The command “clear” is routinely heard during medical emergencies involving a defibrillator. This device delivers a controlled electrical shock to the heart to address life-threatening rhythms. The phrase “clear” serves as a safety command.
The Purpose of the “Clear” Command
The command “clear” ensures the safety of everyone near the patient and defibrillator during a shock. It signals that no one should be in physical contact with the patient, the bed, or any connected equipment when the electrical discharge occurs. This measure is essential due to the significant voltage and current delivered by the device; accidental electrocution can cause severe injury or be fatal.
If a person is in contact with the patient, the electrical current could pass through them. Defibrillators can deliver energy ranging from 150 to 360 joules for adults, with internal voltages between 1,000 and 2,000 volts. Even a small amount of this energy can be dangerous, potentially causing injury or an abnormal heart rhythm. Automated external defibrillators (AEDs) also issue voice prompts like “stand clear of the patient” to emphasize this safety.
How Defibrillators Deliver a Therapeutic Shock
Defibrillators deliver a controlled electrical shock to the heart. The purpose of this shock is to interrupt abnormal, chaotic electrical activity, such as ventricular fibrillation or pulseless ventricular tachycardia. In these conditions, the heart’s lower chambers quiver ineffectively instead of pumping blood, leading to sudden cardiac arrest.
The electrical discharge from a defibrillator momentarily depolarizes a significant portion of the heart muscle. This widespread depolarization aims to halt the chaotic electrical signals, allowing the heart’s natural pacemaker, the sinoatrial node, to regain control and re-establish a normal, coordinated rhythm. The powerful nature of this electrical current, which passes through the body, underscores why the “clear” command is a necessary safety protocol.
The Coordinated Defibrillation Procedure
The use of a defibrillator involves a series of coordinated actions, with the “clear” command being a central safety protocol. Once a shockable rhythm is identified and the defibrillator pads are correctly applied to the patient’s bare chest, the device is charged. Before the shock is delivered, the medical team or rescuer verbally announces “clear” loudly and often visually confirms that everyone has moved away from the patient and any connected surfaces. This ensures no one is inadvertently in contact with the patient during the high-energy discharge.
Following the “clear” command and confirmation, the shock button is pressed to deliver the electrical energy. Automated external defibrillators (AEDs) guide users through these steps with voice prompts. After the shock, cardiopulmonary resuscitation (CPR) is immediately resumed, and the defibrillator may re-analyze the heart rhythm, potentially requiring another “clear” command for subsequent shocks. This sequence highlights that “clear” is an integral part of a larger, highly structured, and safety-focused medical procedure that relies on precise communication and teamwork.