A client with acute pericarditis shows restlessness and a dangerous blood pressure change on inspiration. What is the priority action for the nurse?

• A. Begin IV antibiotics
• B. Administer high-flow oxygen
• C. Prepare the client for pericardiocentesis
• D. Initiate anticoagulation therapy

Answer: (C)

Recognizing cardiac tamponade physiology is what makes this situation urgent. In acute pericarditis, fluid can quickly accumulate around the heart, and the signs described—restlessness and a dangerous blood pressure drop with inspiration (pulsus paradoxus)—point to reduced cardiac output from pressure on the heart. The immediate, life-saving step is to relieve that pressure by preparing the client for pericardiocentesis, which drains the excess fluid and restores normal heart filling and circulation. This addresses the root problem of hemodynamic instability rather than just treating symptoms. While oxygen can support tissues and antibiotics or anticoagulation might be appropriate in other contexts, they do not fix the tamponade and could even worsen the situation.