A patient recovering from cardiac surgery is showing signs of decreased cardiac output and related complications. Which nursing intervention should the nurse prioritize to ensure patient safety and promote recovery?

Decreased cardiac output is a state where the heart fails to pump sufficient blood to meet metabolic demands, leading to tissue hypoperfusion, hypotension, tachycardia, altered mental status, and organ dysfunction. Post–cardiac surgery patients are at high risk due to myocardial stunning, fluid shifts, and potential dysrhythmias. Rationale: A. Administering high-dose diuretics without assessment may worsen hypotension and reduce preload excessively. In post-cardiac surgery patients, fluid balance is delicate. This does not first address hemodynamic instability or confirm volume status. B. Early ambulation is beneficial in recovery but is unsafe in a patient with suspected decreased cardiac output. It may increase myocardial oxygen demand. This intervention does not prioritize stabilization of perfusion status. C. Close monitoring of vital signs and assessment for signs of poor perfusion is the priority action. It allows early detection of hypotension, oliguria, altered mentation, and cool extremities. This directly supports identification of hemodynamic compromise and guides immediate intervention. D. Oxygen therapy may be necessary but should not be administered without full assessment. Oxygen alone does not correct low cardiac output. This does not address the underlying issue of systemic hypoperfusion or guide definitive management.