An Automated External Defibrillator (AED) is a sophisticated, yet user-friendly, portable device designed to save the life of someone experiencing sudden cardiac arrest. This condition occurs when an electrical malfunction in the heart causes a dangerously irregular rhythm, preventing the heart from pumping blood effectively. The AED analyzes the person’s heart rhythm and, if necessary, delivers an electrical shock, or defibrillation, to stop the chaotic electrical activity and allow the heart to re-establish a normal rhythm. While AEDs guide the user with clear voice and visual prompts, specific safety precautions are paramount to ensure the shock is delivered effectively and that no one else is accidentally harmed.
Ensuring No Contact During Shock Delivery
The single most important precaution when using an AED is ensuring that no one is touching the patient during rhythm analysis and subsequent shock delivery. The electrical current, which is powerful enough to restart the heart, can travel from the patient to a bystander through direct contact. Accidental contact could cause the bystander to receive a shock, potentially leading to injury or inducing an irregular heart rhythm.
Before the AED delivers its electrical charge, the operator must verbally announce a “clear” command in a loud, commanding voice. This sequence, often taught as “I’m clear, you’re clear, everybody’s clear,” serves as a final warning for everyone nearby to step away from the patient and anything they are lying on. The operator must visually confirm that all responders and bystanders are clear before pressing the shock button on a semi-automatic AED or allowing a fully automatic AED to discharge.
If anyone is touching the patient during the analysis phase, the AED may fail to accurately read the heart’s electrical rhythm, potentially leading to an incorrect shock decision. If a person is in contact during the shock, the delivered energy may be diverted away from the patient’s heart and into the bystander. This diversion reduces the energy dose reaching the patient, decreasing the chance of successful resuscitation. The operator’s final visual check and loud announcement are the last line of defense to ensure the full therapeutic dose is applied solely to the patient.
Managing Environmental Hazards
The immediate environment requires careful attention to prevent electrical conduction and ensure shock effectiveness. The primary hazard is the presence of water, as it is an effective conductor of electricity. If a patient is submerged, they must be removed immediately and placed on a dry surface before using the AED.
If the patient is lying in a small puddle or on wet ground, they should be moved to a drier area if possible. The most immediate requirement is to thoroughly dry the patient’s chest before placing the electrode pads. Moisture on the skin can cause the shock to arc across the chest’s surface instead of passing through the heart, reducing effectiveness and potentially causing skin burns.
Metal surfaces like a grate or boat deck are generally safe because most modern AEDs are self-grounded. However, the AED pads must not be placed directly on or bridge over any metal objects. The AED should also not be used near flammable gases or liquids, as the electrical spark could ignite these materials. Although it is safe to use an AED on a patient lying on snow or ice, their chest must still be dried if wet.
Preparing the Patient for Pad Application
Before the AED can be used, the patient’s body must be prepared to maximize the electrical connection between the pads and the skin. Excessive chest hair prevents the adhesive pads from making solid contact, which is necessary for accurate rhythm analysis and shock delivery. To ensure effectiveness, the area where the pads will be placed should be quickly shaved using the razor typically found in the AED’s ready kit.
Any metallic objects, such as jewelry or underwire bras, that lie in the path of the electrical current should be removed or moved. Preparation also involves identifying implanted medical devices, like pacemakers or ICDs, which appear as a small bump or scar near the collarbone. The AED pads must be placed at least one inch away from these devices to prevent interference or damage. Finally, any transdermal medication patches must be removed from the chest area and the skin wiped clean, as the patch material could cause a burn when current passes through it.