# Taking automatic BP's on the forearms/legs



## zzyzx (Oct 19, 2012)

Does anyone know of any information regarding the accuracy of taking automatic blood pressures on the forearm of a patient, or on the thigh or lower legs?


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## rescue1 (Oct 19, 2012)

I've seen it taken, but I have no idea if the value would be different.


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## NYMedic828 (Oct 19, 2012)

I do it from time to time for obese patients. Never used a leg but forearm plenty of times.

I don't see why it would be any less accurate. An automated cuff isn't looking for a sound like we are when we auscultate a BP. It is much more finely sensing when bloodflow returns to the brachial artery. The brachial artery does split at the elbow joint into the ulnar and radial arteries but they are so close together at that height I don't see it causing any variation in the pressure.

In the case of using a leg over an arm, you are using much more distal extremity. The reading could be influenced by the pressure gradient of arm/leg being substantially different distances from the heart. (the difference is probably all of 10mmHg, not too clinically relevant, its better than not obtaining a BP at all...)


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## Akulahawk (Oct 20, 2012)

While you may get a different value by using a forearm or a leg than you'd get if you used the upper arm, what _I_ am more concerned with is the trend. The trend will often tell you how the patient is doing over time. A single BP won't concern me that much, however vitals trending in a given pattern might be quite obvious and very concerning.


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## VFlutter (Oct 20, 2012)

Akulahawk said:


> While you may get a different value by using a forearm or a leg than you'd get if you used the upper arm, what _I_ am more concerned with is the trend. The trend will often tell you how the patient is doing over time. A single BP won't concern me that much, however vitals trending in a given pattern might be quite obvious and very concerning.



It is very dependent on patient's individual anatomy and disease but for most situations just pick a site that works, document it, and keep using it. Just use common sense, if your patient has extensive PAD then the calf/ankle may not be the most accurate.


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## hogwiley (Oct 20, 2012)

I check BP at my job continuously all night long. Sometimes I might have 15 patients who are q4 vitals for a 12 hour shift, plus a couple post surgical or unstable patients who have them far more often. Sometimes Ill take BP on the wrist or forearm for various reasons, usually because of IV lines or you have a bariatric pt. Ill also use the leg because of upper extremity trauma, for some pediatric patients, or because a doctor wants BP checked on all 4 extremities.

From what Ive been able to tell, you get a slight decrease using a forearm, and slightly more using the wrist, but probably not enough to matter for EMS purposes. Not as sure about the legs, although when I check all 4 extremities I usually dont see any difference between arms and legs unless there is some cardiac or circulatory issue.


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## hogwiley (Oct 20, 2012)

I check BP at my job continuously all night long. Sometimes I might have 15 patients who are q4 vitals for a 12 hour shift, plus a couple post surgical or unstable patients who have them far more often. Sometimes Ill take BP on the wrist or forearm for various reasons, usually because of IV lines or you have a bariatric pt. Ill also use the leg for some pediatric patients or because a doctor wants BP checked on all 4 extremities.

From what Ive been able to tell, you get a slight decrease using a forearm, and slightly more using the wrist, but probably not enough to matter for EMS purposes. Not as sure about the legs, although when I check all 4 extremities I usually dont see any difference between arms and legs unless there is some cardiac or circulatory issue.


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## Akulahawk (Oct 20, 2012)

ChaseZ33 said:


> It is very dependent on patient's individual anatomy and disease but for most situations just pick a site that works, document it, and keep using it. Just use common sense, if your patient has extensive PAD then the calf/ankle may not be the most accurate.


While the individual readings may not be accurate, as long as you're using the same site, you shouldn't see much in the way of variability from reading to reading, as long as the patient remains stable. Now most people won't have much difference in BP values taken at the upper arm, forearm, wrist, calf. They may not be identical, but should be relatively close. PAD could, of course, alter a reading at a specific site but if you're taking BP readings at the same site, the PAD shouldn't alter a person's BP reading on it's own over a period of a few minutes to an hour. If you're seeing wild swings or a worrisome trend in vital signs during the time period that you have the patient and you're using the same site, something else is wrong, not the PAD in that particular limb. I might want to confirm a worrisome trend by taking serial BP's at another site.

That being said, if I'm using a site _other_ than the upper arm, I'm going to document that.


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## mycrofft (Oct 21, 2012)

*Hi Z!*

Remember automated BP machines are not very good with very irregular pulses, (irregular strength, rythm, or both).


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## cusadiz (Nov 2, 2012)

Next time you do a checkout, take your own on the upper arm and then forearm/leg. Note any similarities/differences. Maybe even do it a few days in a row.


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## krtemt (Nov 3, 2012)

When I did my clinicals at the end of October we had to us a patients lower leg to take her bp. The RN had my place the cuff right above the ankle on the patient.


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## CritterNurse (Nov 5, 2012)

I once took my blood pressure with a small veterinary cuff on my thumb. It was only a couple points away from my normal blood pressure reading. I didn't think to double check it with my human-sized cuff at the time though.

I think the 'upper arm' is the ideal spot to put the cuff, but they do work in other locations. Just have to remember to document where you put the cuff.


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## Brandon O (Nov 5, 2012)

Note that difference between an ankle and brachial BP (the ankle brachial index) is considered an indicator of PVD.


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## Summit (Nov 8, 2012)

^Good info



Akulahawk said:


> While you may get a different value by using a forearm or a leg than you'd get if you used the upper arm, what _I_ am more concerned with is the trend. The trend will often tell you how the patient is doing over time. A single BP won't concern me that much, however vitals trending in a given pattern might be quite obvious and very concerning.



This is what I came here to post. 

There's plenty of patients I've had where the only suitable place for a BP was one forearm... or one leg... (injuries, ports, IV/PICCs, wounds (surgical, ulcers, trauma), etc. 

I do size my cuff and I do verify a pressure now and then by auscultation or palp to make sure the machine is not way off. Truly, it is about the trend for most patients.


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