NGN Case Study 2: Post-Operative Complications

Post-operative complications are among the most commonly tested topics on the NCLEX because they require nurses to integrate assessment skills, pathophysiology knowledge, and rapid clinical decision-making. Deep vein thrombosis (DVT) and pulmonary embolism (PE) are particularly high-yield because they can be life-threatening if not recognized and managed promptly.

This NGN case study follows a patient through the development of a DVT with progression to suspected PE after total hip replacement surgery. Each step is mapped to the Clinical Judgment Measurement Model (CJMM), demonstrating how you should approach similar scenarios on the exam. Pay close attention to the delegation considerations, as the NCLEX frequently tests your understanding of scope of practice in post-operative care.

Patient Presentation

Clinical Scenario

Patient: Robert Martinez, a 55-year-old male, is post-operative day (POD) 2 following a left total hip arthroplasty (replacement). The surgery was performed under general anesthesia and lasted approximately 2.5 hours. He has been ambulating with physical therapy assistance but reports increasing discomfort in his left calf that is different from his surgical site pain.

Medical History: Obesity (BMI 34), hypertension (controlled with amlodipine 10 mg daily), hyperlipidemia (managed with atorvastatin 40 mg daily), former smoker (quit 5 years ago, 20 pack-year history), osteoarthritis (indication for hip replacement). No prior history of DVT or PE. No known drug allergies.

Surgical Details: Prophylactic enoxaparin 40 mg subcutaneous daily was initiated 12 hours post-operatively per orthopedic protocol. Sequential compression devices (SCDs) ordered for bilateral lower extremities when in bed. Patient reports he has been removing the SCDs overnight because they are uncomfortable.

Initial Assessment Data (POD 2, 0800)

Morning Vital Signs

Temperature

99.1°F (37.3°C)

Heart Rate

88 bpm

Blood Pressure

134/82 mmHg

Respiratory Rate

18 breaths/min

SpO2

96% on room air

Assessment Findings

Surgical site: dressing clean, dry, and intact; no signs of infection
Hemovac drain: 30 mL serosanguineous drainage in past 8 hours
Left calf: patient reports new onset aching pain, rated 4/10, separate from hip pain
Left calf circumference: 38 cm; right calf circumference: 34 cm (4 cm difference)
Left calf warm to touch with mild erythema and pitting edema
Positive Homans sign (calf pain with dorsiflexion -- though note this test has low sensitivity)
Pedal pulses palpable bilaterally (2+)
Pain with ambulation, patient reluctant to continue physical therapy

Step 1: Recognize Cues

CJMM Skill: Recognize Cues

Identifying the clinically significant findings from the assessment:

Unilateral calf swelling (4 cm difference): A difference of more than 3 cm between calves is considered clinically significant and is a hallmark finding of DVT. This is the most specific physical finding.
Calf pain separate from surgical site: The patient clearly differentiates this pain from his hip pain, suggesting a new pathological process. The aching quality is characteristic of venous congestion.
Warmth, erythema, and edema of left calf: The triad of warmth, redness, and swelling in a single extremity is classic for deep vein thrombosis. These findings result from venous obstruction and the inflammatory response.
Positive Homans sign: While this test has poor sensitivity and specificity (and is no longer recommended as a definitive diagnostic tool), it provides additional supporting evidence in the context of other findings.
Risk factor profile: Multiple DVT risk factors are present -- recent major orthopedic surgery, obesity, smoking history, prolonged immobility, general anesthesia lasting over 2 hours, and non-compliance with SCDs.
SCD non-compliance: The patient has been removing his sequential compression devices at night, reducing the effectiveness of mechanical DVT prophylaxis during a period of sustained immobility.

Step 2: Analyze Cues

CJMM Skill: Analyze Cues

Interpreting what the recognized cues mean when considered together:

Virchow's Triad analysis: All three components of Virchow's Triad are present in this patient. Venous stasis (immobility post-surgery, SCD non-compliance), endothelial damage (surgical trauma), and hypercoagulability (post-operative inflammatory response, obesity) create the ideal conditions for thrombus formation.
Clinical probability assessment: Using the Wells Criteria for DVT, Mr. Martinez scores highly: active cancer (0 points) + paralysis/immobilization (1 point) + bedridden >3 days or major surgery (1 point) + localized tenderness along the deep venous system (1 point) + entire leg swollen (0 -- only calf) + calf swelling >3 cm (1 point) + pitting edema (1 point) + collateral superficial veins (0 points) + previously documented DVT (0 points) + alternative diagnosis as likely (-2 points, not applicable here). This yields a Wells score suggesting moderate to high probability.
Risk of progression: Without adequate treatment, proximal DVT carries a 30-50% risk of pulmonary embolism. The left lower extremity is the more common site for DVT, and the post-surgical timing (POD 2) is within the highest-risk window.
Prophylaxis adequacy: Despite receiving enoxaparin prophylaxis, the dose (40 mg daily) is prophylactic rather than therapeutic. Combined with SCD non-compliance, prophylaxis was insufficient to prevent thrombus formation.

Step 3: Prioritize Hypotheses

CJMM Skill: Prioritize Hypotheses

Ranking the differential diagnoses from most to least likely:

Deep Vein Thrombosis (HIGHEST PRIORITY): Unilateral calf swelling, warmth, erythema, pain with multiple DVT risk factors strongly support this diagnosis. The 4 cm circumference difference is highly suggestive. This is the most likely explanation and carries the most significant risk if left untreated (PE).
Superficial thrombophlebitis: Could present similarly with localized redness, warmth, and tenderness, but typically involves a palpable, cord-like vein near the surface. Less dangerous than DVT but still requires evaluation because it can propagate to the deep venous system.
Post-operative edema (normal): Some degree of swelling is expected after hip surgery, but it is typically bilateral or localized to the surgical site. The unilateral nature and 4 cm difference make isolated post-operative edema unlikely as the sole explanation.
Cellulitis: Possible given the warmth and erythema, but typically presents with more diffuse redness, potential skin breakdown, and often fever. The location (calf rather than surgical site) and unilateral swelling pattern favor DVT over cellulitis.
Muscle strain or hematoma: A less likely alternative, though the patient has been ambulating with physical therapy. A hematoma in the calf could cause swelling and pain but would not typically present with the classic DVT triad.

Step 4: Generate Solutions

CJMM Skill: Generate Solutions

Identifying appropriate diagnostic and therapeutic interventions:

Venous duplex Doppler ultrasound: The gold standard initial diagnostic test for DVT. Non-invasive, available at bedside, and highly sensitive (95%) and specific (98%) for proximal DVT. Should be ordered stat.
D-dimer level: While useful for ruling out DVT in low-probability patients, D-dimer is often elevated post-operatively and therefore less useful in this context. However, a normal D-dimer would help rule out the diagnosis.
Transition to therapeutic anticoagulation: If DVT is confirmed, switch from prophylactic enoxaparin (40 mg daily) to therapeutic dosing (1 mg/kg BID) or initiate IV heparin infusion with aPTT monitoring.
Bed rest with leg elevation: Elevate the affected limb above heart level to promote venous return and reduce edema. Limit ambulation until anticoagulation is therapeutic to reduce clot dislodgement risk.
Pain management: Assess pain level and administer prescribed analgesics. Avoid IM injections in the affected extremity. Apply warm compresses (not cold) to the affected calf to promote circulation.
Monitor for PE signs: Assess for sudden onset dyspnea, chest pain, tachycardia, tachypnea, decreased SpO2, hemoptysis, or anxiety -- all signs of pulmonary embolism.
Patient education on SCD compliance: Reinforce the importance of wearing SCDs continuously when in bed. Explain the relationship between non-compliance and DVT development.

Clinical Progression: 4 Hours Later

Evolving Clinical Picture

Doppler ultrasound confirmed a proximal DVT in the left popliteal vein. IV heparin infusion was initiated per protocol. Four hours later, the nurse is called to the bedside because Mr. Martinez is experiencing new symptoms.

New complaints: Sudden onset of sharp, pleuritic chest pain rated 7/10, worsening with deep inspiration. Shortness of breath that started abruptly while repositioning in bed. Feeling anxious and states "something is really wrong."

Updated Vital Signs (1200)

Temperature

100.2°F (37.9°C)

Heart Rate

108 bpm

Blood Pressure

142/88 mmHg

Respiratory Rate

24 breaths/min

SpO2

92% on room air

Lab Results

D-dimer	2,450 ng/mL (elevated)
PT/INR	12.8 sec / 1.0 (normal)
aPTT	28 sec (normal)
CBC - Hemoglobin	11.2 g/dL (slightly low)
CBC - Platelets	245,000/mcL (normal)
BMP - Creatinine	1.1 mg/dL (normal)

Step 5: Take Action

CJMM Skill: Take Action

With suspected pulmonary embolism, immediate and decisive action is required. Prioritized interventions:

Maintain airway and apply high-flow oxygen -- SpO2 of 92% requires supplemental oxygen. Apply via non-rebreather mask at 10-15 L/min targeting SpO2 above 94%.
Position patient upright (high Fowler's) -- To optimize respiratory mechanics and reduce venous return to an already strained right ventricle.
Activate rapid response team (RRT) -- The sudden change in status with hemodynamic instability warrants immediate team response. Do not delay for further assessment.
Ensure continuous cardiac monitoring -- Monitor for right heart strain patterns (S1Q3T3 on ECG, sinus tachycardia, right bundle branch block).
Verify IV heparin infusion is running -- Anticoagulation is critical. Verify the infusion rate, ensure the line is patent, and confirm the aPTT is within therapeutic range (typically 1.5-2.5 times the control value).
Obtain stat ABG, troponin, and BNP -- ABG to assess gas exchange (expect hypoxemia with hypocapnia from hyperventilation). Troponin and BNP to assess right ventricular strain.
Prepare for CT pulmonary angiography (CTPA) -- The definitive diagnostic test for PE. Coordinate with radiology for emergent imaging. Ensure IV access is adequate for contrast injection.
Maintain bed rest -- Strict bed rest to prevent further clot dislodgement. Reassure the patient and reduce anxiety, which worsens oxygen demand.
Notify the surgeon and attending physician -- Use SBAR communication. Situation: patient with confirmed DVT now showing signs of PE. Background: POD 2 from total hip arthroplasty. Assessment: acute respiratory distress with hemodynamic changes. Recommendation: emergent CTPA and possible ICU transfer.

Delegation Considerations

Delegation and Team Communication

The NCLEX frequently tests delegation in post-operative settings. Understanding scope of practice is essential:

RN responsibilities (cannot delegate): Initial assessment, vital sign interpretation, IV heparin management, provider notification via SBAR, patient education about PE signs, care plan development, and medication administration (heparin is a high-alert medication).
Tasks appropriate for LPN/LVN: Subsequent vital sign monitoring (after RN establishes baseline and parameters), documenting intake and output, reinforcing education already provided by the RN, applying SCDs.
Tasks appropriate for UAP/CNA: Obtaining vital signs (but RN must interpret), measuring calf circumferences (with RN guidance on technique), positioning assistance, ambulation assistance (when cleared), reporting changes to the RN immediately.
Critical rule: Assessment, teaching, evaluation, and care of unstable patients cannot be delegated. In this scenario, Mr. Martinez is unstable -- the RN must remain at the bedside and provide direct care while delegating routine tasks for other patients to team members.

Step 6: Evaluate Outcomes

CJMM Skill: Evaluate Outcomes

Assessment of treatment effectiveness and ongoing monitoring:

Respiratory status: Is SpO2 improving on supplemental oxygen? Is the patient's work of breathing decreasing? Can supplemental oxygen be weaned? Improving oxygenation suggests the PE is not massive and anticoagulation is preventing further embolization.
Hemodynamic stability: Is heart rate trending down toward baseline? Is blood pressure stable? Resolution of tachycardia is one of the earliest indicators that the right ventricle is recovering from the acute pressure overload.
Anticoagulation effectiveness: aPTT drawn every 6 hours until therapeutic (1.5-2.5 times control, typically 60-80 seconds). Adjust heparin infusion per protocol. Therapeutic anticoagulation prevents clot propagation and allows the body's fibrinolytic system to gradually dissolve the embolus.
DVT progression: Monitor left calf circumference, pain level, and distal perfusion. Effective anticoagulation should prevent clot extension and gradually reduce swelling.
Complications monitoring: Watch for signs of bleeding (heparin therapy), hemodynamic deterioration (massive PE), or recurrent embolization. Assess surgical site for increased drainage or hematoma formation, as anticoagulation increases bleeding risk post-operatively.
Patient understanding: Evaluate the patient's understanding of the importance of SCD compliance, anticoagulation therapy, and reporting new symptoms immediately. Address the earlier non-compliance with education about the direct relationship between SCD removal and DVT development.

NCLEX Testing Strategies for DVT/PE Cases

Know Virchow's Triad: Venous stasis, endothelial damage, and hypercoagulability. Identify which elements are present in any given scenario.
DVT = ultrasound, PE = CTPA: Know the appropriate diagnostic test for each condition. Do not confuse them.
Never massage a suspected DVT: This is a common distractor on the exam. Massage can dislodge the clot and cause PE.
Position matters: DVT -- elevate the affected extremity. PE -- high Fowler's position to optimize breathing.
Heparin safety: Know the antidote (protamine sulfate), monitoring parameter (aPTT), and signs of bleeding. Heparin is a high-alert medication that requires independent double-checks at many institutions.
Delegation questions: When prioritizing, always assess the unstable patient first. The RN must evaluate this patient before delegating any other tasks.

Common Mistakes on DVT/PE Questions

Applying ice to a DVT site -- warmth (warm compresses) is appropriate, not cold.
Encouraging ambulation when DVT is suspected -- bed rest with leg elevation is indicated until anticoagulation is initiated and therapeutic.
Administering aspirin instead of heparin for acute DVT/PE -- aspirin is not a first-line treatment for venous thromboembolism.
Delaying rapid response activation to gather more assessment data when PE signs are present -- activate RRT first, then continue assessment.
Forgetting to assess the surgical site for bleeding after initiating therapeutic anticoagulation.

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