Twelve Tips for 12 Leads

Jacky Vaniotis, RN, NREMT-P

Services all across the state are getting in on the 12 lead excitement. Providers are taking 12 lead classes to learn to interpret cardiograms, talking to each other about axis deviation, ST segment elevation and contiguous leads. But before any 12 lead can be interpreted it needs to be obtained. And the tracing must be a good one for it to be meaningful. The following tips will help with the process of obtaining a good tracing.

1. Location, Location, Location

Look at any textbook that talks about obtaining 12 lead EKGs, and every single one of them will show you proper placement of EKG leads. So why, then, do we so often see patients with their V₁ and V₂ leads placed just below the clavicles, or V₄, V₅ and V₆ sitting on the patient’s abdomen?!

Remember, the electrocardiogram is looking at electrical activity moving from one pole to another, so if the leads are not placed where they belong, the tracing will not show an accurate representation of that activity!

2. Limb Leads

There is much disagreement in the literature about the best location for the limb leads. Some resources say they must be placed distally on the limbs (wrist and ankle), some say it doesn’t matter if they are distal or proximal as long as they are on the limbs. Some say they can be on the trunk as long as they are far enough from the heart. Some resources say it’s better to place the leads over bone because you get less muscle tremor, others say to place them over soft tissue and recommend that they not be placed over bone...

In general, however, the four limb leads should be placed on — guess what — the four limbs! You should place them on soft tissue, not directly over bones. The soft tissue of the medial surface of the calves and the meaty area in the middle of the forearm are ideal. (In situations in which you can’t, or choose not to, use those distal areas, for example, on a patient with Parkinson’s who can’t control his tremors, the best you might be able to do is to make sure that your limb leads, while on the trunk, are as close to the corresponding limbs as possible.)

3. Chest Leads

While there may be much debate about placement of the limb leads, there is universal acceptance that the placement of precordial (chest) leads is extremely important, and must be precise, correct and consistent. For example, if you want something that’s going to view the electrical activity moving toward the septum and anterior portion of the heart, you need to have your leads placed directly over the septum and anterior portion of the heart. So Leads V₁ and V₂ need to be placed at the fourth intercostal space, V₁ immediately to the right of the sternum and V₂ just to the left.

To find the fourth intercostal space for V₁ and V₂, start at the space just below the clavicle, which is the first intercostal space, and palpate down (yes, you must actually touch the patient’s chest!) to the second, third, then fourth space. Alternatively you could feel for the “bump” on the sternum, the angle of Louis, which sits at the second rib. Immediately lateral to the angle of Louis is the second rib, and just inferior to that is the second intercostal space; you can continue to count down from there.

You skip V₃ at this point, and place V₄ next. V₄ goes at the mid-clavicular line in the fifth intercostal space. Put your finger on the middle of the clavicle to get a sense of where the midclavicular line is. Now go back to where you put V₂ and move down one rib to the fifth intercostal space and follow that to the midclavicular line, then put V₄ there. (Don’t let anybody tell you V₄ goes just below the nipple line. While it may work for most men, in women nipple lines tend to migrate downward and outward as they age, and therefore the nipple line can’t be used as a consistent landmark!) Next, V₃ is going to go directly in the middle of the imaginary line between V₂ and V₄.

Again, you’re going to skip V₅ and go to V₆, which gets placed in the mid-axillary line at the fifth intercostal space. V₅ then goes directly in the middle of the line between V₄ and V₆, which just happens to be at the anterior axillary line.

One mistake many people make is to curve V₅ and V₆ upward toward the axilla, as if to circle around the breast like an underwire bra. This puts V₅, and especially V₆, too high for correct placement. V₄, V₅, and V₆ should all be in essentially a horizontal line.

Another mistake people make is to want to keep all the electrodes equi-distant from each other. Remember your landmarks, and you won’t fall into that trap.

4. Mama Mia!

Women, of course, present a bit more of a challenge than men do because of their breast tissue that often gets in the way. You do need to remove a woman’s bra, and lift her breast out of the way in order to place the stickies, especially V₄ and V₅. If you are uncomfortable about touching her breast, or afraid of making her uncomfortable when you do so, you might try placing a sheet across her upper chest before you begin placing the leads, then you can lift her breast up with the sheet as a barrier between your hand and her skin. Other suggestions are that you ask the woman to lift the breast herself, or use the back of your hand, instead of your palm, to lift the tissue.

The question always comes up as to whether V₄ can be placed on top of the breast tissue itself, or whether the breast must be lifted for placement of the electrode directly onto the chest. As a general rule, you should place the sticky on the chest wall, not on the breast tissue, as breast tissue tends not to stay in one place if the patient should move.

5. Keep it Clean!

The patient’s skin needs to be clean, dry and free of lotions, powders, and sweat. This takes on more meaning when you consider that the patients we’re seeing, many of whom are having chest pain, may also be diaphoretic. Remember, also, that a lot of elderly patients have very dry skin, especially on their lower extremities, and their dry flaky skin will prevent the electrodes from sticking. Also, a lot of patients use lotion to counteract their dry skin, and that lotion will interfere with the ability of the electrodes to stick.

Start by seeing if the electrodes will stick without any special treatment. If they do, then you’re good to go. If they don’t, try cleansing the skin briefly with an alcohol prep pad. In addition to removing some of the dry skin flakes and cleansing away the lotion, vigorously rubbing with the alcohol pad for a few seconds (then letting it air dry) will abrade the skin slightly and further enhance the contact surface.

Oh, and make sure you’re not putting the stickies on over the patient’s nylon stockings! Take a minute to remove them before applying the electrodes! (Don’t laugh. It happens more than you know!)

6. Gorrilla Syndrome

The patient’s skin also needs to be free of hair that interferes with electrode contact. This doesn’t mean you need to shave every man you do a 12 lead on. If the patient’s chest is hairy, you may still be able to get away without shaving it (and the patient will be grateful a week or so from now!) Unless there is an excessive amount of hair, or it’s very thick, long, or curly, you might be able to just part it with your fingers and get the electrode to stick to the small area of now-exposed skin.

If all else fails, you will need to shave the hair. Make sure you have already established where the stickies need to go. And remember, your shaved area is like your signature — if you placed the electrodes incorrectly, all the world will know it because of the incorrectly-placed little bald spots you left behind!

7. First Things First

It’s often helpful, particularly with a fidgety patient, to put the chest leads on first. If you put the limb leads on first and the patient moves his arms or crosses his legs while you’re putting the chest leads on, you’ll find yourself having to go back and reattach those electrodes he knocked off in the process.

8. Look at the Patient, Not the Monitor!

Don’t forget the basics. As with single lead monitoring, if you see a flat line, but your patient is talking, you know the problem is the machine not the patient. If you get a flat line but you know your patient is not in asystole, check your equipment. Begin at the patient and check that you have attached a clip securely to each of the 10 electrodes you have placed on the patient (one on each of the four limbs and six across the chest). A clip that has inadvertently come off will usually be the cause of a lead not reading. If that doesn’t solve the problem, then check your machine and make sure your lead pack wire is plugged securely into the machine. Then check that each lead wire is plugged securely into the lead pack. Then follow each lead to the patient and confirm that the clip is securely seated into the wire.

9. Provide support.

The key to getting an artifact-free cardiogram is a movement-free patient. If the patient has to be using muscles to hold her head up, you will see artifact. Place the patient as close to flat as she can tolerate. Provide a pillow and have the patient rest her head on that pillow. You may need to reposition her in order to allow her head to rest comfortably. Some patients might need more than one pillow to fill the space.

Similarly, make sure patients don’t have to be using their own muscle strength to hold their arms up. If the person is especially thin, she might be able to rest her arms comfortably beside her body on the stretcher, but most of our patients spill over the stretcher sides. You might ask the patient to sit on her hands in order to keep them on the stretcher without having her have to use her muscle strength to keep them up. If that doesn’t work, you may need to do some creative strapping to include and fully support the entire length of the arms so the patient’s muscles don’t have to do any work.

10. Sit! Stay!

Ever notice how often elderly people are holding onto a tissue or handkerchief? Ever notice how usually they are fidgeting with that tissue or handkerchief? Artifact! Ask the patient if you can hold the tissue momentarily (or have the patient put it on his chest) during the EKG acquisition. You will be amazed at how many times that simple change will take you from an artifact-filled tracing to a clear one.

Many times when you instruct the patient to lie as still as he can, you still get artifact. A quick look at the patient finds him with clenched fists and pointed toes, in his attempt to lie as still as he can, just as you requested. Instructing him again to relax his muscles often falls on deaf ears, as he thinks he already is relaxing! Try reaching down and gently shaking his arms just a tiny bit, then doing the same with his legs; this will often help him release the tension long enough that you’ll be able to get a better tracing.

Don’t forget electromagnetic interference, either. If you find that your patient appears to be lying still and relaxed, yet you still see artifact (especially 60-cycle interference), consider the possibility that the problem is the electrical equipment around you, including lighting, your portable radio, a cell phone, an automatic blood pressure machine, or even the wires from the EKG machine itself. Try turning off and/or unplugging non-essential equipment, uncrossing or repositioning leads going to the patient, or, if necessary, moving the patient to another location to do the cardiogram.

11. Whose Cardiogram Is It, Anyway?

If you want your cardiogram to be accepted by the emergency department staff and placed into your patient’s chart, you must put some patient identification on it. Whether your machine allows you to enter the name or whether you write it on the EKG by hand, be sure that you identify it as your patient’s. You should document his name, date of birth and/or MEMS state run sheet number, and the date and time of the tracing. Don’t just leave it unlabeled at the patient’s bedside when you drop the patient off, because that will quite likely cause it to end up in the wastebasket later on because nobody can be certain which patient it belongs to. It’s also a good idea, if you have time, to mount it onto an 8 1/2 by 11 sheet of paper so that it won’t fall out of the record at some point because it’s a different size from everything else.

12. Explain What You’re Doing While You’re Doing It.

Just because doing 12 leads has become old hat to you, it may not be such a routine matter for the patient. And also remember that field 12 leads are a relatively new phenomenon, and a lot of patients might not be expecting to have one done outside a hospital or doctor’s office. Take the time to talk to the patient while you are applying the leads. “Have you ever had an electrocardiogram/EKG/12 lead done?” “It takes a picture of the electrical activity going on in your chest, but it doesn’t put any electricity into you.” “I’m going to put 10 stickies on you, one on each of your arms and legs and six across your chest.” “The most important thing you can do to help make this test come out accurate is to lie as still as possible.” For you, who have seen dozens of these done, there is no mystery, but your patient will most likely appreciate the explanation.

Summary

Your prehospital EKG is the earliest cardiogram that the physician has on the patient. It may be the only EKG obtained while the patient has pain, because while you did the 12 lead you provided oxygen, put the patient at rest, and maybe gave nitro and morphine or fentanyl, and the patient might be arriving at the hospital pain-free. Make sure that this earliest cardiogram is the best quality it can be!