When a person experiences sudden cardiac arrest, their heart abruptly stops beating effectively, preventing blood flow to the brain and other organs. This immediate medical emergency requires swift action to improve the chances of survival. Automated External Defibrillators (AEDs) are devices designed to deliver an electrical shock to the heart, which can help restore a normal rhythm. Understanding the correct sequence of actions, especially after an AED delivers a shock, is important for effective resuscitation.
The Critical Next Step: Immediate CPR Resumption
After an AED delivers an electrical shock, immediately resume cardiopulmonary resuscitation (CPR). Resume without delay, starting with chest compressions, and without checking for a pulse or waiting for further AED prompts. The purpose of the electrical shock is to stop the chaotic electrical activity in the heart, such as ventricular fibrillation, allowing its natural pacemaker to potentially reset to a normal rhythm. However, the shock itself does not guarantee immediate return of effective blood circulation.
Continuing chest compressions after a shock maintains blood flow to the brain and other vital organs, which may have been oxygen-deprived during cardiac arrest. Studies indicate that even after a successful defibrillation, the heart may remain pulseless for a period, making ongoing compressions necessary to perfuse the heart muscle itself. Minimizing “hands-off” time—the period when chest compressions are paused—is important for improving outcomes. Keep these interruptions brief, ideally under 10 seconds, to ensure continuous blood flow.
Navigating the AED Process
Using an AED involves a clear sequence of steps. Turn on the AED immediately and follow its voice prompts. The next step involves attaching electrode pads to the person’s bare chest, typically one on the upper right side and the other on the lower left side, following the diagrams on the pads. It is important to ensure the chest is dry for proper pad adhesion.
After pad placement, the AED analyzes the heart’s rhythm. Do not touch the person during analysis to avoid interference. If a shockable rhythm is detected, the AED will advise “stand clear” and instruct the rescuer to deliver the shock (or deliver it automatically). Conversely, if the AED advises “no shock advised,” it means the device has detected a non-shockable rhythm, such as asystole or pulseless electrical activity, or that a normal rhythm has returned. In such cases, CPR should continue without interruption, as the heart still needs mechanical support to circulate blood.
Optimizing Resuscitation Efforts
Effective CPR has several components to maximize positive outcomes. Chest compressions should be delivered at a rate of 100 to 120 compressions per minute. The depth of compressions for an adult should be at least 2 inches (5 cm) but no more than 2.4 inches (6 cm). Allowing for full chest recoil after each compression is also important, as this enables the heart to fully refill with blood before the next compression.
Minimizing interruptions in chest compressions maintains continuous blood flow to the heart and brain. When two or more rescuers are present, they should switch compression roles approximately every two minutes to prevent fatigue and maintain high-quality compressions. Consistent, high-quality CPR, combined with timely defibrillation, improves survival rates in sudden cardiac arrest.