An Automated External Defibrillator (AED) is a portable device designed to deliver an electrical shock to the heart, restoring a normal rhythm during sudden cardiac arrest. The heart’s electrical activity becomes chaotic, preventing it from pumping blood effectively. The electrical current from the AED momentarily stops this disorganization, allowing the heart’s natural pacemaker to reset. Placing the electrode pads correctly and rapidly is important, as the chance of survival decreases significantly with every minute of delay. Proper pad positioning ensures the electrical current travels directly through the heart muscle.
Patient Preparation Before Pad Application
Before applying the electrode pads, the patient must be prepared to ensure optimal adhesion and electrical conductivity. The chest area where the pads will be placed needs to be completely bare, requiring the removal or cutting of all clothing. Any moisture, such as sweat or water, must be quickly wiped away. Water is an electrical conductor that can scatter the energy and potentially cause burns on the skin.
Excessive chest hair may prevent the pads from sticking securely to the skin. Many AED kits include a small razor to quickly shave the area, ensuring firm, direct skin contact. Additionally, any metallic jewelry, particularly necklaces, that might interfere with the electrical pathway should be removed. This includes jewelry within an inch of the pad placement area.
Standard Adult Pad Placement
The standard method for adults is the anterolateral placement, which creates the most direct pathway for the electrical current to pass through the heart. This positioning requires one pad to be placed on the upper right side of the chest, just below the collarbone and to the right of the breastbone. This location is often referred to as the right infraclavicular area.
The second electrode pad is placed on the lower left side of the rib cage, typically along the mid-axillary line, below the left nipple or breast tissue. This lower placement ensures the pad is positioned on the side of the chest wall. The electrical current travels diagonally from the upper right pad, through the heart, and exits through the lower left pad.
The two pads must not touch each other. Contact would cause the electrical charge to short-circuit across the surface of the chest rather than passing through the heart. Placing the pads according to the diagrams printed on the packaging helps maximize the chance of successful defibrillation.
Addressing Special Placement Considerations
In certain circumstances, the standard anterolateral placement needs modification. If a patient has an implanted medical device, such as a pacemaker or an implantable cardioverter-defibrillator, the pads must be positioned with care. These devices usually appear as a small bulge under the skin, most often on the upper chest.
The AED pad should be placed at least one inch away from the visible bulge or scar of the implanted device to prevent damage and ensure the electrical energy reaches the heart. If the patient is wearing any transdermal medication patches, they must be removed with a gloved hand and the skin wiped clean. Applying a pad over a patch can block the current transfer and may cause skin burns.
If the patient’s chest anatomy or an obstruction prevents the standard front placement, an alternative technique called anterior-posterior placement can be used. This involves placing one pad on the center of the chest and the other pad on the patient’s back, positioned between the shoulder blades. This front-and-back positioning allows the electrical current to pass through the heart muscle.