Final answer:
The priority nursing intervention for a patient with a STEMI receiving alteplase is to monitor for signs of bleeding, as the thrombolytic therapy increases the risk of hemorrhage.
Step-by-step explanation:
The priority nursing intervention for a patient receiving a tissue plasminogen activator, alteplase, who has been diagnosed with a ST-segment elevation MI (STEMI) would be to monitor for signs of bleeding. Tissue plasminogen activator is a key thrombolytic agent used in the treatment of MI that works by catalyzing the conversion of plasminogen to plasmin, which in turn breaks down clots. As such therapy increases the risk of bleeding, nurses must vigilantly check for signs of hemorrhage, which can occur at various sites including the gastrointestinal tract, urinary tract, or even cerebrally. Additionally, routine procedures such as having alternative medications like heparin sodium available are also essential as they may be required for continued management of the patient's condition.