When someone suddenly collapses, becoming unresponsive and not breathing normally, they may be experiencing Sudden Cardiac Arrest (SCA). This medical emergency occurs when the heart’s electrical system malfunctions, causing it to quiver ineffectively instead of pumping blood. Survival requires the combined use of Cardiopulmonary Resuscitation (CPR) and an Automated External Defibrillator (AED). CPR manually circulates blood and oxygen to the brain and vital organs, while the AED delivers an electric shock to reset the heart’s electrical rhythm.
The Immediate Priority: Why Start CPR First
When sudden cardiac arrest is recognized, the priority is to begin chest compressions immediately. While the AED is the definitive treatment to correct the electrical problem, CPR maintains life until the device is ready. Every minute that passes without intervention decreases the chance of survival significantly, sometimes by as much as 7 to 10 percent per minute.
Prioritizing compressions is necessary because the brain and heart muscle require a continuous supply of oxygenated blood. Chest compressions, delivered hard and fast at a rate of 100 to 120 per minute, create artificial blood flow. This manual pumping action keeps the core organs perfused, stabilizing them and increasing the likelihood that the heart will respond to a later electrical shock.
Before rushing to an AED, one person should call emergency services (like 911). If others are present, immediately assign someone to retrieve the AED. CPR should not be delayed while waiting for the machine to arrive. The goal is to establish high-quality chest compressions with minimal interruptions while the AED is being prepared.
Integrating the AED: Steps for Use
Once the AED arrives, applying the pads should be integrated seamlessly with ongoing compressions. The person performing CPR should continue compressions while a second rescuer prepares the AED by turning it on and exposing the person’s chest. The chest must be bare and dry to ensure proper pad adhesion and electrical conduction, which may require quickly drying the skin or removing excessive body hair.
For adults, the standard placement is the anterior-lateral position. One pad is placed on the upper right side of the chest, just below the collarbone. The other pad is placed on the lower left side of the chest, along the rib cage below the left nipple. This positioning ensures the electrical current passes through the heart to maximize shock effectiveness.
After the pads are securely attached, the connector cable is plugged into the AED unit. The AED will issue voice prompts, guiding the rescuer to stand clear while it analyzes the heart rhythm. If a shockable rhythm, such as ventricular fibrillation, is detected, the AED will advise a shock and begin charging. If no shock is advised, the rescuer must immediately resume CPR.
Seamless Transition: Coordinating CPR and AED Shocks
The moment the AED advises a shock, the rescuer must ensure no one is touching the person, loudly announcing, “Clear!” before pressing the shock button. Following the shock delivery, or if the AED determines no shock is needed, CPR must be immediately resumed, beginning with chest compressions. This immediate return to compressions is essential to maintain circulation.
Current guidelines emphasize minimizing “hands-off” time—the period when chest compressions are stopped. Pauses should be kept as brief as possible, ideally under 10 seconds, to prevent a drop in blood pressure. The AED is programmed to re-analyze the heart rhythm approximately every two minutes. Rescuers should continue the cycle of CPR until the next analysis or until professional help arrives.
Coordinating actions is important if multiple rescuers are present. One person can focus solely on delivering high-quality compressions while the other manages the AED and prepares for rhythm analysis and potential shock. The goal is to ensure constant blood flow, interrupting compressions only for rhythm analysis and defibrillation therapy.