Vital sign findings with Thoracic/Triple A's

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DieselBolus17

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So I'm reading my text book and the text is very vague. States that there will be a B/P difference in each arm, accompanied with a HR difference (no kidding). My question is, for you guys that have had these Pt's, what is a typical B/P and HR difference of the upper extremities?
 
Nothing in medicine is concrete. Don't think of signs like these in terms of "will be" or "won't be." They're not always present, don't guarantee a diagnosis if they do exist, and certainly don't exclude a diagnosis if absent. The concepts of sensitivity and specificity come into play here again. Any finding (positive or negative) simply gives a practitioner more information to lean towards diagnosing one way or the other.

In cases of palpated pulse not matching up to the beating of the heart, make sure you differentiate HR vs. pulse. In this case, what you're feeling at the radial artery is a pulse, which may or may not correlate to the electrical activity of the heart itself (HR). The reasoning behind the possible differences in pulse findings and BP in each arm stems from the location of the various branches off the aortic arch and pressure changes depending on where the aneurysm lies and what vessels it encompasses. IIRC, there are various classifications for dissecting thoracic aneurysms (Type I, II, III perhaps?) that refer to where they occur. Also keep in mind that thoracic aneurysms may involve these kind of upper extremity variations, but abdominal aneurysms occur far enough after the aortic arch that they won't. They may affect the lower extremities similarly, but we don't check pulses or pressures there as frequently.

To conclude; I've never seen these variations in person. I've seen a few AAA and thoracic aneurysm patients, but they've either been so critical/dead I've had other concerns or I didn't know this was their problem at all. I do occasionally check BPs bilaterally on some patients as part of my assessment if dissection is on my list of differentials.
 
Ok, a few issues here.

First off, and most importantly, aortic dissections and AAAs are two different creatures. Different epidemiology, presentation, management.
  • Dissection involves the thoracic aorta, associated with Marfan's, hypertension
  • AAA involves the abdominal aorta, associated with smoking, older age, CAD.
(Yeah, there are thoracic aortic aneurysms, but they aren't common.)

Only a dissection will give you a difference in pulse strength or a difference in blood pressure. (The dissection can block off either of the subclavian or iliac arteries). Abdominal aneurysms don't do this - they just blow up.)

I'm not sure if the text really meant a "HR difference." It's really "can't feel the pulse in one arm or leg," or maybe just a little weaker.

It's really problematic to describe a "typical" BP difference in aortic dissection, since many dissections have no difference in BP between the arms, while many people without dissections can have a significant difference. For example, up to 20% of "normal" people have up to a 20 mmHg difference in BP between their left and right arms!
 
KellyBracket said:
Ok, a few issues here.

First off, and most importantly, aortic dissections and AAAs are two different creatures. Different epidemiology, presentation, management.
  • Dissection involves the thoracic aorta, associated with Marfan's, hypertension
  • AAA involves the abdominal aorta, associated with smoking, older age, CAD.
(Yeah, there are thoracic aortic aneurysms, but they aren't common.)

Only a dissection will give you a difference in pulse strength or a difference in blood pressure. (The dissection can block off either of the subclavian or iliac arteries). Abdominal aneurysms don't do this - they just blow up.)

I'm not sure if the text really meant a "HR difference." It's really "can't feel the pulse in one arm or leg," or maybe just a little weaker.

It's really problematic to describe a "typical" BP difference in aortic dissection, since many dissections have no difference in BP between the arms, while many people without dissections can have a significant difference. For example, up to 20% of "normal" people have up to a 20 mmHg difference in BP between their left and right arms!
Click to expand...

This explains a lot! Thanks!
 
KellyBracket said:
Ok, a few issues here.

First off, and most importantly, aortic dissections and AAAs are two different creatures. Different epidemiology, presentation, management.
  • Dissection involves the thoracic aorta, associated with Marfan's, hypertension
  • AAA involves the abdominal aorta, associated with smoking, older age, CAD.
(Yeah, there are thoracic aortic aneurysms, but they aren't common.)

Only a dissection will give you a difference in pulse strength or a difference in blood pressure. (The dissection can block off either of the subclavian or iliac arteries). Abdominal aneurysms don't do this - they just blow up.)

I'm not sure if the text really meant a "HR difference." It's really "can't feel the pulse in one arm or leg," or maybe just a little weaker.

It's really problematic to describe a "typical" BP difference in aortic dissection, since many dissections have no difference in BP between the arms, while many people without dissections can have a significant difference. For example, up to 20% of "normal" people have up to a 20 mmHg difference in BP between their left and right arms!
Click to expand...

Rampart this is Rescue 51, thanks for the tip!
 
The graybeards says that if you check all four extremities, most dissections (well, of a decent size I suppose) will have some pulse/BP differential between a couple of them. But you may have better things to do.
 
I've had quite a few disections and AAAs when I worked on CCT. I've seen it both ways, where they have high BP one arm and low in the other; but I've also seen it where they are just sitting there happy as can be no idea anything is wrong. I would usually try to get a BP in both arms if it was feasable though, just to check.

Its easier though, when you're told what's wrong with the patient rather than having to figure it out.
 
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