Understanding Optimal Defibrillator Electrode Pad Placement

Key Takeaways

• Electrodes, commonly referred to as pads, adhere to a patient's chest and connect to a defibrillator. Pad placement involves attaching two pads to a patient's bare chest to analyze a heart's rhythm, and, if necessary, conduct current to the heart.
• Both adult and pediatric electrodes come packaged with simple graphics that illustrate optimal positioning for current delivery. The American Heart Association (AHA) recommends two basic ways to position pads when treating adult victims: anterior-lateral (aka anterior-anterior) and anterior-posterior.
• The AHA recommends that any child under 8 years of age should be defibrillated using pediatric pads.
• Other important considerations include first ensuring complete pad adherence to the victim's skin, examining the victim's body for metallic items like medical devices and jewelry, and checking for excessive moisture and body hair that can interfere with or impede the delivered current.

The Importance of Optimizing Defibrillator Current Delivery

In sudden cardiac arrest (SCA), the heart stops beating in a productive manner and is unable to efficiently pump blood to the brain and other vital organs. Rescuers must shock the heart with enough current from an automated external defibrillator (AED) or manual defibrillator to interrupt the irregular activity and enable the heart to resume a normal cardiac rhythm.

Electrodes, commonly referred to as pads, adhere to a victim's chest and connect to a defibrillator. The pad enables the AED to analyze a heart's rhythm, and, if necessary, conduct current to the heart.

Careful pad placement and positioning create the most direct, unobstructed path of transthoracic current (TTC). Improper pad placement and positioning (including the presence of a variety of substances) can create resistance to current flow, also called transthoracic impedance (TTI). This guide explains pad placement and positioning, as well as other important considerations when defibrillating adult and pediatric SCA victims.

How to Position Electrode Pads on Adults

Both adult and pediatric electrodes come packaged with simple graphics showing positioning that will optimize the delivery of current. Electrode placement may vary by manufacturer: Be sure to review your electrode's instructions before you find yourself in a rescue situation.

In general, however, the American Heart Association (AHA) recommends two basic ways to position pads when treating adult victims: anterior-lateral and anterior-posterior.¹ Both arrangements enable the AED to analyze the victim's heart and deliver a shock if necessary:

Anterior-lateral Pad Positioning

When pads are positioned anterior-laterally, or front-side, one electrode is placed on the victim's upper right torso above the right nipple, just below the clavicle, and the other (lateral) pad should align with the bottom portion of the pectoral muscle on a male patient or under the breast on a female patient.





Anterior-posterior Pad Positioning

Position the posterior pad to the left of the spine, just below the scapula at the heart level. Position the front pad over the cardiac apex between the midline of the chest and nipple on a male victim or under the breast on a female.

How to Position Electrode Pads on a Child

Children suffering from sudden cardiac arrest are treated in the same fashion as adults, with one significant difference. Because children require less energy during defibrillation, the current delivered must be attenuated, or reduced, through the use of specially designed pediatric pads or by manually adjusting the energy on the defibrillator. For this reason, the AHA recommends that any child under 8 years of age should be defibrillated using pediatric pads.²

It is also important that electrodes don't overlap or make contact during defibrillation. A child's smaller physical size can make it a challenge to position both electrodes on the chest without any overlap. To ensure safe pediatric defibrillation, the best location for pads is the anterior-posterior (front-back) configuration. One electrode is placed on the front (anterior) chest wall and the other on the center of the child's back (posterior).

The AHA states that anterior-lateral placement or anterior-posterior positioning may be reasonable to defibrillate pediatric victims². However, ZOLL pediatric electrodes are designed to be used in anterior-posterior positioning, as shown in the images below. Attach the back pad along the center of the victim's spine. Attach the front pad over the cardiac apex between the midline of the chest and nipple.

Important Considerations for a Successful Defibrillation

In addition to appropriate pad size and position, there are other factors EMS and hospital clinicians need to consider when preparing to defibrillate a victim.

Above all, make sure that the pads completely adhere to the victim's skin. Air pockets or gaps between skin and the pads can lead to potential arcing and burns. To avoid this, apply one edge of the pad securely to the patient. Roll the pad smoothly from the applied edge to the other, being careful not to trap any air pockets between the pad and the skin.

Items on a victim's body can interfere with the delivered current — some can even impede it. To ensure the best possible outcome, pay close attention to the following list of personal items and attributes to help quickly prepare the victim prior to defibrillation:

Jewelry

Remove all of a victim's metal jewelry, including nipple piercings and necklaces, that may come in contact with electrodes.¹

Chest hair

If the victim has excessive chest hair, rapidly shave it with the razor provided with the AED before you apply pads to ensure proper adhesion. Those who are at risk for or who have already experienced SCA are encouraged to regularly remove chest hair.³

Breast tissue

Significant breast tissue can contribute to impedance. To overcome this, the AHA recommends placing the electrode beneath the tissue, using one hand to elevate the breast tissue and the other to apply the pad.³

Adequate pressure

Pad placement depends on adequate pressure. Studies have recommended that at least 80 N of force be applied when adhering pads to a victim, so it's best to press down as firmly as possible to ensure proper application.⁴

Defibrillator Pad Placement and Positioning FAQs

What are some common defibrillator pad placement mistakes to avoid?

Common defibrillator pad placement mistakes include failing to remove clothing or metal jewelry; ignoring skin moisture, which can severely reduce the efficacy of a lifesaving shock, placing pads over medication patches or pacemakers; using expired pads; and failing to shave heavy chest hair.

Are defibrillator electrode pads reusable?

No, AED pads are single-use only for actual emergencies due to the gel's adhesive and conductive properties, and must be replaced after any use or if expired.

Can adult defibrillator electrode pads be used on a child?

Yes, adult AED pads can be used on a child (under 8 years old or under 55 lbs) if pediatric pads are unavailable. The priority is to deliver shock therapy — adult pads are safe to use in an emergency. Ensure pads do not touch and reduce defibrillator energy level; if necessary, place one pad on the chest and one on the back.

Do you place defibrillator electrode pads over a pacemaker?

Defibrillator (AED) pads should never be placed directly over a pacemaker; pads should instead be placed at least 1 inch (or a few centimeters) away from the device to avoid damaging it or interfering with the shock delivery, while still enabling lifesaving treatment.

Is training required to place defibrillator pads?

No formal training is required to use AED pads in an emergency. These devices are designed for, and will guide, untrained bystanders: Once turned on, the AED provides voice prompts for pad placement, positioning, and operation. However, training is strongly encouraged to increase confidence and efficiency.

¹ Panchal AR, et al. Circulation. 2020;142:16:S366-S468.
² Topjian AA, et al. Circulation. 2020;142:16:S469-523.
³ Jacobs I, et al. Circulation. 2010;122:16:S325-S337.
⁴ Sado DM, et al. J R Soc Med. 2005;98:1:3-6.