For infants, AED pads should be placed in an anterior-posterior position: one pad on the front of the chest and one on the back. This front-and-back configuration is the standard recommendation because an infant’s chest is too small to fit both pads side by side without them touching or overlapping, which can prevent the shock from working properly.
Where Exactly the Pads Go
The front pad goes on the left side of the chest, over the heart area (the left precordium). The back pad goes behind the heart, just below the left shoulder blade. This positioning sends the electrical current directly through the heart from front to back.
The American Red Cross specifies this anteroposterior layout for infants and young children, and it’s the configuration recommended across major guidelines. The pads need at least 3 centimeters (roughly 1.2 inches) of space between their edges. On a small infant chest, the only way to achieve that separation is by placing one pad on each side of the body rather than both on the front.
Use Pediatric Pads When Available
Pediatric AED pads are designed to reduce the energy delivered to a level safe for small bodies. A standard adult AED delivers a much higher shock than an infant needs. Pediatric pads or a pediatric attenuator automatically lowers the energy output to around 50 joules, which is the starting dose for children under 8. Some devices then increase to 70 joules for subsequent shocks if needed.
For context, when medical teams use a manual defibrillator on an infant, they start at 2 joules per kilogram of body weight and go up to 4 joules per kilogram for follow-up shocks. The fixed 50-joule dose from pediatric AED pads is a simplified version of this approach, designed so bystanders can act without calculating weight-based doses.
What If You Only Have Adult Pads
If pediatric pads aren’t available, use adult pads. The American Heart Association is clear on this: an adult shock dose is better than no shock at all. The key concern with adult pads on an infant is overlap. If the pads would touch each other on the infant’s chest, place one pad on the center of the chest and the other on the center of the back, the same front-and-back approach used with pediatric pads.
Never let the pads make contact with each other. Overlapping pads can short-circuit the electrical current, sending it across the skin surface rather than through the heart.
Preparing the Skin
Before placing the pads, make sure the infant’s chest and back are bare, clean, and dry. Moisture weakens the adhesion and interferes with shock delivery. If the skin is wet from water, sweat, or any liquid, wipe it dry first. Remove any medication patches from the skin where the pads will go, as these can cause burns during a shock. Clean off any residue left behind by the patch before applying the electrode.
Timing With CPR
The 2025 guidelines from the American Heart Association and American Academy of Pediatrics recommend applying an AED immediately when one is available during infant cardiac arrest. Don’t delay to complete a set number of CPR cycles first. Turn the AED on, apply the pads, and follow the device’s voice prompts. The AED will tell you when to stop touching the infant so it can analyze the heart rhythm, and it will prompt you to deliver a shock if one is needed.
Between shocks, resume CPR right away. The AED will tell you when to pause again for another rhythm check. For infant chest compressions, the 2025 guidelines eliminated the old two-finger technique, which was found to be ineffective at reaching proper compression depth. The current recommendation is to use either a one-hand technique or the two thumb, encircling hands technique, where you wrap both hands around the infant’s torso and compress with your thumbs.
Step-by-Step Summary
- Turn on the AED and follow voice prompts.
- Expose the chest and back. Remove clothing, dry the skin, and remove any medication patches.
- Attach pediatric pads if available. Place one on the left front of the chest and one on the back below the left shoulder blade.
- Use adult pads if no pediatric option exists, placing one on the front center of the chest and one on the center of the back.
- Ensure at least 3 cm of space between pad edges. Pads must never touch or overlap.
- Stand clear when the AED analyzes the rhythm and when it delivers a shock.
- Resume CPR immediately after each shock, continuing until the AED prompts you to stop again or the infant shows signs of life.