Final answer:
The nurse's first response to these assessment findings would be to administer oxygen and immediately report the findings to the healthcare provider.
Step-by-step explanation:
The nurse's first response to these assessment findings would be to b. Administer oxygen and immediately report the findings to the healthcare provider. These findings indicate potential complications of acute pericarditis, such as cardiac tamponade. Administering oxygen can help improve oxygenation, while reporting the findings to the healthcare provider allows for further evaluation and appropriate interventions.