An Automated External Defibrillator (AED) is a portable medical device designed to treat sudden cardiac arrest (SCA), often caused by an electrical malfunction in the heart. SCA causes the heart to beat irregularly or stop pumping blood, leading to death within minutes without intervention. The AED delivers an electrical shock to reset the heart’s rhythm, which is the only definitive treatment for the most common causes of SCA. Immediate action using an AED and cardiopulmonary resuscitation (CPR) significantly increases survival, as the chance of survival decreases rapidly with every minute defibrillation is delayed.
Immediate Actions and Activating Emergency Services
The initial response involves quickly assessing the environment for hazards to ensure rescuer safety. Once the scene is safe, check the collapsed person for responsiveness and normal breathing. An individual who is unresponsive and not breathing normally is considered to be in cardiac arrest.
The next step is activating the emergency medical system by calling 911 or the local emergency number. If a bystander is present, instruct them to make the call and retrieve an AED immediately. This delegation ensures medical help is summoned and the equipment is acquired without delaying chest compressions. If the rescuer is alone, they should call emergency services first before beginning compressions.
Maintaining Circulation Through Continuous CPR
As soon as the emergency call is placed and the AED is en route, high-quality chest compressions must begin. CPR temporarily pumps blood to the brain and vital organs, delaying tissue death until the heart’s electrical rhythm can be restored. Rescuers should aim for a compression rate between 100 and 120 compressions per minute.
Effective compressions require a specific depth of two to 2.4 inches (five to six centimeters) for an adult patient. It is important to allow the chest to recoil fully between compressions, which allows the heart to refill with blood. The rescuer should avoid leaning on the chest during the recoil phase to maximize blood flow.
A primary goal of high-quality CPR is to minimize interruptions, aiming for a chest compression fraction of at least 60 percent of the total resuscitation time. Prolonged pauses decrease the flow of oxygenated blood to the heart and brain, negatively impacting survival. CPR must continue until the AED is present, powered on, and the pads are ready to be attached to the patient.
Preparing the Patient and Applying the Pads
The steps preceding the AED’s analysis involve preparing the patient and applying the electrode pads. The first action upon the AED’s arrival is to power on the device, activating the voice prompts that guide the rescuer. The patient’s chest must be exposed to ensure the pads adhere properly and the electrical current can pass effectively.
The chest area must be prepared by removing clothing, jewelry, or transdermal medication patches that interfere with the current. If the patient’s skin is wet, it must be dried to prevent the electrical current from arcing. Excessive chest hair should be rapidly shaved, often using a razor included in the AED kit, to ensure full pad-to-skin contact.
Selecting the correct pad size is important; pediatric pads deliver a reduced energy dose and should be used for children typically under eight years of age or less than 55 pounds. The electrode pads must be placed firmly on the bare skin in the standard anterolateral position. This placement involves putting one pad on the upper right chest, below the collarbone, and the other on the lower left side, below the armpit. Once the pads are correctly placed and plugged into the AED unit, the rescuer should stop compressions and ensure no one is touching the patient, allowing the device to begin rhythm analysis.