# Line of demarcation with a PE



## Cindigo

Why? 

I can't think of what would cause this and my limited  internet search didn't help.

I know one of you brainy brains will know.


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## Medic Tim

To put it simply it has to do with perfusion. Hopefully this will steer you in the right direction.


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## Cindigo

I was thinking like Traumatic Aspyxia, but when you crush the body and blood squishes (that's a medical term right?) up, that makes sense. So when you have a embolism it blocks. So is it just that the backed up blood can't get back through and builds up? Is it a line like at the subclavian arteries? The friend I was chatting with didn't really give me a clear picture of where the line was, or if it was in the same place all the time. 

I know enough to know that I don't know enough. :wacko:


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## Medic Tim

Cindigo said:


> I was thinking like Traumatic Aspyxia, but when you crush the body and blood squishes (that's a medical term right?) up, that makes sense. So when you have a embolism it blocks. So is it just that the backed up blood can't get back through and builds up? Is it a line like at the subclavian arteries? The friend I was chatting with didn't really give me a clear picture of where the line was, or if it was in the same place all the time.
> 
> I know enough to know that I don't know enough. :wacko:



The line would be where the " injury" is. The proximal area is getting everything it needs to function properly. The distal area is either not getting enough or any.


Try to answer this. What would/ might happen if the pt received PPV? Would this benefit the pt?


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## Mobey

Medic Tim said:


> The line would be where the " injury" is. The proximal area is getting everything it needs to function properly. The distal area is either not getting enough or any.



What a horrible answer revealing your lack of knowledge in patho.

Blood leaves the right ventricle, into pulmonary circulation.
Leaves pulmonary circulation, into Left ventricle, then out to the body.

Sooo by you're patho, the right heart (proximal to injury-clot) is getting what it needs, but there is a clot preventing return to the Left heart, and that is going to somehow cause a line if demarcation in the external tissues of the body?? 

Please do not present yourself as an authority when clearly you have no idea what you are talking about.


The demarcation line in PE is not supported by science.


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## Cindigo

This was pretty helpful:

"Massive pulmonary embolism (i.e., a saddle embolism) creates increased
pressure in the pulmonary arteries, which is transferred into the right
ventricle (creating right ventricular strain). The right atrium also has
increased pressure. This is transferred to the superior vena cava, which
both the jugular and subclavian veins empty into. The pressure is so great
that it impedes capillary flow, which in turn impedes oxygen delivery and
finally tissue oxygenation -- hence you get hypoxia and cyanosis. It's
limited to the distribution of arteries/veins that empty into the subclavian
and jugular venous system, which explains the cyanosis from the nipple line
up.

Now, the question is why doesn't this affect the inferior vena cava and thus
cause cyanosis in the lower body as well? Well, in fact, it does cause an
increased pressure in the IVC. However, there is more capacitance in the
inferior venous system, the portal veins, and the splanchnic bed to allow
for more blood to accumulate there. The result is that tissue oxygenation
isn't compromised because the pressure doesn't accumulate so much that it
impedes capillary blood flow.

Of course this theory is not without problems. For one, one might ask why
doesn't the external limbs exhibit signs of edema associated with the
increased pressure? Unfortunately, I do not have a clear answer to that
question. It might be that the increased pressure in the venous system is
not that great, but when coupled with decreased cardiac output secondary to
decreased preload, might be significant enough to impede blood flow long
enough to compromise tissue oxygen delivery."

Way above my head at this point. But, incredibly inspiring for me to really sit down and study the cardiovascular/circulatory system in more detail.


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## STXmedic

What source did you pull this from?


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## Cindigo

ekg_club, a yahoo group. I did a search for "PE line of demarcation" it was one of the search results.


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## Cindigo

More specifically, it was in response to this thread in the ekg_club, a yahoo group:

http://health.dir.groups.yahoo.com/group/ekg_club/message/2292

Here's the response that I clipped those three paragraphs from:

http://health.dir.groups.yahoo.com/group/ekg_club/message/2308


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## Brandon O

The EKG Club is a great, great discussion list started by Nick Nudell and Tom Bouthillet. High-level discussion of the ECG and related topics by some of the best, and pretty newbie-friendly. I recommend joining and lurking. There's a Facebook group now too.


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## zzyzx

What an interesting discussion. There was a thread about this same topic in EMT City a few years ago, and the consensus at that time was that the "purple from the nipples up" thing was a myth; that it was nothing specific to PE's, just the effect of a big PE causing hypoxia and hypotension. But this discussion has me rethinking that. I wonder if anyone can provide references to published sources.


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## TatuICU

Well when the thrombus obstructs a pulmonary artery, or one of the branches it gives rise to, alveolar dead space increases so the area receives little blood flow to no blood flow at all even though its continuing to be ventilated (VQ mismatch).  And people forget that when this happens, that's not the end of the story.  Other substances get released from the clot and the areas affected that further exacerbate the vasoconstriction of regional vessels and the constriction of bronchioles.  So now we have an increase in pulmonary vascular resistance which just compounds the VQ mismatch.  So now with the increase is PA pressure the RV is screwed because its workload is increased to overcome the regional afterload in the PA. We're not far from RV failure at this point, then our CO/CI tanks along with our blood pressure, and subsequently we're now in shock.  So knowing that, you'd know that the physical signs and symptoms present like most other cardiopulmonary failure symptoms, SOB, chest pain, tachycardia, that "holy :censored::censored::censored::censored: I'm gonna die" feeling, diaphoresis, etc. But an actual line of demarcation? Maybe after they're already dead. 

Now, there are instances where multiple small embolis can get showered into into the pulmonary arterioles causing multiple pulmonary infarcts and subsequent ischemic necrosis of the area but that's fairly rarish i believe.  

Aortic dissections are the only events that i've actually seen a discernible line of discoloration and with the signs and symptoms that present with aortic dissections, they are often misdiagnosed as PEs. And the line of skin color and temp differentiation that presents with aortic dissections is no myth but of course depends on where the tear occurs at.

Would like to hear more from others on this as I've never looked for a line of demarcation as a physical symptom of PE.


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## ghettomedic

This came up in class the other day(medic school) and what we were told was that a line of demarcation secondary to a PE is a questionable subject due to most of the available information being based on opinion not fact. I would like to hear opinions on the issue so I have something to argue with my instructors.


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## systemet

ghettomedic said:


> This came up in class the other day(medic school) and what we were told was that a line of demarcation secondary to a PE is a questionable subject due to most of the available information being based on opinion not fact. I would like to hear opinions on the issue so I have something to argue with my instructors.



Let me start by saying that I'm not trying to be rude.  This is a good question, but let me quickly point something out.  Your instructors are emphasising that there's very little scientific evidence supporting the diagnostic value of a demarcation line for detecting PE, and they're saying that much of what is out there is based on opinion, instead of fact.  But you've come here to collect more opinions?  Just think about it a little.  

Maybe if one of us was a pulmonolgist, our opinion might be worth a little more, but most of what you get here is just going to be more of the opinion that your instructors are warning you againt.

Back to the opinion.  Based on my personal experience, which is worth next to nothing --- I only remember ever seeing demarcation lines on dead people. I understand how this finding can occur when pressure occludes venous return from the upper body into the SVC, and would suspect that this is more likely to indicate thoracic aortic aneurysm than a PE.  

I am certain I've missed many many PEs that ended up being clinically significant because we lack the diagnostic equipment necessary to identify all but the clearest presentations.

So, I don't think it's that likely that you'll see one on a live patient, although I'm sure if I went to pubmed.com, I imagine I could probably find an example.  This might be somewhere you could take a look for some case studies, or case series, maybe.  You may see them on dead people, and it might make you suspect PE, which doesn't change your management of the arrest, but it could also indicate another pathology.

If you find anything interesting, please let us know.


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## thisgirlisamedic

I can't remember the article but its in a pathologist study that most times it is dependent lividity ( did I spell that right lol ) due to the position of the pt from the rapid onset of the pe and like above stated is most comonly seen in dos pts and these are usually coroner cases, but i have also heard of a study on using this to have a valid cause of death without autopsy. Just a few thoughts but I'd live hear what anyone else has seen or heard since we often times due double duty as depty coroners. Lol forgive any spell mistakes my phone likes to put its two cents in


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