A client with heart failure (HF) develops cardiac tamponade. The client has muffled, distant heart sounds, and is anxious and restless. After initiating oxygen therapy and IV hydration, which intervention is most important for the nurse to implement?

A. Monitor oxygen saturation via continuous pulse oximetry: While oxygen monitoring is important in any cardiac emergency, it does not address the underlying life-threatening cause. Tamponade requires urgent mechanical relief, not just oxygenation support. B. Notify healthcare provider to prepare for pericardiocentesis: Cardiac tamponade is a medical emergency that restricts cardiac filling and output. Pericardiocentesis, which involves removing fluid from the pericardial sac, is the definitive and most urgent intervention to relieve pressure and prevent cardiovascular collapse. C. Assess for paradoxical blood pressure: Measuring for pulsus paradoxus can help confirm tamponade but takes time and does not treat the condition. It should not delay notifying the provider for immediate intervention. D. Observe neck for jugular vein distention: JVD is a common sign of tamponade but observing for it at this stage provides little new information. The presence of muffled heart sounds and restlessness already indicate that emergent treatment is necessary.