Detecting bubbles after dive

[lowviz]

I feel your pain.

I feel YOUR pain. I lost all the databases for med and engineering that I knew so well. I so loved the modern search engines. (I cut my searching teeth in the late 60's on Science Citation Index. Pencil and paper and a LOT of library time.)

Now: Top 11 Trusted (And Free) Search Engines For Scientific and Academic Research | Emerging Education Technologies

 

[Duke Dive Medicine]

Hello, I'm a med student with a lot of interest in diving medicine.
I was wondering if anyone ( Maybe Dr. Deco) has experience in detecting venous bubbles with ultrasound systems?
Can I use a vascular ( no image, just sound) ultrasound to detect bubbles after a dive? I don't really have the money to purchase a $3000 portable doppler ultrasound( Yet ).
I know they are designed to measure flow but can a computer "translate" the signal to bubble quantification?
Any help is appreciated!

Hello @A_Buhlmann ,

Have you looked at the science around diving and venous gas emboli? There's been a lot of work done over the years in this area. What in particular were you looking to examine?

Best regards,
DDM

 

[A_Buhlmann]

Hello @A_Buhlmann ,

Have you looked at the science around diving and venous gas emboli? There's been a lot of work done over the years in this area. What in particular were you looking to examine?

Best regards,
DDM

Hello! Yes I did some searching in medical databases about the use of doppler technology since the 70's, with the grading systems that are greatly dependent of operator experience. More current research uses at least 2D echocardiography with Doppler.
I was wondering if "simple" available devices such as a vascular (acoustic only) doppler would be able to reach the ventricles and/or aorta (which I know are not part the venous system). Where I live, I don't have access to a 5MHz device, which theoretically has more tissue penetration and less "resolution".
I'm looking to examine venous bubble production after various dives profiles plus any arterial "bypass" which could in theory provoke AGE.

 

[A_Buhlmann]

I am not sure if you know what exactly you want to study in relation to the venous bubbles, but if you have a hypothesis, you can come up with a grant proposal and see if DAN or one of the other diver related companies will cover the costs of the more expensive equipment and maybe a trip or two to an exotic location to study divers

That would be a dream job! I'm only a med student yet, I don't think they would let me do a lot of research( specially paid ones ) Thanks anyway

 

[A_Buhlmann]

Yes, most likely. Make sure that what you are looking at has an analog output.

Remember that 10MHz has an even shallower 'detection' penetration than 8 MHz. Honestly, I doubt that it matters.
Compare the specs, call the company. You could also look for someone who is a good a LabVIEW programmer to really help you out. Team efforts rule.

Lots of us use LabVIEW for apps that require sensing external analog variables. Sadly, once I retired, my 'seat' stayed with the company. I can no longer generate stand-alone programs...

Yes it has more shallow tissue penetration, do you think I could reach the ventricles with that frequency?
between med school and the pandemic I guess I'm going to have to wait to form a team.

 

[Duke Dive Medicine]

Hello! Yes I did some searching in medical databases about the use of doppler technology since the 70's, with the grading systems that are greatly dependent of operator experience. More current research uses at least 2D echocardiography with Doppler.
I was wondering if "simple" available devices such as a vascular (acoustic only) doppler would be able to reach the ventricles and/or aorta (which I know are not part the venous system). Where I live, I don't have access to a 5MHz device, which theoretically has more tissue penetration and less "resolution".
I'm looking to examine venous bubble production after various dives profiles plus any arterial "bypass" which could in theory provoke AGE.

I don't know that a standard vascular doppler has the kind of penetration that you'd need to reliably hear bubbles within the ventricles. The ones I have experience with are touchy enough with arteries that are close to the surface. Duke has used the Techno Scientific DBM9008 and DBM9610 models for acoustic-only diving research.

Best regards,
DDM

 

[lowviz]

Just guessing, no. There would be a tremendous amount of 'heart noise' and I suspect that a lower frequency probe might be better or even a second good second way to observe (by comparison).

That would be most interesting to watch in real-time on a spectrum analyzer...

 

[A_Buhlmann]

I don't know that a standard vascular doppler has the kind of penetration that you'd need to reliably hear bubbles within the ventricles. The ones I have experience with are touchy enough with arteries that are close to the surface. Duke has used the Techno Scientific DBM9008 and DBM9610 models for acoustic-only diving research.

Best regards,
DDM

Thanks for all the help!
I guess I'll try to find a 5MHz device or just buy a imaging device( not in the near future though$$$$)
The devices you said(Techno Scientific DBM9008 and DBM9610 ) are kind of expensive right?
Which diving medicine book do you recommend most? I'm a fast learner and I would like a good reading about it
Best Regards!

 

[A_Buhlmann]

Just guessing, no. There would be a tremendous amount of 'heart noise' and I suspect that a lower frequency probe might be better or even a second good second way to observe (by comparison).

That would be most interesting to watch in real-time on a spectrum analyzer...

The spectrum analyser would be the best option. I was researching a decent phone app that I could do that in real time just after the dive...
Thanks for the help!

 

[lowviz]

IMHO, you as a doctor (someday), will be all about your ability to observe without bias. I spent years managing and mostly just working in a technical (electronics, machining, glassblowing) medical research support team.

Yes, it is possible for one to both manage and be part of a team. You just need a good team or you are pooched. You know when you have a good team when everyone shares emerging ideas and there are no 'glory hounds' or 'us-vs-thems' to poison the mix. Just get rid of those or suffer endlessly. Everybody equally shares success.

Observing:
I learned from a neuroscientist (that I was helping) that listening to a complex signal is often extremely informative. Any cardiologist would most likely agree with that. I could see the single neuron trace on an oscilloscope or a spectrum analyzer but when turned into an audio signal tremendous nuances were easily apparent. Each tool has a use, all of them together in real-time are powerful.

Throw your programmer a bone: TableCurve2D and 3D. https://systattasoftware.com/products/tablecurve-3d/ They are stupidly easy to use. Just fill out the X vs Y, or X vs Y,Z table and hit 'Simple Equations'. It will turn your observations into a function or a surface. So much easier to program a function than construct a look-up table. Ron Brown wrote those programs long ago, since lost touch with him...