The Automated External Defibrillator (AED) delivers an electrical shock to a person in sudden cardiac arrest, typically when the heart is in an abnormal rhythm like ventricular fibrillation. The electric current temporarily stops the erratic electrical activity, allowing the heart’s natural pacemaker to restart with a normal rhythm. The command to “clear” the victim is the most important safety action, protecting the rescuer and bystanders from accidental electrocution. Understanding the precise timing of this command ensures the safe and effective delivery of the shock. This article details the procedural moments when the rescuer must clear the victim before, during, and immediately after the shock delivery.
Initial Setup and Preparation
The process begins with the swift preparation of the victim and the device before the AED analyzes the heart’s electrical activity. After turning on the AED, the rescuer must quickly expose the victim’s chest, ensuring the skin is bare for pad placement. If the chest is wet, it must be wiped dry, as water conducts electricity and could compromise the shock’s effectiveness or create a safety hazard.
The self-adhesive electrode pads are applied directly to the skin in specific locations. One pad goes on the upper right side of the chest, just below the collarbone, and the other on the lower left side, below the armpit. Once the pads are affixed and the connector cable is plugged into the AED, the initial setup is complete. During this preparation phase, there is no electrical risk, so the rescuer should not issue a “clear” command. Continuous chest compressions (CPR) should ideally continue until the AED is ready to analyze the rhythm.
The Analysis Phase and Shock Determination
After the pads are connected, the AED announces that it is analyzing the heart rhythm. This is the first moment the rescuer must ensure no one touches the victim. Movement can create electrical interference that prevents the AED from accurately reading the heart’s rhythm. The device typically prompts, “Analyzing heart rhythm, do not touch the patient,” and the rescuer should verbally confirm this instruction to bystanders.
If the AED detects a shockable rhythm, such as ventricular fibrillation, it immediately begins charging its internal capacitor. The transition from analysis to charging marks the definitive point for the “clear” command, as the device is preparing to deliver an electrical pulse. The AED issues a loud verbal warning, such as “Shock advised, charging, stand clear.” This automated instruction cues the rescuer to take immediate action to ensure safety before the shock is delivered.
Executing the Safety Clearance
The moment the AED announces a shock is advised and begins charging, the rescuer must execute a loud, multi-step clearance procedure. The first step involves a commanding verbal announcement to warn all personnel and bystanders clearly and unequivocally. A commonly taught phrase is, “I’m clear, you’re clear, everybody clear!” This ensures that the rescuer themselves, any assisting rescuers, and any accidental bystanders are all alerted. This verbalization is necessary because the environment may be loud or chaotic.
The second, non-negotiable step is a visual scan of the victim and the immediate area. The rescuer must quickly confirm that no one is in physical contact with the victim, the victim’s clothing, or anything else touching the patient that could conduct electricity. This visual check is particularly important for ensuring that a secondary rescuer has not inadvertently kept a hand on the victim’s chest or limbs.
Finally, once the verbal and visual confirmation of clearance is complete and the AED has fully charged, the rescuer presses the shock button, if the device requires manual delivery. Some modern AEDs are fully automatic and will deliver the shock without a button press. However, the clearance procedure remains mandatory for safety regardless of the device type. The shock delivery will cause the victim’s body to contract suddenly, which is a normal physiological response.
Immediate Post-Shock Resuscitation
Once the AED successfully delivers the electrical shock, the rescuer must transition instantly to the next phase of resuscitation. The AED will often verbally prompt the rescuer with a phrase like, “Shock delivered, begin CPR now,” and the rescuer should immediately resume chest compressions. It is a common misconception that the rescuer should pause to check for a pulse or a change in the victim’s condition.
Current resuscitation guidelines emphasize minimizing interruptions to chest compressions, as effective CPR is necessary to circulate oxygenated blood to the heart and brain. Therefore, the rescuer should not check for a pulse or wait for the AED to provide further instructions before restarting CPR. The AED pads should remain attached, and the device will continue to monitor the patient’s heart rhythm for the next two minutes of continuous CPR. After this two-minute cycle, the AED will prompt a re-analysis, and the entire cycle—including a new “clear” command if a subsequent shock is advised—will begin again.