What is the management of an intraoperative pulmonary embolism?

Management of Intraoperative Pulmonary Embolism

Immediate recognition and aggressive management of intraoperative pulmonary embolism with a multidisciplinary approach is essential, with treatment options including anticoagulation, thrombolysis, surgical embolectomy, or catheter-directed interventions based on hemodynamic stability.

Clinical Presentation and Diagnosis

Intraoperative PE typically presents with:

• Sudden hypotension and tachycardia
• Decreased end-tidal CO2
• Hypoxemia despite increased oxygen delivery
• Increased central venous pressure
• Right ventricular dysfunction on echocardiography

Transesophageal echocardiography (TEE) is the most valuable diagnostic tool during surgery, allowing real-time assessment of right ventricular function, pulmonary artery obstruction, and intracardiac thrombi 1.

Management Algorithm

Step 1: Initial Stabilization

• Provide supplemental oxygen to correct hypoxemia 2
• Maintain hemodynamic support:
  • Administer modest fluid challenge (500 mL) 2
  • Avoid aggressive fluid administration to prevent RV overdistension 2
  • Start vasopressors (norepinephrine) for persistent hypotension 2
  • Consider dobutamine for low cardiac output with normal blood pressure 2
• Avoid high tidal volumes (use ~6 mL/kg) and high PEEP to prevent further RV strain 2

Step 2: Immediate Anticoagulation

• Administer unfractionated heparin (UFH) as first-line therapy:
  • Initial bolus: 80 units/kg IV 2, 3
  • Follow with continuous infusion according to weight-based nomogram 4
• Monitor aPTT to maintain 1.5-2 times normal value 3

Step 3: Risk Stratification and Further Management

For High-Risk PE (with hemodynamic instability):

1. Systemic Thrombolysis (if no absolute contraindications):

   • Alteplase 100 mg over 2 hours 4, 2
   • Consider reduced-dose protocols in high bleeding risk situations 4

2. Surgical Embolectomy (if thrombolysis is contraindicated or failed):

   • Performed via median sternotomy with normothermic cardiopulmonary bypass 4
   • Aortic cross-clamping should be avoided 4
   • Bilateral PA incisions to remove clots under direct vision 4

3. Catheter-Directed Interventions (when surgical options unavailable):

   • Options include thrombus fragmentation, rheolytic thrombectomy, suction thrombectomy, or rotational thrombectomy 4
   • Consider for patients with absolute contraindications to thrombolysis 4

4. ECMO Support:

   • Consider venoarterial ECMO for refractory circulatory collapse 2, 5
   • Can serve as bridge to definitive therapy in critically unstable patients 5

For Intermediate-Risk PE (with RV dysfunction but hemodynamically stable):

• Continue anticoagulation with UFH 2
• Monitor closely for signs of deterioration
• Consider catheter-directed thrombolysis if clinical deterioration occurs 4

Special Considerations for Intraoperative Setting

• Bleeding Risk: Balance the need for anticoagulation against surgical bleeding risk 6
• Surgical Field: Consider the nature of the surgical field when deciding on anticoagulation intensity
• Anesthesia Management: Maintain normothermia, avoid hypotension, optimize ventilation
• Multidisciplinary Approach: Involve cardiac surgery, interventional radiology, and critical care as needed 2

Contraindications to Thrombolysis

Absolute contraindications include 4:

• Previous intracranial hemorrhage
• Known structural cerebral vascular lesion
• Ischemic stroke within 3 months
• Active bleeding
• Recent major surgery (especially neurosurgery)

Post-Acute Management

• Transfer to ICU for close monitoring
• Continue anticoagulation for at least 3 months 2
• Consider extended anticoagulation for unprovoked PE 2
• Follow-up evaluation 3-6 months after acute event 2

Pitfalls and Caveats

• Delay in diagnosis significantly increases mortality
• Aggressive fluid administration can worsen RV failure
• Systemic thrombolysis carries significant bleeding risk in the perioperative setting 7
• Consider reduced-dose thrombolysis protocols in high bleeding risk situations 7
• Surgical embolectomy requires cardiopulmonary bypass, which may not be immediately available

The management of intraoperative PE requires rapid decision-making and a tailored approach based on hemodynamic status, bleeding risk, and available resources. The European Society of Cardiology guidelines provide a framework for management, but the unique challenges of the intraoperative setting require special consideration of the risks and benefits of each intervention.