A client who is on the progressive care unit develops supraventricular tachycardia (SVT). The client vital signs: T 98, HR 160, BP 119/71, RR 19, SpO2 94% on RA. The client presents with no dyspnea, shortness of breath and chest pain. Which action that is included in the hospital dysrhythmia protocol should the nurse do first?

A. Perform immediate defibrillation: Defibrillation is indicated for life-threatening, pulseless ventricular tachycardia or ventricular fibrillation. The client is hemodynamically stable with a pulse, normal blood pressure, and no signs of shock, so immediate defibrillation is not appropriate and could be harmful. B. Administer adenosine 6 mg IVP: For stable supraventricular tachycardia (SVT), the first-line pharmacologic intervention is rapid IV push of adenosine, starting with 6 mg. Adenosine temporarily blocks AV nodal conduction, often terminating the SVT, and is preferred in stable clients before electrical cardioversion. This aligns with ACLS protocols. C. Perform immediate cardioversion: Synchronized cardioversion is reserved for unstable SVT patients exhibiting hypotension, chest pain, altered mental status, or signs of shock. The client is currently stable, so cardioversion is not the first action but would be considered if adenosine fails or the client becomes unstable. D. Administer adenosine 12 mg IVP: The 12 mg dose is used only as a second dose if the initial 6 mg fails to convert the rhythm. Administering 12 mg first bypasses the recommended stepwise approach and may increase the risk of adverse effects such as transient bradycardia or AV block.