A nurse is caring for a patient on the first postoperative day following total knee replacement surgery. Which assessment finding requires the most immediate nursing intervention?

Sudden chest pain and shortness of breath indicate pulmonary embolism, a life-threatening emergency requiring immediate intervention. Other findings are expected postoperative issues manageable with standard care.

Clinical Reasoning and Priority Setting

The correct answer is the sudden onset of severe chest pain and shortness of breath. This clinical presentation is a classic manifestation of a pulmonary embolism (PE), a life-threatening postoperative complication that requires the most immediate nursing intervention.

Pathophysiology and Clinical Significance

Following total knee replacement (TKA), patients are at a significantly increased risk for developing venous thromboembolism (VTE), which includes both deep vein thrombosis (DVT) and pulmonary embolism (PE) ^[3]. The surgical trauma, venous stasis from immobility, and a hypercoagulable state induced by the procedure collectively fulfill Virchow's triad, creating a perfect storm for thrombus formation in the deep veins of the lower extremities. When a portion of a DVT dislodges, it travels through the venous system to the right side of the heart and lodges in the pulmonary arterial circulation, creating a ventilation-perfusion mismatch. This acutely impairs gas exchange and increases pulmonary vascular resistance, which can rapidly lead to right heart failure and cardiovascular collapse. The sudden onset of severe chest pain and shortness of breath signals an acute obstruction in the pulmonary vasculature, making it a true medical emergency that takes precedence over all other findings.

Analysis of Assessment Findings

The other options, while requiring nursing attention, do not represent an immediate threat to the patient's airway, breathing, or circulation.

- Moderate incisional pain rated 6/10: Pain is an expected finding on the first postoperative day following a major orthopedic procedure. While effective pain management is a nursing priority for promoting mobility and recovery, it is not life-threatening and can be addressed after the emergency is managed.
- Serosanguineous drainage on the surgical dressing: A small to moderate amount of serosanguineous drainage is a normal postoperative finding. The nurse should monitor the drainage, outline the area on the dressing, and reassess, but this does not indicate an acute, life-threatening event.
- Inability to perform straight leg raises: This is an expected finding on the first postoperative day due to pain, quadriceps muscle inhibition, and surgical trauma. It is a focus for physical therapy and rehabilitation, not an immediate physiological emergency.

Evidence-Based Context for VTE Risk

The critical nature of this assessment finding is underscored by the high incidence of VTE in this patient population. A 10-year retrospective cohort study found that VTE remains a significant clinical concern following primary TKA, necessitating rigorous prophylactic strategies with agents like aspirin or direct oral anticoagulants (DOACs) . The clinical burden of this complication is substantial, and patients undergoing total joint arthroplasty are at an inherently increased risk for developing a postoperative VTE ^[3]. A multicenter study evaluating prophylactic anticoagulation after TKA further identified patient-related risk factors for thrombotic events, reinforcing that despite prophylaxis, breakthrough PEs can occur and must be recognized immediately . The nurse's role at the bedside is to identify the clinical signs of this breakthrough event, as prophylactic regimens are not 100% effective. The sudden onset of respiratory distress and chest pain in this context is a sentinel sign of a PE, a diagnosis that, while sometimes masquerading as other conditions, carries a high potential for rapid deterioration and mortality .