What is the appropriate next step in caring for a patient showing signs of tachycardia and adequate perfusion?

When a patient presents with signs of tachycardia but maintains adequate perfusion, performing a 12-Lead ECG is crucial. This step allows for the detailed assessment of the heart's electrical activity, which is vital for identifying the specific type of tachycardia. Understanding whether the tachycardia is atrial, ventricular, or of another origin can significantly impact the subsequent management of the patient.

The findings from the ECG can help determine if the tachycardia is caused by conditions such as atrial fibrillation, supraventricular tachycardia, or a more serious concern such as ventricular tachycardia. Each of these conditions has different implications for treatment and potential complications.

Additionally, while supplemental oxygen and intravenous fluids are generally supportive measures, they do not address the underlying cause of the tachycardia. Administering fluids may be appropriate in certain situations where the patient's perfusion status becomes compromised; however, the immediate focus should be on diagnosing the rhythm through the ECG. Initiating defibrillation is reserved for life-threatening arrhythmias or when the patient exhibits no pulse, which is not the case here as the patient is currently well-perfused.

Therefore, conducting a 12-