When a person suffers sudden cardiac arrest, the two most important interventions are immediate, high-quality chest compressions and rapid application of an Automated External Defibrillator (AED). Cardiopulmonary Resuscitation (CPR) manually circulates blood and oxygen to the brain and heart until defibrillation can occur, which is the only treatment that can correct the electrical problem. Modern guidelines emphasize that success hinges on minimizing the time the patient’s chest is not being compressed, known as “hands-off time.” The core objective is to seamlessly integrate the AED into the CPR sequence to maintain continuous blood flow.
Why Compression Interruptions Are Detrimental
Every chest compression acts as a pump, creating pressure that drives oxygenated blood toward the brain and heart. Interrupting compressions, even briefly, causes an immediate and significant fall in this pressure. When compressions stop, the coronary perfusion pressure (CPP)—the pressure gradient that perfuses the heart muscle—drops instantly to zero within seconds.
This loss of pressure means the heart is not receiving the blood flow needed to sustain life or respond effectively to a defibrillation shock. It takes several subsequent compressions to re-establish an adequate level of CPP after a pause. Short interruptions, lasting just five to ten seconds, can dramatically reduce the overall chance of survival.
Practical Steps for Rapid AED Integration
The process of applying and using the AED must be performed while compressions are actively being delivered to achieve the minimum hands-off time. Ideally, if multiple rescuers are present, roles should be assigned immediately, with one person continuing chest compressions without pause. The second rescuer should retrieve the AED, turn it on, and begin preparing the patient’s chest for pad placement.
Preparation involves exposing the chest and ensuring the skin is dry, which can be done while the first rescuer continues compressions. The electrode pads are then opened and readied for application, following the diagrams for correct placement—typically one pad on the upper right side of the chest and the other on the lower left side. The goal is to set up the entire AED system around the rescuer who is actively performing CPR.
The only moment compressions must stop is for the briefest possible period required to attach the pads and allow the AED to analyze the heart rhythm. This time, often referred to as the “perishock pause,” is the target for reduction, ideally lasting less than ten seconds. As soon as the pads are securely placed and the cable is plugged into the AED unit, the rescuer must immediately move away and announce “clear” to allow the device to analyze the electrical activity.
If the AED advises a shock, the device will prompt the rescuer to push a button or will deliver the shock automatically after charging. Some professional-grade AEDs can be pre-charged during the last few seconds of a two-minute compression cycle to further reduce the pause. The shock must be delivered immediately once the patient is clear and the machine is ready.
The moment the shock is delivered, or if the AED advises “no shock advised,” the rescuer must immediately place their hands back on the chest and resume compressions. There should be no delay to check for a pulse or breathing at this point, as compressions remain the priority. This sequence of rapid analysis, shock, and immediate resumption is the most effective method for minimizing the hands-off time associated with defibrillation.
Maintaining High-Quality Compression Standards
Minimizing interruptions is only half of the equation; the compressions delivered must be effective to generate life-sustaining blood flow. High-quality CPR requires maintaining a consistent compression rate of 100 to 120 compressions per minute.
The depth of each compression is equally important, requiring the adult chest to be depressed at least two inches (five centimeters), but not exceeding 2.4 inches (six centimeters). This depth is necessary to adequately compress the heart between the breastbone and the spine.
Rescuers must also ensure they allow for full chest recoil between compressions. Full recoil allows the chest wall to return to its normal position, creating a vacuum that lets the heart refill with blood. Avoiding leaning on the chest prevents this refill. The ultimate goal is to achieve a Chest Compression Fraction (CCF) of greater than 80%.