An Automated External Defibrillator (AED) is a device used to save lives during sudden cardiac arrest, a condition where the heart’s electrical system malfunctions. The AED delivers a powerful, controlled electrical shock to treat ventricular fibrillation or pulseless ventricular tachycardia. This intervention is time-sensitive, as survival decreases significantly with every minute that passes without defibrillation. Following the proper safety protocol, specifically the instruction to “stand clear,” is paramount for both rescuer safety and treatment success.
Understanding the High-Voltage Electrical Delivery
The AED’s primary function is to eliminate the chaotic electrical activity within the heart muscle that prevents it from pumping blood effectively. To achieve this, the device delivers a significant, high-voltage electrical charge. This energy burst, measured in joules, typically ranges from 120 to 360 joules for adult settings, requiring the internal circuitry to generate thousands of volts.
This powerful shock is not meant to restart a stopped heart, but rather to momentarily depolarize all the heart muscle cells simultaneously. This process effectively stops the erratic electrical signals, allowing the heart’s natural pacemaker to reestablish a normal, organized rhythm. The electricity travels a path from one electrode pad, through the chest cavity and the heart, to the second electrode pad.
Preventing Electrical Conduction to Rescuers
Standing clear is necessary due to the high-voltage electrical energy and the risk of accidental shock to rescuers or bystanders. The human body is a conductor, and if a rescuer is touching the patient, their clothing, or any conductive material, they could become part of the electrical circuit. An accidental shock can cause injuries ranging from painful muscle contractions and skin burns to a disruption of the rescuer’s own heart rhythm. To prevent unintended electrical contact, the verbal command, “Clear!” is announced loudly before the shock button is pressed, ensuring all personnel are safely away from the patient.
Maximizing the Effectiveness of the Treatment
The second reason for standing clear is to ensure the electrical current successfully delivers the full dose of energy to the patient’s heart. If a rescuer is touching the patient, the electrical charge can be diverted or dissipated. This diversion creates an alternate path for the current, reducing the total energy that reaches the heart muscle. A reduced electrical shock is often insufficient to fully depolarize the heart, allowing the chaotic rhythm to continue. Standing clear guarantees the patient receives the full, therapeutic dose of energy required to reset the heart’s electrical system.