Defibrillators are devices that enable the patient to be saved by returning the heart to normal sinus rhythm in cases of vital cardiac anomalies such as asystole or fibrillation, and they do this by passing a short-term but high-capacity current through the patient.
Defibrillators are devices that can increase the energy they receive from their batteries via booster circuits to up to 360 J within seconds. Defibrillators are divided into two categories based on electrical conduction: monophasic and biphasic. Monophasic defibrillators deliver current in the positive phase, meaning it's unidirectional, while biphasic defibrillators deliver current in both the positive and negative phases, meaning it's bidirectional. A crucial factor here is ensuring that the delivered current is delivered asynchronously with the T wave to prevent ventricular fibrillation. Most defibrillators today use an ECG-based algorithm called Cardioversion to achieve this.
Another type of defibrillator that is becoming increasingly common is the AED (Automated External Defibrillator). AEDs are automated defibrillators primarily found in public spaces, such as factories, schools, museums, universities, offices, public buildings, and other areas with high human populations and traffic. AEDs are designed to operate when needed, minimizing user involvement.
Once activated, an AED uses audio and visual prompts to guide the user through the pads, enabling resolution of the situation. It delivers a preset current to the patient, defined for pediatric and adult patients, via the pads. AEDs first determine whether the patient requires this current through rapid ECG analysis and then deliver the shock. In this way, semi-autonomous AEDs are one of the barriers between us and potential death or permanent brain damage.
