An Automated External Defibrillator (AED) is a portable electronic device designed to save lives during sudden cardiac arrest. This serious medical condition occurs when the heart unexpectedly stops beating effectively. An AED works by analyzing the heart’s rhythm and, if necessary, delivering a controlled electrical shock to help restore a normal heartbeat. These devices are user-friendly, providing audio and visual prompts to guide even untrained individuals. Readily available AEDs in public spaces significantly increase the chances of survival.
The Problem with Touching Pads
A significant concern arises if AED pads are placed too close together or touch on the body. When the pads make contact, the electrical current delivered during a shock will follow the path of least resistance, which becomes the skin surface directly between the pads, rather than traveling through the heart. This “shunting” of electricity means the therapeutic shock bypasses the heart, rendering the defibrillation ineffective, as the heart’s abnormal rhythm remains untreated.
Touching pads can also cause localized skin burns where the pads meet. The concentrated electrical energy at the point of contact can damage the skin. Proper pad placement is important to ensure the electrical current effectively reaches the heart and to minimize potential harm to the patient.
Standard Pad Placement
For adults, the most common and effective method for AED pad placement is the anterior-lateral position. This involves placing one pad on the upper right side of the chest, just below the collarbone. The second pad is then positioned on the lower left side of the chest, several inches below the armpit and beneath the left breast tissue. This specific configuration ensures the electrical current passes directly through the heart, maximizing the chance of successful defibrillation.
Before applying the pads, ensure the person’s chest is bare and dry. Any clothing, jewelry, or excessive hair in the pad placement areas should be removed. Some AED kits include a razor or scissors to facilitate hair removal and clothing access, along with wipes to dry the skin. Proper skin preparation allows the adhesive pads to make full contact, which is important for delivering the electrical current effectively and preventing skin burns.
Another less common but acceptable placement for adults is the anterior-posterior method, where one pad is on the front of the chest and the other is on the back between the shoulder blades. This alternative can be useful in specific situations, such as avoiding medical implants like pacemakers.
Addressing Small Chests
When treating children or very small adults, the risk of AED pads touching is higher due to their smaller torso size. For children typically under 8 years old or weighing less than 55 pounds (around 25 kg), specialized pediatric pads are recommended. These pediatric pads deliver a lower, attenuated dose of electrical energy, which is more appropriate for a child’s smaller body.
If pediatric pads are not immediately available, adult pads can still be used, as delivering a shock is always preferable to no shock if an AED is indicated.
In such cases, the standard anterior-lateral placement might cause the larger adult pads to touch. To prevent this, an alternative anterior-posterior placement is used. This involves placing one adult pad in the center of the child’s chest and the other on their back, between the shoulder blades. This modified placement ensures the electrical current still traverses the heart effectively without the pads overlapping, maintaining the potential for a life-saving intervention.