# BP - Auscultation over Radial?



## icekayak (Apr 17, 2008)

Someone asked me a question today... 
They had a patient that couldn't bend their arm so had trouble getting the steth over the brachial artery and just put it over the radial artery and took the blood pressure by auscultation over the radial artery. 

Does anyone know how accurate this would be?


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## rmellish (Apr 17, 2008)

Did they have the cuff around the forearm as well?


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## Jon (Apr 17, 2008)

Why not palp it?


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## skyemt (Apr 17, 2008)

palp has proven to be relatively inaccurate...

in addition, large auscultory gaps can be missed using palp...

it's better than nothing, but not by a whole lot...


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## mikie (Apr 17, 2008)

During my ER clinical, a pt said we couldn't take her BP on her arms because of a double mastectomy (the reason why about the BP, I don't know), so I was told to use a child cuff over the wrist and take it same w/ as if Brachial


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## Ridryder911 (Apr 17, 2008)

mikie333 said:


> During my ER clinical, a pt said we couldn't take her BP on her arms because of a double mastectomy (the reason why about the BP, I don't know), so I was told to use a child cuff over the wrist and take it same w/ as if Brachial



You should have been taught this in your basic. Mastectomies as well as those of dialysis, CVA patients and some other conditions, cannot have a blood pressure as well as venous punctures performed on those extremities that is affected.

In radical mastectomies the lymph nodes is removed and vasculature is changed, the squeezing can cause damage as well as veinapuncture, from the lymph fluid. 

R/r 911


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## mikie (Apr 17, 2008)

Ridryder911 said:


> You should have been taught this in your basic. Mastectomies as well as those of dialysis, CVA patients and some other conditions, cannot have a blood pressure as well as venous punctures performed on those extremities that is affected.
> 
> In radical mastectomies the lymph nodes is removed and vasculature is changed, the squeezing can cause damage as well as veinapuncture, from the lymph fluid.
> 
> R/r 911



I never learned about the mastectomies related issues, so thanks for clearing that up.  We were however taught about the BP placement in dialysis and CVA patients.  

Thanks

-just for clarification though, auscultation over the radial does work, correct?


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## Jon (Apr 17, 2008)

mikie333 said:


> I never learned about the mastectomies related issues, so thanks for clearing that up.  We were however taught about the BP placement in dialysis and CVA patients.
> 
> Thanks
> 
> -just for clarification though, auscultation over the radial does work, correct?


Dialysis patients often have shunts... but why can't you get a B/P on a CVA patient? Active CVA, or S/P CVA? which side?


And Rid... c'mon... you KNOW that basics learn almost nothing in school... same as paramedics. Almost all of the useful stuff I've learned has been from co-workers, Con-Ed/conferences, and discussions in places like this.

Jon
- - - - - - - - PS... this is not a bash at BLS providers (I AM one)... just the sad truth. - - - - - - - -


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## Ridryder911 (Apr 17, 2008)

Here ya go.... Removal of lymph nodes may affect the drainage of lymphatic fluid from the arm on the surgical side. Problems with lymphatic drainage may result in arm swelling and an increased risk for infection from trauma to the arm. In addition, there is an increased risk for blood clots in the blood veins of the armpit because of surgical trauma in the area.... the same is true in patients with a CVA or immobile extremity. 

Dialysis shunts are a dangerous thing to place pressure on and as well hopefully no needles around the shunt..

R/r 911


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## icekayak (Apr 17, 2008)

Some interesting replies there thanks 
I didn't ask but i presumed they placed the cuff in the normal place. 

I guess as the artery is further away from the cuff there may be less defined sounds as the blood has more time to diffuse after passing through the cuff.. and i guess you would have to let the cuff down slower as it takes a fraction longer for the blood to reach the radial than the normal brachial?


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## Ridryder911 (Apr 17, 2008)

icekayak said:


> Some interesting replies there thanks
> I didn't ask but i presumed they placed the cuff in the normal place.
> 
> I guess as the artery is further away from the cuff there may be less defined sounds as the blood has more time to diffuse after passing through the cuff.. and i guess you would have to let the cuff down slower as it takes a fraction longer for the blood to reach the radial than the normal brachial?




Not really, as well you are not hearing the sounds of the brachial rather the radial, as well if the BP is to be taken on or at the radial, then the cuff should be placed on the forearm, so it is closer to the artery. 

R/r 911


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## Ops Paramedic (Apr 17, 2008)

With regards to your question on the accuracy, i don't believe it will be (as described, providing the cuff was placed superior to the elbow, and then auscultating over the radials).

There is a drop in BP by roughly 10mmHg when palpating/ausciltating the brachial artey vs that of the radial artery.  As for being able to ausciltate Korotkoff sounds over the radial artery, i would'nt know, and have not tried it yet.  I can only imagine that hey will be fairly diminshed, if at all audible.  If the cuff was placed just superior to the radial artery, then remember to change the size of cuff used as mentioned.

Hoping the info helped a bit...


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## icekayak (Apr 17, 2008)

Here's a piece from a AHA Scientific Statement (2005)
http://hyper.ahajournals.org/cgi/content/full/45/1/142 (Roughly half way down page)

It is taking about obese patients:
"In the rare patient with an arm circumference >50 cm, when even a thigh cuff cannot be fitted over the arm, it is recommended that the health care practitioner *wrap an appropriately sized cuff around the patient’s forearm, support it at heart level, and feel for the appearance of the radial pulse at the wrist. **Other potential methods for measuring radial artery pressure include listening for Korotkoff sounds over the radial artery*, detecting systolic pressure with a Doppler probe, or using an oscillometric device to determine systolic blood pressure; diastolic blood pressure is largely overestimated by both methods.156 The accuracy of these methods has not been validated, but they provide at least a general estimate of the systolic blood pressure."


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## Hastings (Apr 18, 2008)

It may be less accurate than more traditional means, but palpating at the radial is still going to be more accurate than trying to listen at the at the same location.


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## Ridryder911 (Apr 18, 2008)

Hastings said:


> It may be less accurate than more traditional means, but palpating at the radial is still going to be more accurate than trying to listen at the at the same location.



How is a palpation more accurate? When especially you are getting only an approximate systolic only?


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## TKO (Apr 18, 2008)

Here's another suggestion, grab your partner and a few others and practice it for yourself.  Check normally and then by palp, then move the cuff down to the forearm and check palp and auscultate.  Give a minute or two between efforts.

Then post your observed results here.


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## Kimmy Schaub (Apr 19, 2008)

Why didn't he use the unaffected arm? He could have just palpated it because placing the steth over the radial artery is not very accurate.


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## Ridryder911 (Apr 19, 2008)

Kimmy Schaub said:


> Why didn't he use the unaffected arm? He could have just palpated it because placing the steth over the radial artery is not very accurate.



Who says the radial artery is not accurate? Really folks, an arterial reading is an arterial reading. Where do you think they place art lines at? Remember, palpation is nice; but it is a only an educated guess of only what the systolic. 

R/r 911


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## MSDeltaFlt (Apr 19, 2008)

Not to mention there are three readings on a blood pressure that are important:

Systolic
Diastolic
Mean Arterial Pressure (MAP)

The MAP is more important than some may realize, and you cannot get it with a palpated BP.  NIBP's are not accurate.  They are only for trends.  The manufacturer's literature of the BP machine will tell you they're not accurate.  The only accurate BP's you can get are auscultated BP and a properly zeroed arterial line.

To calculate MAP is sys + dia + dia/3.  Will you have time to calculate that enroute to ER?  No.  But the ER will have the information at their disposal.

I personally don't like palpated BP's.  If your pt is so critical you don't have time to auscultate the BP then you only have time to palpate pulses; if and only if you're not "hung" further up on the ABC's.  

If they're HYPERtensive and critical, then you will need BOTH sys and dia BP's.  BP by palp is useless.  If your pt is HYPOtensive and critical, then you need to know where you can and cannot feel a pulse.  Again, BP by palp is useless; kinda like mammary glands on male swine.

Just my humble opinion.


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## mikie (Apr 23, 2008)

Another thing about the palp. vs. auscultation...

What about the pulse-pressure- you can't get that via palp.?  I recall learning about that, but not in enough detail.  Could someone give some more detail about it and its use for 'us' (prehospital providers)?


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## JPINFV (Apr 23, 2008)

MSDeltaFlt said:


> To calculate MAP is sys + dia + dia/3.  Will you have time to calculate that enroute to ER?  No.



If you can do math in your head, you should be able to. Add up the numbers as above and round to the nearest number divisible by 3. Remember that with numbers that are divisible by three, the sum of each individual number will also be dividable by three. For example, 153/3=51. 1+5+3=9 9/3=3. 

So, real life example:

126/74 MAP=(126+74+74)/3=274/3  Now, 2+7+4=13. 2+7+3=12 12/3=4. 272 is close enough to 273 for an approximation. So 273/3=91. MAP~91 (91.333 to be specific).

On the other hand, there's a second equation (same equation, actually, just shuffled around a bit).

PP/3+diastolic 

PP=Pulse Pressure= Systolic-Diastolic. Using the same example

(126-74)/3+74 = 52/3+74  Use the same technique to approximate a division by 3. 5+2=7. 7/3 is not a whole number. 6 is, so use 51. 51/3=17

17+74=91  Since you rounded down, the number is 91.333 if you want to be specific.

Decimals are actually pretty easy. If you round down a number, add 0.3333. If you rounded up, subtract 0.3333.


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## JPINFV (Apr 23, 2008)

mikie333 said:


> Another thing about the palp. vs. auscultation...
> 
> What about the pulse-pressure- you can't get that via palp.?  I recall learning about that, but not in enough detail.  Could someone give some more detail about it and its use for 'us' (prehospital providers)?




Pulse pressure is just simple the difference between the systolic and diastolic. Since you can't measure diastolic via palp, you can't calculate pulse pressure. PP is important in a variety of chronic and acute conditions involving the cardiovascular and neurological systems, with the well known example being the widening of PP in Cushing's Triad. Patients with arteriosclerosis will have a wide PP since the arteries will be unable to absorb the pulse energy like it should (smaller dicrotic notch). 

Heart diseases/conditions that decrease cardiac output (e.g.  CHF) will have a low PP.


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## AnthonyM83 (Apr 25, 2008)

MSDeltaFlt said:


> If they're HYPERtensive and critical, then you will need BOTH sys and dia BP's.  BP by palp is useless.  If your pt is HYPOtensive and critical, then you need to know where you can and cannot feel a pulse.  Again, BP by palp is useless; kinda like mammary glands on male swine.


Could you talk more about how knowing the diastolic will affect treatment for hypertensive and hypotensive patients?

I know it's useful for things like MAP and Cushing's, but as far as straight hypertensive and hypotensive patients, I'm a little lost. I can understand knowing diastolic just to know if they're hypertensive...


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## MSDeltaFlt (Apr 26, 2008)

http://www.highbloodpressuremed.com/blood-pressure-chart.html

Looking at the chart, you can see that it wouldn't take much to make any person clinically hypertensive.  There are many reasons that would cause a pt to be hypertensive.  Pain is one thing.  In a healthy person, there are two things that will change in ANY compromise:

HR
BP

The majority of us healthy people will show a rise in diastolic first.

Also, for those pts on multiple meds for multiple reasons (say cardiac), along with advance in years, you won't see a rise in HR.  You'll only see a rise in BP.  You always treat pain.

Also, on some high BP's are around 180 sys, but severe hypertension is  anything over 220 sys OR 130 dia.  The "or" is the operative word here. 

That's just a few reasons on the medical side.  What about traumas?

This is where you REALLY need both.

Unrestrained headon collision c/o chest pain.  You palpate the BP at 150/P.  What about the diastolic?  What if its 130?  Traumatic chest pain with BP = 150/130, I'm thinking cardiac tampenade until proven otherwise.

If there is anything else I can do, please let me know.


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## AnthonyM83 (Apr 26, 2008)

Thank you sir.

Anything on hypotensive?


Also, I once had a medic tell me the bottom number was more important. Why would that be? Is it really more important or does it depend on the situation and what you're looking for. I think his reasoning was that if you're diastolically hypertensive that's a lot of CONSTANT strain on your body. Would you guys agree?


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## MSDeltaFlt (Apr 26, 2008)

http://www.revolutionhealth.com/con...n=section_02&s_kwcid=ContentNetwork|971598174

I got the following from the above link.  I was looking on how to best phrase this, but they did such a good job I decided to let them do all of the talking.

"Blood pressure: How low can you go?
Current guidelines identify normal blood pressure as lower than 120/80 - many experts think 115/75 is optimal. Higher readings indicate increasingly serious risks of cardiovascular disease. Low blood pressure, on the other hand, is much harder to quantify.

Some experts define low blood pressure as readings lower than 90 systolic or 60 diastolic - you need to have only one number in the low range for your blood pressure to be considered lower than normal. In other words, if your systolic pressure is a perfect 115, but your diastolic pressure is 50, you're considered to have lower than normal pressure.

Yet this can be misleading because what's considered low blood pressure for you may be normal for someone else. For that reason, doctors often consider chronically low blood pressure too low only if it causes noticeable symptoms.

On the other hand, a sudden fall in blood pressure can be dangerous. A change of just 20 mm Hg - a drop from 130 systolic to 110 systolic, for example - can cause dizziness and fainting when the brain fails to receive an adequate supply of blood. And big plunges, especially those caused by uncontrolled bleeding, severe infections or allergic reactions can, be life-threatening."

There's a RN in the town I live in, and she enjoys freaking out the local nursing students when they take her BP because it normally runs 70/40 and she's asymptomatic and takes no routine meds.  If she's 90/60, she's stressed or pissed and hypertensive.

As far as which number is more important, it's all 3: Sys, Dia, and MAP.

Always listen to your patient, both figuratively and literally.  Keep your stethescope on you at all times.

Unless Vent or Rid can add anything, I believe that should cover it.  Let me know if it doesn't and I'll do my best to get you the information you need.


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