are all bubbles in the arterial side dangerous?

[perche]

Hello Dr Deco,

I know a diver that has many concern with ultrasonographic medium contrast (consisting of tiny bubbles), and more exactly with the word "bubble".

Sometime I'm not sure what kind of impact we got with WWW.

I believe they are many kind of ultrasonographic contrast medium (and "medical bubbles") depending what we look for: shunt, cardiologic field, vascular field ... or angeniogenesis of a lesion in the liver, breast,...

It seems to me the life of the bubble (at least in radiology) depends of the agents inside the bubble.... What about in the diving field?

It seems to me bubbles could have various size. So that even if we put the contrast agents through an i.v. line, depending of the size of the bubbles, these bubbles can go through the pulmonary capillary bed, and we can see the bubbles in the arterial side. This phenomena is not related to a FOP/shunt (whatever). Perhaps it's the same thing during the life of a diver?

Perhaps it's also the ultimate goal of the radiologist to find bubbles as contrast agent in the arterial side.... and he doesn't want hurt his patient (got a stroke).

At least in the normal radiological field (excluding cardiologic field) I didn't hear too much about any death related to cerebral injury and the use of ultrasonographic medium contrast.

Related to the above discussion could we have some additional comments about:
1) bubbles (any kind of bubbles) and risk of cerebral injury or heart infarcts
2)"medical bubbles" and "diving bubbles" related to tissular damage.

Are all bubbles in the arterial side dangerous?

Thanks in advance to clarify.

Best regards

 

[BigJetDriver]

Perche, et al,

Since Doc Deco has not yet joined us today, I will offer a couple of thoughts on this interesting subject.

As we know from doppler studies, there are bubbles running around in our blood stream all of the time caused by various things, such as cavitation from heart valves, and other forces. Divers, for instance, ALWAYS have bubbles after diving, sometimes a lot of them, in the circulatory system on both sides. If nothing else, we have bubble precursors, or micronuclei, at all times.

The problem is, of course, what size are they? As they get larger, they become problematic. The venous side, with the vey efficient lung-bed filtration, can handle more, and larger ones, than the arterial side, given of course the most immediate routing of that circulation to the brain.

Is there any study which shows exactly what size is safe on the arterial side, and above which trouble will occur? I will refer that to the good Doc.

 

[perche]

An additional comment:

There is a very very rare complication after a radiological procedure called "percutaneous pulmonary biopsy" (with cat-san) that is air embolism (seen 2 cases in 20y). In this peculiar case, it does mean air in arterial side! After this procedure we make always some slices to see if there is bleeding, pneumothorax,.... One time air was seen in coronary artery. Patient go to ICU but nothing happen. In the second case patient got a transient ischemic attack, but no "permanent clinical damage".

P.S.: If we can see air with ct scan we should not talk about one air microbubble....

To come back to the echographic medium contrast:

There are at least two kinds of medium contrast:
1) one has bubbles that do not go through the pulmonary capillary bed (like physiological serum, echovist(R),...). With this kind of contrast agent, if we see bubbles on the arterial side, we could think about a right-left shunt.
2) the other kind of echographic contrast can go through the pulmonary capillary bed and we can see bubbles on the arterial side. Perhaps one possible factor is the size? But generally nothing happens.
3) I believe bubbles have also various 1/2 life (medical bubbles, perhaps due to some various coating? )

We learn from diving course:
1) lungs are a good filter for bubbles
2) bubbles in coronary artery mean heart infarct

So that by now I'm pretty sure many people get confused.....

Could we say "a bubble is a bubble" ???

Schould we have fear from echographic contrast agent??? :07:

 

[BigJetDriver]

We learn from diving course:
1) lungs are a good filter for bubbles
2) bubbles in coronary artery mean heart infarct

So that by now I'm pretty sure many people get confused.....

Could we say "a bubble is a bubble" ???

Schould we have fear from echographic contrast agent??? :07:

Actually, we can say that a bubble is a bubble, but...and here is the rub....it is the SIZE of the bubble, and its LOCATION that make the difference in whether or not it causes a problem, or just fades away eventually.

ANY....I will say this again.....ANY procedure that introduces substances directly into the circulatory system has a certain amount of risk, but the introduction of contrast agents has been done so often and in such large numbers that we can say that the risk is quite low.

 

[perche]

Hello,

1) At least for some echographic contrast agent
bubbles can go through the lungs due to their size.

2) the concept of size and location
We all learn this concept: "bubbles in coronary, spinal, cerebral arteries -terminal arteries- provoke irreversible tissular damage".
however maybe the amount of bubbles is also important.
In addition a loss of cerebral function due to ischemia may be reversible for a short period after the insult and there is a place for therapy (in that sense this concept has evolved) - see cerebral ischemia / ischemic stroke.
Perhaps it's a reason to go quickly to the hospital (<<6 hours) after an accident.....

3) With doppler we can see bubbles from echographic contrast running around the arterial side for 5 minutes.

best regards

 

[Saturation]

BJ has said it well. Size and location matter. The amount of, or volume, is not a consequence so long as these individual bubbles do not coalesce to a larger size.

As to why, I think he made it clear that bubbles of very small size do exist in many conditions with diving. Its a concept integral to VPM theory.

 

[perche]

Hello Dr Staturation,

Thanks for the comments. I was a little surprize

Would you be so kind for me to answer to these questions:
1) What kind of bubbles (in terms of size and contents) can go through the lungs to tund around the arterial side
2) Does any bubble in the arterial cerebral circulation provoke always tissular damage (or from which size?)
3) And what about "silent infarct"?
4) why should not we perform HBO as precaution when decompression is not succesfully made ( at lest beyond a given limit ) ?
5) What should I answer to the diver that didn't want "bubble from echo medium contrast" in arterial circulation?


"The amount of, or volume, is not a consequence"
???

best regards

 

[perche]

Additional perfidious question: what is the relative frequency of injury for the following organs: Brain, Heart, Spinal cord, Intestine? and why (in terms of locations)?
after DI
Thanks and best regards

 

[miguel sanz]

very interesting cuestions, thanks peche.
One comment: the yatrogenic bubbles don&#180;t have an hipersaturated medium around to get bigger, that should have a relationship with your question, don&#180;t you think?
Ah! one more thing, I don&#180;t remenber how big are the pulmonary capilars, but the red cells pass through (deforming itselg a little) so for the bubbles to get to the arterial circulation without a shunt or a PFO tthey should be smaller than red cells (8 micras?) or maybe not if thay can strech and get through

 

[Dr Deco]

Hello perche:

Arterial Bubbles

There is no question that bubbles in the brain are a frightening thought. People are alarmed when they think that echocontrast bubbles are entering their brain.

There are many factors associated with embolic problems. When the embolizing entity is a blood clot, obstruction will occur when the vessel becomes small enough. With gas bubbles, other factors will play a role.

• How small are the bubbles initially? Contrast bubbles are typically about 10 microns in diameter or smaller.
• What is the total volume of gas in a given blood vessel? Short volumes are always pushed through to the venous side.

Many people have had contrast bubbles injected, apparently without deleterious effect, for many years. They pass into the venous return or are quickly absorbed [the brain is under saturated]. In addition, there is considerable collateral flow in the brain. This is very protective.

In studies I performed with Dr Merrill Spencer in the 1970s, we Doppler monitored the carotid artery of sheep along with the sagittal sinus. We found that the gas bubbles (from decompression) passed from the carotid artery and into the sagittal sinus after a couple of heartbeats. I suspect that many, possibly most, small bubbles will move through the brain capillaries.

There is also evidence from vascular surgery that many bubbles are detected (with transcranial Doppler) in the brain and neurological residuals do not result. This is not always the case, but bubble loads are often very large.

With decompression illness, the brain and cord can be embolized. The brain appears to be more susceptible to this problem. The blood clots, the cord appears to generally be spared. Other organs, e.g., muscle, fat, intestine, are resistant to hypoxia for longer durations and are not damaged. The heart appears to be affected only with large arterial bubble loads. Probably the contractions will expel small amounts. Large amounts will quickly cause problems from several pathways. This is why an ECG is not a useful tool for predicting DCS. When you see something (only seen with animals in a laboratory setting), the whole system is in cardiovascular collapse.

I personally would never hesitate to have contrast bubbles in my brain.:11:

Dr Deco :doctor: