An Automated External Defibrillator (AED) is a portable device used to treat Sudden Cardiac Arrest (SCA) by delivering an electrical shock. This shock interrupts chaotic heart rhythms, such as ventricular fibrillation, allowing the heart’s natural pacemaker to resume a normal beat. The AED process is guided by voice prompts and involves steps designed for efficacy and safety. The command to “clear” the victim is the most important safety protocol, ensuring the high-energy electrical discharge is delivered safely and effectively.
Protecting Rescuers and Bystanders from Electrical Current
The primary danger of not clearing the victim is the risk of accidental electrocution to the rescuer and bystanders. An AED delivers a powerful electrical current, which is enough to reset the heart’s electrical system. Electricity follows the path of least resistance, and anyone touching the victim when the shock is delivered can become part of the electrical circuit.
Contact with the victim’s skin, clothing, or conductive materials like a metal stretcher or wet floor allows the current to pass through the rescuer’s body. This unintended shock can range from a mild tingling sensation to a dangerous shock, potentially disturbing the rescuer’s own heart rhythm.
Moisture presents a high risk because water is an excellent conductor of electricity. If the victim is lying in a puddle, the electrical energy can be diverted away from the heart and shock anyone in contact with the water or the victim. The “clear” command forces everyone to break this conductive chain. Rescuers must visually confirm that no one is in contact with the victim before pressing the shock button, ensuring the current’s only path is directly between the two AED pads across the victim’s chest.
Mitigating Physical Injury During the Shock
The high-energy shock causes a sudden, intense, involuntary muscle contraction in the victim’s body, often described as a violent jolt. The “clear” command ensures no one is physically restraining the victim or in a position to be struck by the victim’s limbs during this movement.
If a rescuer is leaning over the victim or touching them when the shock is administered, the sudden movement could cause the rescuer to be thrown back or suffer injury. The victim is also at risk of secondary injury, such as hitting their head on the ground. Clearing the victim ensures a safe perimeter around the patient, allowing all individuals to step back and protect themselves from the kinetic energy transferred to the victim’s body.
Why the Clear Command Ensures Effective Treatment
The “clear” command is procedurally important for the AED’s function and treatment efficacy. The AED must accurately analyze the heart’s electrical activity to determine if a shockable rhythm is present. If anyone touches the patient during the analysis phase, the AED may pick up interference from the rescuer’s electrical activity or movement, leading to a misreading of the heart rhythm.
When a shock is advised, the command acts as a final checkpoint to confirm the environment is clear and the pads are properly secured. Poor contact between the pads and the skin increases transthoracic impedance, which is the electrical resistance of the body. High impedance reduces the current reaching the heart, lowering the chance of successful defibrillation.
The clear command mandates a visual sweep, ensuring the pads are firmly seated and the victim’s chest is dry. Adherence to this protocol ensures the delivery of the full, therapeutic dose of electricity to the heart muscle. Following the AED’s prompts provides the best chance of restoring a normal heart rhythm.