A client was admitted to the cardiac observation unit 2 hours ago reporting chest pain. On admission, the client's electrocardiogram (ECG) displays sinus bradycardia (SB) with ST segment depression, but no ventricular ectopy. The client suddenly reports a sharp increase in pain, telling the nurse, "I feel like an elephant just stepped on my chest." The ECG now displays Q waves and ST segment elevations in the anterior leads. Which interventions should the nurse perform?

A. Obtain a stat 12-lead ECG and perform a venipuncture to check cardiac enzyme levels: The client's symptoms and ECG changes now indicate an evolving acute myocardial infarction (AMI), especially with new Q waves and ST elevation. Immediate confirmation with another ECG and troponin/CK-MB levels is critical for rapid diagnosis and treatment. B. Notify the healthcare provider of the client's increased chest pain and call for the defibrillator crash cart: While it's essential to notify the provider, calling for a crash cart is premature unless the client is unstable or experiences life-threatening arrhythmias. C. Increase the peripheral IV flow rate to 175 mL/hr to prevent hypotension and shock: Rapid IV fluid administration can worsen cardiac workload and lead to pulmonary congestion in clients with evolving MI, particularly if left ventricular function is compromised. D. Administer prescribed morphine sulfate IV and provide oxygen at 2 L/minute per nasal cannula: Morphine and oxygen are standard interventions for MI, but they should follow diagnostic confirmation. Overuse of oxygen in non-hypoxic patients may cause harm, and morphine may mask symptoms needed for evaluation.