An Automated External Defibrillator, commonly known as an AED, is a portable medical device designed to treat sudden cardiac arrest. This medical emergency occurs when the heart stops beating effectively, often due to an electrical malfunction. The AED’s primary function is to deliver an electrical shock to the heart, aiming to restore a normal, effective rhythm. The “analyzing” phase is an important step in this process.
What Happens During Analysis
During the analysis phase, the AED performs a diagnostic assessment of the patient’s heart rhythm. Once the electrode pads are applied to the patient’s chest, the AED connects to the heart’s electrical activity through these pads. It then processes electrical signals, interpreting waveform patterns to identify arrhythmias.
The AED primarily looks for two types of shockable rhythms: ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT). In ventricular fibrillation, the heart’s electrical activity is chaotic and uncoordinated, leading to ineffective pumping. Pulseless ventricular tachycardia involves a rapid, but organized, electrical rhythm that prevents the heart from pumping blood effectively. The device’s algorithms distinguish these rhythms from non-shockable rhythms or normal heart activity.
Your Role During Analysis
When the AED announces it is “analyzing” the heart rhythm, it is necessary for everyone to stand clear of the patient. This instruction is important for two main reasons: ensuring the accuracy of the AED’s rhythm analysis and preventing accidental electrical shock to anyone touching the patient. Any movement or contact with the patient during this diagnostic period can introduce electrical interference, potentially distorting the heart’s electrical signals. Such interference could lead to an inaccurate assessment by the device, causing it to either advise a shock when none is needed or, dangerously, fail to advise a shock when one is required. Rescuers must verbally announce “clear” and visually confirm no one is touching the patient, the bed, or any connected equipment before analysis.
What Comes Next
After the AED completes its analysis, it will deliver one of two prompts, guiding the rescuer on the subsequent actions. If the AED detects a shockable rhythm, such as ventricular fibrillation or pulseless ventricular tachycardia, it will announce “shock advised” and begin charging. Once charged, the device will prompt the rescuer to press the shock button, again requiring a clear environment around the patient to ensure safety.
Alternatively, if the AED determines that the patient’s rhythm is not shockable—either because it is a normal rhythm, an organized but slow rhythm, or a flat line (asystole)—it will announce “no shock advised.” In this scenario, delivering an electrical shock would not be beneficial and could potentially harm the patient. The AED will then instruct the rescuer to continue cardiopulmonary resuscitation (CPR), focusing on uninterrupted chest compressions and rescue breaths, until advanced medical help arrives or the patient shows signs of recovery.