# Where do you put the limb leads?



## Aidey (Feb 11, 2011)

This came up the other night with my fairly green EMT B partner, who was commenting on how picky I was about lead placement. During the conversation he mentioned I was the only person he had worked with who liked the limb leads to be put in specific places, and also I was the only one who consistently put them were I do. 

Now, I knew I was a bit more OCD than most of my coworkers but this was pretty alarming to me. So I'm curious where you guys place your leads, how picky you are about them being there, and why you put them where you do.

For the current/recent Paramedic students, what are you being taught about lead placement?


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## Icenine (Feb 11, 2011)

Not a medic but Brady Emergency Care 11 say's

Mid-clavicular just inferior and "lower chest" which according to the pictures is just inferior to the bottom of the ribs and mid-clavicular

OR

"On the limbs"

My Partner like them at them inferior to the hips and distal to the shoulder cuff.  I usually do ankles and shoulders with the occasional wrist depending on clothing and c/c.


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## TransportJockey (Feb 11, 2011)

I tend to use wrists and ankles, but I've used the modified trunk positions before, mainly when I worked inhospital.


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## Aprz (Feb 11, 2011)

In class, I always putted it on the shoulders and ankles.


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## Shishkabob (Feb 11, 2011)

I really have no specifics MOST of the time, and alternate between trunk and limbs (whichever is easiest at the time), however I typically put near the shoulders and on the ankles... I find I get the best, least "artifacty" looks that way.

Though I do put them on the wrist at times too, especially for the cardiac related patients.


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## GClarkes (Feb 11, 2011)

*Limb leads for a reason?*

I've always placed them "on the limbs"..I know as my career progressed they always move closer and closer to the torso. Unless you have a very tremulous patient, I find they work better on the limbs, over soft tissue or muscle (not bone). However, the greatest source of artifact, or poor pick up on the monitor seems to be electrode gel issues..Even with a brand new bag of dots, the gel seems to cause most of the troubles.

my two cents worth for a Friday. Have a safe weekend everyone.

Greg


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## STXmedic (Feb 11, 2011)

I always put mine on the limbs, shoulders and lateral thighs preferably. A co-worker actually did a study on this exact topic, that he may or may not be working on publishing. He ran 100 12-leads on 50 pts. One 12-lead with electrodes on the torso, one with them on the limbs. What he found was while it didn't affect the ability to determine STE, it did affect QRS morphology and axis. Just food for thought...


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## emt_irl (Feb 11, 2011)

i learned how to place both on the limbs and the torso.

im not sure why but i trust the lead placement on the chest more so then the limbs as there is far less movement and artifacts on the rythm strip.

on the limbs in put them over the radial artery where youd take a pulse, and on the medial/inside ankle. ive had horrible problems with poor quality electrodes in the past, mostly with the gel and the adhesive pad. our serivce has finally setteled on the brand ambu dots


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## JPINFV (Feb 11, 2011)

PoeticInjustice said:


> I always put mine on the limbs, shoulders and lateral thighs preferably. A co-worker actually did a study on this exact topic, that he may or may not be working on publishing. He ran 100 12-leads on 50 pts. One 12-lead with electrodes on the torso, one with them on the limbs. What he found was while it didn't affect the ability to determine STE, it did affect QRS morphology and axis. Just food for thought...



Of course now we've come to the crux of the issue. Are we talking about putting the limb leads on the limbs for a 12 lead or just for continuous cardiac monitoring?


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## STXmedic (Feb 11, 2011)

JPINFV said:


> Of course now we've come to the crux of the issue. Are we talking about putting the limb leads on the limbs for a 12 lead or just for continuous cardiac monitoring?



For just determining rhythm, I see no problems with the torso. But if there's the potential of then moving from a 3-lead to a 12-lead, why bother messing with new limb-lead electrodes. If you put them on the limbs initially, you have no problem transitioning between the two modes. That is, of course, if you are of the frame of mind that the limb leads do in fact need to be placed on the limbs for acquisition of a 12-lead.


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## Veneficus (Feb 11, 2011)

JPINFV said:


> Of course now we've come to the crux of the issue. Are we talking about putting the limb leads on the limbs for a 12 lead or just for continuous cardiac monitoring?



I don't think this is a significant issue, if you had a quadamputee, you would have to use the modified torso placement anyway.


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## TomB (Feb 11, 2011)

It is a significant issue because the decision to send a patient to the cardiac cath lab sometimes comes down to fractions of millimeters (not to mention that for every health care professional who really knows the Mason-Likar modified lead placement there are 10 more who just throw the leads on the torso and don't really care).

Here are two cases where lead placement was a critical issue.

The first is a 23 year old male who was seen at a VA clinic for chest pain.

http://ems12lead.com/2010/03/24/23-year-old-male-cc-chest-pain/

At the VA clinic they placed the leads on the patient's chest which pulled the frontal plane axis to the right and inverted the T-wave in lead aVL. This was just enough to trigger the ***ACUTE MI SUSPECTED*** message from the GE-Marquette 12SL interpretive algorithm.

You will note that when the EMS crew arrives and places the leads properly the message does not appear.

The second case is a 72 year old male CC: Unknown problem (man down)

Part I
http://ems12lead.com/2010/02/06/72-yom-cc-unknown-problem-man-down/

Part II
http://ems12lead.com/2010/02/14/72-yom-cc-unknown-problem-man-down-conclusion/

In this case it was the EMS crew that placed the leads on the patient's chest (data quality was also lacking).

The end result was a "false positive" STEMI Alert which was, fortunately, canceled by the ED physician.


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## Veneficus (Feb 11, 2011)

Tom,

I know that you know more and are considerably more interested in electrophysiology than I am. 

But I have to say. If cath labs are activated or not because of a machine interpretation of STEMI, there is a failure that is bigger than the lead placement. Especially on a 23 year old without some very specific history.

Based on the amount of angio I have been exposed to, both diagnostic and interventional, the clinical presentation needs to weigh in as well as electrophys findings. Fractions of millimeters seems to me like a trip to the cath lab is not a bad idea anyway.


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## TomB (Feb 11, 2011)

The bottom line is that placing the limb leads on the chest can change the frontal plane axis and it can do things like invert the T-wave in one lead or another. If that lead happens to be lead aVL and there happens to be marginal ST-elevation in the inferior leads, it could make someone's spider sense tingle (or cause a disparity between "today's" ECG and the "old" ECG). If it was your (mother, father, brother, sister, spouse, child) we were talking about would you want lazy lead placement to enter the calculus?


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## Veneficus (Feb 11, 2011)

TomB said:


> it could make someone's spider sense tingle (or cause a disparity between "today's" ECG and the "old" ECG). If it was your (mother, father, brother, sister, spouse, child) we were talking about would you want lazy lead placement to enter the calculus?



Phrased like that, no.

But if by history or clinical presentation, if there was absoultely any doubt, I would want the cath to be absolutely certain. Especially on the older members of my family. (who would probably benefit from it now)


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## TomB (Feb 11, 2011)

I agree with that! The idea of someone not getting reperfusion therapy scares me more than a cath that shows clean coronaries.


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## Icenine (Feb 11, 2011)

Now you need to tell us where you want them, you said you were specific and if it makes a difference you have the opportunity to teach.


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## reaper (Feb 11, 2011)

Always thought it was pretty obvious " Limb Leads"???


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## 8jimi8 (Feb 11, 2011)

Aidey said:


> This came up the other night with my fairly green EMT B partner, who was commenting on how picky I was about lead placement. During the conversation he mentioned I was the only person he had worked with who liked the limb leads to be put in specific places, and also I was the only one who consistently put them were I do.
> 
> Now, I knew I was a bit more OCD than most of my coworkers but this was pretty alarming to me. So I'm curious where you guys place your leads, how picky you are about them being there, and why you put them where you do.
> 
> For the current/recent Paramedic students, what are you being taught about lead placement?



I put them in the anatomically correct positions.  For *diagnostic 12 lead* I learned very precise anatomical rules.  The limb leads go on the wrists and ankles.  Then I circle them with black sharpie, so after the electrode fairy gets antsy we can tell where they were originally placed and every ecg after the original is actually comparable to the baseline.

For *bedside monitorin*g,  The limb leads just have to be on the limbs, just make sure that the lower limb leads and the ground are below the ribs NOT on them.


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## socalmedic (Feb 11, 2011)

I put the limb leads on the "limbs" however bicep/forearm/wrist I make no differentiation as long as the leg leads go to the same corresponding spot. eg bicep/quads, forearm/calfs, wrist/ankel. i have seen qrs changes when you mix positions such as deltoid/ankel, or arms/ABD. i rairly place the limb leads on the chest, one of my books states that as long as the limb leads are 10cm away from the heart it makes no difference, i buy that though. i will throw the reference up if any asks when i get home.


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## 18G (Feb 11, 2011)

I always put them on the chest. Mainly because it reduces artifact in the field with patient's who want to be moving their arms all around. I think this is the premise for this common placement. 

Technically, they are supposed to be placed on the limbs. For 12-leads I try to remember to place the limb leads on the limbs since this is where the hospital places them for their 12-leads. It has been said that some variation can be had on the ECG if electrodes are placed differently on different acquisitions (ie pre-hospital places on chest, hospital acquires on limbs = variation in waveforms). 

The majority place limb leads on chest from my almost 20yrs of experience. 

I can't imagine electrodes on the ankles would work out too well pre-hospital and would think the wires would be off more then on.


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## 8jimi8 (Feb 11, 2011)

18G said:


> Technically, they are supposed to be placed on the limbs. For 12-leads I try to remember to place the limb leads on the limbs since this is where the hospital places them for their 12-leads. It has been said that some variation can be had on the ECG if electrodes are placed differently on different acquisitions (ie pre-hospital places on chest, hospital acquires on limbs = variation in waveforms).



quoted just to emphasize whomever's idea I adopted about circling your original electrode placement in sharpie.  It just leaves a better trail when you have the patient who requires serial ECGs.


You also have to remember the purpose of your monitoring.  If you are simply watching a rhythm, chest placement is fine.  

If you want DIAGNOSTIC quality, you need to place them correctly.  (general you)


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## systemet (Feb 20, 2011)

The electrodes for the limb leads need to be roughly equidistant from the center of the heart.  

This is necessary for generating the appropriate negative electrode for the augmented leads e.g. (aVL negative pole = RA + LL; aVR negative pole = LL + LA, aVF negative pole = RA + LA).  This is also required to produce an accurate wilson's central terminal (RA + LA + LL) for generating precordial leads.  

If, for example, the electrodes are placed on the deltoids and the ankles, the signal from the LL electrode will be weaker versus the signals from the RA and LA electrodes.  This will distort any lead that uses the LL electrode (II, III, aVL, aVF, V1-V6, i.e. basically everything).

If the electrodes are going to be placed on the chest, or on the shoulders, then the corresponding ground and LL electrodes need to be on the torso or upper thighs.

If there's a big enough infarct, poor placement might not affect the ST segment enough to alter treatment.  But in marginal cases it could be critical.  It's best if a system has one standard for landmarking for all 12-leads, and that this is the same standard used by local hospitals.  This way old ECGs can be compared to the EMS tracing.

All the best.


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