles?

[bada3003]

I saw a documentary on bubbles entitled "Pop! The Science of Bubbles" expecting to see a segment on decompression sickness. Well-made and lots of interesting stuff on the physics of bubbles and potential applications, but regrettably no mention of decompression.

But in one of the segments they discussed a medical application where bubbles would be used for drug transport and timed release. The idea is to introduce and then pop bubbles, when the time is right, by applying energy (i.e., vibration) to blood. Assuming size of bubbles is a significant contributing factor of decompression sickness, have there been studies to emulate the effect of recompression by trying to reduce the size of bubbles through popping them? Of course, doing so may have detrimental effects (increased bubble formation).

 

[Coztick]

I would hum Deep Purple's Smoke on the water at the safety stop if it was proven to help with off gassing.
I love simple solutions!

 

[DocVikingo]

Hi bada3003,

I discussed this issue on Scuba Doc's Scuba Clinic forum some years ago. Sadly, Dr, Campbell passed away and that board is no longer accessible.

You may find the following studies informative:

VIBRATION AND DECOMPRESSION GAS BUBBLES - Gravitational Physiology

Pre-Dive Vibration Effect on Bubble Formation After a 30-m Dive Requiring a Decompression Stop
http://www.uhms.org/images/DCS-and-AGE-Journal-Watch/germonpr__pre-dive_vibration.pdf

Regards,

DocVikingo

 

[bada3003]

Very interesting. The two studies suggest there may be no adverse effect, possibly a beneficial effect for reducing the likelihood of decompression sickness. On the surface counter-intuitive, but it seems consistent with bubble formation around impurities, microbubbles, and other "seeds."

But the two works seem to focus on preconditioning. What the documentary touches upon (timed release of drugs transported by bubbles that are popped on demand by vibration), and what I'm curious about, is "postconditioning." Especially since reaching recompression chambers incurs delays and in-water recompression has its own risks and limitations.

I do not know what frequencies are being used by (I assume still trial studies) the drug industry, but popping "larger" bubbles may require higher frequencies than ~25 Hz used in the "Pre-dive ..." paper. Instead of humming "Smoke in the Water," I'm speculating that humming a Led Zeppelin or Michael Jackson tune (maybe with the help of heliox deco gas) might be more targeted. Obviously low frequency waves pack more power but higher frequency vibrations may lead to more targeted popping of growing bubbles. All of this is purely conjectural.

Hi bada3003,

I discussed this issue on Scuba Doc's Scuba Clinic forum some years ago. Sadly, Dr, Campbell passed away and that board is no longer accessible.

You may find the following studies informative:

VIBRATION AND DECOMPRESSION GAS BUBBLES - Gravitational Physiology

Pre-Dive Vibration Effect on Bubble Formation After a 30-m Dive Requiring a Decompression Stop
http://www.uhms.org/images/DCS-and-AGE-Journal-Watch/germonpr__pre-dive_vibration.pdf

Regards,

DocVikingo

 

[DocVikingo]

But the two works seem to focus on preconditioning.

The first study appears focus on bubble formation during a hyperbaric exposure: "They were given a hyperbaric exposure at 250 kPa for 100 min in a hyperbaric chamber while performing an intermittent bicycle ergometer work of about 75 W."

The second indeed does focus on vibrational exposure prior to a hyperbaric exposure: "One of the dives was randomly preceded by a 30-min whole-body vibration session (frequencies 35-40 Hz) 1 h before the dive."

I am unaware of any research on the effects of vibrational exposure on DCS once it is manifest.

All of this is purely conjectural.

Amen, Brother Bada.

Cheers,

DocV

 

[bada3003]

The first study appears focus on bubble formation during a hyperbaric exposure: "They were given a hyperbaric exposure at 250 kPa for 100 min in a hyperbaric chamber while performing an intermittent bicycle ergometer work of about 75 W."

You are correct.

Upon fishing around for bubbles references, there seem to have been a flurry of recent works published in top venues such as Physics Rev. Letters. In one applied study, researchers were able to bridge the blood-brain barrier using microbubbles for drug transport using ultrasound that vibrates bubbles allowing them to wiggle through. That's a big deal.

It's my perception that research dollars in decompression sickness related research is modest (probably an understatement). With the basic and applied science that's being carried out in mainstream (i.e., well-funded) research fields related to bubbles, there may be an opportunity for researchers in dive science to adopt/apply some of the techniques.