An automated external defibrillator (AED) is a portable medical device designed to treat sudden cardiac arrest by delivering an electrical shock to restore a normal heart rhythm. AEDs use voice prompts and visual cues to guide rescuers, making them accessible to the general public. Although AEDs are designed for straightforward use, certain circumstances require specific modifications to the standard protocol to ensure effectiveness and safety. Understanding these special considerations maximizes the chances of a successful rescue.
Preparing the Patient for Pad Placement
Effective defibrillation requires direct, firm contact between the electrode pads and the patient’s bare skin so the electrical current successfully passes through the heart. Moisture, excessive hair, or medical patches on the chest can compromise this critical connection.
If the patient’s chest is wet from sweat, rain, or water from a pool, the area must be quickly wiped dry before applying the pads. Water can spread the electrical current across the skin’s surface, reducing the amount of energy that reaches the heart muscle and decreasing the shock’s effectiveness.
Excessive chest hair prevents the adhesive pads from sticking properly, which can result in an electrical arc and potentially cause small burns. If the AED kit contains a razor, the hair should be quickly shaved from the pad placement areas to improve conductivity. If no razor is immediately available, one technique involves firmly applying the first set of pads and quickly ripping them off to remove the hair, essentially using them as a wax strip before applying a fresh set of pads for the shock.
The chest area must also be checked for transdermal medication patches, such as those containing nitroglycerin, pain medication, or hormones. These patches can block the flow of electricity or heat up during the shock, causing thermal burns. The patch must be removed with a gloved hand, and the skin wiped clean to eliminate residual medication before the AED pads are applied. Jewelry should only be removed if it lies directly where a pad is placed or if it is a large metallic item that could interfere with the electrical path.
Addressing Environmental Hazards
The patient’s immediate surroundings must be assessed to ensure rescuer safety and defibrillation efficacy. If the patient is lying in standing water, such as a large puddle or on a waterlogged floor, they should be moved to a dry location before the AED is used. Although modern AEDs are designed to be self-grounding, water conducts electricity, and moving the patient minimizes the risk of the electrical charge dispersing across the surface.
If the patient is lying on a conductive metal surface, such as bleachers or a metal deck, defibrillation can still be performed safely without moving them. The American Heart Association notes that large metal surfaces generally pose no shock hazard to the rescuer or the victim, provided the pads are not directly touching the metal. The primary safety rule remains that no one should touch the patient during the shock delivery, regardless of the surface they are on.
Rescuers must also ensure sufficient room to operate the AED and perform cardiopulmonary resuscitation (CPR) effectively. Confined spaces can hinder the ability to deliver chest compressions correctly or to place the AED pads in the optimal position. Clearing the immediate area of unnecessary equipment or bystanders creates a safer and more efficient environment for the rescue effort.
Using the AED on Children and Patients with Implants
The standard AED protocol requires modification when the patient is a young child or has an implanted medical device. For children under the age of eight or weighing less than approximately 55 pounds, pediatric-specific pads should be used if they are available. These pads incorporate an attenuator, which reduces the energy level of the electrical shock delivered to the child’s smaller body.
If pediatric pads are not immediately accessible, standard adult pads should be used rather than delaying the life-saving shock. Since the pads may touch if placed in the standard adult position on small children and infants, an alternative configuration is necessary. Rescuers should use an anterior-posterior placement, with one pad placed on the center of the chest and the other placed on the back between the shoulder blades.
Patients who have an internal pacemaker or an implantable cardioverter-defibrillator (ICD) require special consideration for pad placement. These devices are typically visible as a small, firm lump or bulge, often located beneath the skin near the collarbone. To avoid damaging the implanted device or interfering with the shock, the AED pads must be placed at least one inch away from the location of the pacemaker or ICD.
The presence of an implanted device does not prevent the use of an AED, as the priority is always to restore a perfusing heart rhythm. Similarly, using an AED on a pregnant patient is not contraindicated, and the immediate need to save the mother’s life takes precedence. For both patients with implants and pregnant patients, rapid deployment of the AED remains the most important factor for survival.