Proper AED pad placement is essential for ensuring that the defibrillator works correctly in the case of sudden cardiac arrest. It also helps to prevent undue harm to the patient. Correct AED pad placement varies between children and adults, though, and some unique situations require adjustments to the general rules.
Adult Pad Placement
Your defibrillator kit should tell you where to place the AED electrode pads on adults via audio prompts and visual diagrams. However, the general rule is to position one AED pad over the upper right side of the patient’s chest and the other on the left side of the rib cage, below the armpit. This creates a pathway through the heart muscle that permits the device to shock the heart.
AED Pad Placement on an Infant
Infants under one year old are more likely to have a cardiac arrest due to an airway obstruction[mfn]ahajournals.org[/mfn] or respiratory disease than a problem with their heart. One common mistake, though, is to confuse a choking emergency with cardiac arrest. So observe the baby carefully, and if they aren’t clearly choking (in which case apply choking measures first) and an AED is available: give CPR, call the emergency services, and apply the AED.
Using a set of child AED pads or the child setting to adjust the energy level for a pediatric patient, place one pad in the center of the baby’s chest and the other in the center of the baby’s upper back. If only adult pads are available, place them in the same two places, ensuring that the pads don’t touch each other. If there are no pediatric pads available, it is better to use adult AED pads on a baby[mfn]pubmed.ncbi.nlm.nih.gov[/mfn] than do nothing at all.
Child Pad Placement
Children from one to eight years old and/or individuals who weigh less than 55 pounds (25kg) should be treated with pediatric pads, if available[mfn]ncbi.nlm.nih.gov[/mfn]. Just as with an infant, place one pad in the center of the child’s chest and the other in the center of the child’s upper back. Make sure that the pads don’t touch.
The main difference between children and infants is the technique for applying cardiopulmonary resuscitation. For a baby, use only two fingers of one hand (pointer and middle), or both thumbs. For a child, use one hand or two hands, depending on the size of the child. In both cases, press down to ⅓ of the depth of the child’s chest and watch the chest rise to allow the heart to fill with blood before pressing down again. Rescue breaths should only be attempted if you have been trained in CPR.
Defibrillator Pad Placement on a Pregnant Woman
If a pregnant woman goes into cardiac arrest, it is essential to perform CPR and use an AED if one is available. An international multidisciplinary expert consensus statement published in 2023 states that “defibrillation can be lifesaving when applied in urgent circumstances and should not be withheld because of concerns of pregnancy or fetal harm[mfn]sciencedirect.com[/mfn].” If the mother doesn’t make it, neither will the fetus—unless first-response measures are taken immediately.
To use an AED on a pregnant woman, place one pad above her right breast and the other pad laterally on the left side of her rib cage, both on bare skin. CPR should also be performed as normal for an adult patient, with no modifications. If the patient revives, place her on her left side to increase blood flow to the heart and fetus.
When calling 9-1-1 for the attention of a pregnant patient, make sure you tell the operator about her state. If the pregnancy is advanced and the mother dies, it might still be possible to save the baby via an emergency C-section.
AED Pad Placement for Cardiac Arrest Victims with a Pacemaker
Pacemakers are small devices that help some heart patients maintain a normal heart rhythm. While pacemakers can help to treat arrhythmias, they do not regulate fibrillation. If someone with a pacemaker goes into cardiac arrest, it is both necessary and safe to use an automated external defibrillator.
First, locate the position of the pacemaker. Usually, it is installed in the upper left side of the patient’s chest. In this case, there is no need for modification, so apply one pad to the upper right side of the chest and the other to the lower left side of the chest, on the left side of the patient’s rib cage as normal. If the pacemaker is installed in the upper right side of the patient’s chest, place the first pad at least one inch below or to the side of the pacemaker and the second pad on the left side as described.
Anterior-Lateral vs Anterior-Posterior Pad Placement
As we’ve seen, the two basic positions for AED pad placement are:
- Anterior-posterior or “anteroposterior” AED pad placement: One on the front and one on the back
- Anterior-lateral or “anterolateral” placement: One on the right side of the chest and one on the lower part of the left chest wall (or a few inches below the left armpit, over the ribcage)
Anterior-posterior placement is usually used on children, and anterior-lateral placement is usually used on adults. However, an anterior-posterior placement can be used on adults as well with a slightly different pad placement. Instead of placing the automated external defibrillator pads on the center of the chest and back, place one pad just below the left nipple and the second pad on the left side of the back, directly below the scapula (informally known as the “wing bone”).
Special Situations
There are a few basic steps you’ll need to follow beforehand if your patient has a hairy chest, a medicated patch, or wet skin. We explain these situations in more detail in our article on special considerations when using an AED.
Hairy Chest
If the patient has a lot of chest hair, the pads might not stick to their skin properly—jeopardizing the electric shock. Before placing the pads on the patient, use a razor to shave the hair where the pads will be placed. Most AED first responder kits include razors.
Wet Patient
Electricity and water do not mix, and neither should water and an AED. If the patient is wet, put them on a dry surface, remove their wet clothing, and get the chest dry before applying the pads.
Medicated Patch
AED pads should not be placed on top of a medicated patch, because the patch could make the electrical shock less effective[mfn]ncbi.nlm.nih.gov[/mfn]. Before applying the pads, carefully remove the patch (wearing gloves) and quickly wipe the area with alcohol or a towelette.
If in Doubt, Follow the Manufacturer’s Instructions
While there are a few things to keep in mind, AED pad placement will follow only one of two patterns—front and side or front and back. In both of these cases, the most appropriate position for the AED pads will be illustrated on the pads themselves and all you need to do is follow the electrode pad placement instructions.
The main considerations for placing AED pads are to avoid a pacemaker or medicated patch and ensure the pad is placed on dry, bare skin. Also, remember that an AED should only be used in cases of a cardiac arrest emergency. If the patient is unconscious and not breathing normally, go ahead and deploy the automated external defibrillator. An AED shock coupled with chest compressions and early activation of the EMS system could be the victim’s best chance of survival.
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