Impact of Training Nurses Through Realistic Simulation for Performing Cardiopulmonary Resuscitation With Emphasis on Electrical Therapy: Randomized Clinical Trial

Cardiopulmonary arrest (CPA) represents one of the most prevalent cardiovascular emergencies worldwide and is associated with high morbidity and mortality. In Brazil, approximately 14 million individuals have some form of cardiovascular disease (CVD), accounting for nearly 400,000 deaths annually, which corresponds to about 30% of all deaths recorded in the country.

According to the Brazilian Society of Cardiology, CVDs were responsible for more than 198,000 deaths in 2020 and constitute the primary underlying causes of CPA. Early recognition of CPA is therefore critical, as it is directly associated with improved outcomes and better patient prognosis.

CPA may present with four cardiac rhythms: asystole, pulseless electrical activity (PEA), ventricular fibrillation (VF), and pulseless ventricular tachycardia (pVT). Among these, only VF and pVT are shockable rhythms. In adult patients with sudden cardiac arrest due to VF or pVT, the heart exhibits disorganized electrical activity that is ineffective in maintaining perfusion to vital organs. In such cases, survival rates are significantly higher when immediate chest compressions and early defibrillation are performed.

Defibrillation is defined as the delivery of a controlled electrical shock aimed at terminating an abnormal cardiac rhythm, particularly life-threatening arrhythmias. During defibrillation, an electrical current induces simultaneous depolarization of myocardial cells. Although this intervention does not directly restore effective cardiac output, it creates the conditions necessary for the resumption of organized electrical activity. If myocardial viability is preserved, pacemaker cells may regain control of cardiac rhythm, resulting in the return of spontaneous circulation (ROSC).

The energy dose delivered during defibrillation depends on the type of defibrillator used. Biphasic defibrillators, currently the most widely used devices, typically deliver initial shocks ranging from 120 to 200 joules, with the possibility of escalation according to manufacturer recommendations. In contrast, monophasic defibrillators generally require a fixed dose of 360 joules. A monophasic waveform delivers current in a single direction, whereas a biphasic waveform alternates the direction of current flow, a phenomenon known as polarity reversal, which improves defibrillation efficiency.