A nurse is caring for a client 2 days after total knee replacement surgery. Which nursing intervention is the priority to prevent the most serious postoperative complication?

Pulmonary embolism is the most serious complication after total knee replacement, making assessment for signs like dyspnea and chest pain the priority. Other interventions address important but less life-threatening issues.

Understanding the Priority: Airway, Breathing, Circulation
When prioritizing care for a postoperative client, the nursing framework of Airway, Breathing, and Circulation (ABCs) is essential. While all the listed interventions are important, the nurse must first address the complication that poses the most immediate threat to life. For a client two days after a total knee replacement (TKA), the most serious and rapidly fatal postoperative complication is a pulmonary embolism (PE).

Why Pulmonary Embolism is the Priority
A pulmonary embolism is a direct threat to breathing and circulation. It occurs when a blood clot, most commonly a deep vein thrombosis (DVT) from the lower extremity, travels to the lungs and obstructs a pulmonary artery. This blockage causes a sudden and severe ventilation-perfusion mismatch, leading to rapid hypoxemia, and can precipitate right-sided heart failure and cardiovascular collapse.

The risk of developing a venous thromboembolism (VTE), which includes both DVT and PE, is significantly elevated after major joint surgery. Research confirms that patients undergoing total joint arthroplasty, including TKA, are at an increased risk for this specific postoperative complication ^[1]. The clinical burden of VTE is substantial, making its prevention and early detection a cornerstone of postoperative care ^[1]. Without prompt recognition and intervention, a massive PE can be fatal within minutes to hours. Therefore, actively assessing for its signs and symptoms, such as sudden dyspnea, pleuritic chest pain, tachycardia, and apprehension, is the most critical nursing action to prevent death.

Analyzing the Other Interventions
The other options are standard and necessary components of postoperative care, but they do not address the most immediate life-threatening risk.

- Encourage early ambulation and physical therapy exercises: This is a crucial intervention for preventing VTE and other complications like pneumonia and ileus. However, it is a preventive measure, not an assessment for an active, life-threatening event. Once a clot has formed and embolized, ambulation will not reverse the PE.
- Monitor surgical site for signs of infection: Surgical site infection is a serious complication that can lead to prolonged hospitalization, sepsis, and implant failure. However, its progression is typically slower than that of a PE. A wound infection does not pose the same immediate threat to the airway and circulation as a pulmonary embolus.
- Maintain proper alignment and positioning of the affected leg: This intervention is vital for preventing prosthesis dislocation and promoting comfort. While improper positioning could theoretically contribute to venous stasis, the primary purpose is to protect the integrity of the new joint, not to prevent a systemic, life-threatening embolic event. The immediate risk of death from joint malalignment is negligible compared to a PE.

Clinical Application and Pathophysiology
The pathophysiology of VTE in TKA involves Virchow's triad: venous stasis (from immobility and tourniquet use during surgery), endothelial injury (from the surgical procedure itself), and a hypercoagulable state (as part of the body's physiological stress response to surgery). This triad creates a perfect environment for thrombus formation in the deep veins of the operated leg. The period around the second postoperative day is a high-risk window for a DVT to dislodge and become a PE.

Prophylactic anticoagulation is a cornerstone of care to mitigate this risk, with agents like rivaroxaban and low molecular weight heparin (LMWH) being commonly used . However, no prophylactic regimen is 100% effective, and a VTE can still occur ^[1]. This underscores why the nurse's vigilant assessment for the clinical manifestations of PE is non-negotiable and takes priority over other aspects of care. A nurse-led, systematic approach to monitoring and prevention is critical for improving patient outcomes . The best evidence for preventing DVT emphasizes a comprehensive strategy, but the nurse's role in early detection of a PE is the final safety net .