An Automated External Defibrillator (AED) is a portable medical device designed to treat sudden cardiac arrest, a condition where the heart’s electrical activity becomes chaotic, preventing it from effectively pumping blood. This electrical malfunction, often ventricular fibrillation, requires a targeted electrical shock to reset the heart’s rhythm. Speed and correct application of the AED pads are fundamental, as the chance of survival decreases by approximately 10% for every minute defibrillation is delayed. The process demands careful preparation to ensure the current can successfully reach the heart muscle.
Essential Preparation Steps
The first action upon bringing the AED to the side of an unresponsive, non-breathing adult is to power the device on, which immediately activates voice prompts that will guide the user through the rescue sequence. If not already done, a call to emergency services (911 or local equivalent) must be placed immediately to mobilize professional help. Before placing the adhesive electrode pads on the person’s chest, the area must be prepared to ensure maximum skin contact and effective electrical conduction. This preparation involves quickly removing all clothing from the chest area, often requiring scissors found in the AED’s ready kit.
The skin must be clean and completely dry, as moisture, such as sweat or water, can conduct the electricity across the chest rather than through the heart, reducing the shock’s effectiveness and risking burns. If the adult has excessive chest hair, it should be quickly clipped or shaved using the razor found in the kit, as hair can prevent the pads from firmly adhering to the skin.
The Standard Adult Pad Placement
Adult AED pads use a standard anterior-lateral placement, ensuring the electrical current passes through the heart muscle. The two pads must not overlap, and specific locations are clearly marked with diagrams on the pads themselves. The first pad is placed on the upper right chest, just below the collarbone (clavicle) and to the right of the breastbone (sternum).
The second pad is placed on the lower left side of the rib cage, positioned slightly below the left breast or pectoral muscle, along the side of the body (mid-axillary line). This specific configuration ensures the electrical current is vectored across the greatest mass of the heart tissue. Applying the pads firmly to the skin is important for a strong adhesive seal, necessary for the AED to accurately analyze the rhythm and deliver a successful shock if advised.
Navigating Special Circumstances
Certain patient conditions require modifications to the standard procedure to ensure both safety and effectiveness. If the adult has an implanted medical device, such as a pacemaker or an implantable cardioverter-defibrillator (ICD), the AED pad must be positioned at least one inch (about 2.5 to 3 centimeters) away from the device. Placing a pad directly over an implanted device could damage it or block the delivery of the electrical energy.
Medication patches, such as nitroglycerin patches, must be quickly peeled off the skin before applying the AED pads, as the shock can cause the patch to explode or result in skin burns. If the person is lying in a wet environment or their chest is significantly wet, they must be moved to a dry area, and their chest must be dried thoroughly to prevent the electricity from short-circuiting or arcing away from the body. Metal jewelry or piercings in the pad placement areas should be quickly removed or moved, as metal is a conductor and can cause burns.
The Shock Sequence and Follow-Up Care
Once the pads are correctly and firmly applied to the chest, the pad connector is plugged into the AED, which begins to analyze the person’s heart rhythm. During this analysis phase, it is necessary that no one touches the person, as movement can interfere with the machine’s ability to accurately read the electrical activity. If the AED determines a shockable rhythm, such as ventricular fibrillation, it will charge and advise the user to deliver a shock.
Before pressing the shock button, the user must loudly announce “Clear!” to ensure all bystanders are not touching the patient. The shock is delivered by pressing the designated button, after which the machine will prompt the user on the next steps. Whether the shock was delivered or the AED advised no shock, the user must immediately begin high-quality chest compressions (CPR), following the AED’s voice guidance. The AED will continue to monitor the rhythm and prompt for re-analysis and additional shocks every two minutes until emergency medical services take over.