The Automated External Defibrillator (AED) and Cardiopulmonary Resuscitation (CPR) are two interventions that work together to treat sudden cardiac arrest. The AED is designed to analyze the heart’s electrical activity and deliver a controlled electrical shock to correct specific life-threatening rhythms, such as ventricular fibrillation. When the AED begins its analysis, all chest compressions and contact with the patient must stop immediately. This pause is a non-negotiable step to ensure the device can accurately determine the heart’s intrinsic rhythm without interference.
Why Analysis Requires a Complete Pause
The AED’s primary function is to read the patient’s electrocardiogram (ECG) to check for a shockable rhythm, such as ventricular fibrillation or pulseless ventricular tachycardia. Chest compressions create significant physical movement and electrical interference, known as artifact, that corrupts the delicate signal the AED is trying to measure. The device must have a clean, static reading of the heart’s electrical activity to make a correct diagnosis. This electrical noise makes it nearly impossible for the AED’s algorithm to distinguish between a chaotic heart rhythm and movement-induced signal distortion. An inaccurate reading could result in the AED failing to advise a shock when one is needed, or advising a shock when the rhythm is non-shockable. The mandatory pause ensures the diagnostic accuracy of the AED, which directly impacts the success of the rescue attempt.
The Critical Steps During AED Rhythm Analysis
The moment the AED announces it is analyzing the heart rhythm, all rescuers must immediately cease chest compressions and remove their hands from the patient. Minimizing this “hands-off” time is crucial, as any interruption in compressions causes a drop in blood pressure and reduces perfusion to the heart and brain. Rescuers should strive to keep this pause under 10 seconds, which is the recommended maximum interruption limit. A rescuer should loudly announce the verbal command “Clear!” to ensure all individuals step away from the patient. This command confirms that no one is touching the patient, which is a necessary safety precaution and a requirement for the AED to proceed with analysis. The rescuer operating the device should visually confirm that all team members are clear before the AED begins its diagnostic process.
Immediate Actions Following the Analysis
The analysis phase concludes with one of two instructions: “Shock Advised” or “No Shock Advised.” If a shockable rhythm is present, the AED will instruct the rescuer to stand clear and begin charging. The rescuer must issue the “Clear!” command again, ensure no one is touching the patient, and then press the shock button on semi-automatic models.
Following either a successful shock delivery or the “No Shock Advised” instruction, the next action is to immediately resume high-quality chest compressions. There should be no delay in returning to compressions, as circulation must be restored manually. The goal is to restart compressions within five seconds of the AED’s message. The rescuer should continue with a full two-minute cycle of CPR before the AED prompts for another rhythm analysis. If no shock is advised, CPR is the only available intervention to keep oxygenated blood moving.