After initiating nitroglycerin infusion for acute coronary syndrome, which finding should be addressed first?

When managing a patient who has just started a nitroglycerin infusion, the priority is to address symptoms that indicate potential hemodynamic instability. The feeling of dizziness and lightheadedness can suggest that the patient is experiencing hypotension or a significant drop in blood pressure due to the vasodilatory effects of nitroglycerin. This is critical, as hypotension can compromise organ perfusion and lead to more serious complications.

In contrast, while a headache is a common side effect of nitroglycerin therapy and should be monitored, it is usually not as immediately threatening as a drop in blood pressure. Feeling flushed is another common reaction that generally does not require urgent intervention. Reporting feelings of nervousness, while it may be distressing for the patient, does not typically indicate an acute change in their physiological status.

Thus, the most pressing concern in this situation is the patient's dizziness and lightheadedness, which warrants prompt evaluation and possibly intervention to ensure the safety and stability of the patient.