Which of the following medications is used in CPR to prevent tachyarrhythmias?

Lidocaine is the correct choice as it is an antiarrhythmic medication commonly used in cardiac resuscitation to manage ventricular tachycardia and prevent tachyarrhythmias during advanced cardiac life support (ACLS). When a patient experiences a cardiac arrest, particularly with a rhythm that can lead to ventricular fibrillation, lidocaine helps stabilize the cardiac membrane and can decrease the risk of further arrhythmias.

This medication works by blocking sodium channels and reducing the excitability of cardiac tissue, thus helping to restore normal heart rhythm. It can be administered intravenously during a resuscitation scenario if the patient displays these types of rapid or chaotic heart rhythms.

Other medications listed serve different purposes. For instance, adenosine is primarily used for the rapid conversion of certain supraventricular tachycardias, but it is not typically employed as part of the CPR protocol for preventing tachyarrhythmias. Furosemide is a loop diuretic and has no direct role in managing arrhythmias, as its primary function is fluid management. Atropine is used to treat bradycardia rather than tachyarrhythmias, making it ineffective for the purpose of preventing rapid heart rhythms during CPR.