Final answer:
In the case of ventricular fibrillation observed on a cardiac monitor, the nurse's first priority is to perform defibrillation, usually with an automated external defibrillator (AED), to attempt to restore a normal sinus rhythm and prevent brain death.
Step-by-step explanation:
The nurse's first priority intervention when observing ventricular fibrillation (V-FIB) on a cardiac monitor is to initiate defibrillation. Ventricular fibrillation is a life-threatening condition where the heart beats in an erratic, uncontrolled manner, preventing it from pumping blood effectively. It's often described as "code blue" in a hospital setting. In this emergency, the application of an electrical shock via a defibrillator can save the patient's life by stopping the heart momentarily and allowing the sinoatrial (SA) node to reestablish a normal sinus rhythm. Automated external defibrillators (AEDs) are devices that can be used even by nonmedical personnel, providing verbal instructions and automating the diagnosis and delivery of the shock with appropriate energy and waveform. Immediate defibrillation is critical because, if untreated, ventricular fibrillation can lead to brain death within minutes.