Which intervention should a nurse prioritize for a patient with a risk of venous thromboembolism (VTE) in the postoperative phase?

Venous thromboembolism results from venous stasis, endothelial injury, and hypercoagulability (Virchow’s triad), which are common in postoperative patients due to immobility, surgical trauma, and inflammatory activation of coagulation pathways, increasing risk of deep vein thrombosis and pulmonary embolism. Rationale: A. Early ambulation and leg exercises promote venous return by activating the calf muscle pump, reducing venous stasis, and improving endothelial circulation. This is the most effective and evidence-based nursing intervention to prevent postoperative VTE. B. High-dose anticoagulants preoperatively are not routinely administered due to increased risk of perioperative bleeding and hemorrhagic complications. Anticoagulation is carefully timed and individualized, not universally used before surgery. C. Warm compresses may provide local vasodilation, but they do not significantly reduce thrombus formation risk in immobilized postoperative patients. They are not a primary preventive strategy for VTE. D. Limiting fluid intake increases blood viscosity and may worsen venous stasis, thereby increasing VTE risk. Adequate hydration is important to maintain circulatory volume and reduce clot formation risk.