A patient is admitted to the emergency department with chest pain and ECG findings showing ST-segment elevation. The nurse notes oxygen saturation at 89 Which intervention should the nurse prioritize to initiate first?

Administer nitroglycerin immediately to reduce chest pain and lower blood pressure regardless of hemodynamic status.

Administer supplemental oxygen to maintain saturation above 94

Place the patient in supine position to optimize cardiac output and prepare for administration of morphine for pain control.

Start thrombolytic therapy immediately as first-line treatment before obtaining vascular access or ECG monitoring.