Anesthetic Management for Fontan Completion
For Fontan completion surgery, the recommended anesthesia technique should prioritize early extubation, spontaneous ventilation, and careful hemodynamic management to optimize pulmonary blood flow and cardiac output.
Understanding Fontan Physiology
- Fontan circulation creates a passive pulmonary blood flow system where systemic venous return flows directly to the pulmonary arteries without a pumping ventricle 1
- This unique physiology requires specific anesthetic considerations to maintain adequate preload, minimize pulmonary vascular resistance, and support the single ventricle 1
Preoperative Assessment
- Evaluate for risk factors including ventricular dysfunction, arrhythmias, thromboembolic events, and protein-losing enteropathy 1
- Assess pulmonary artery anatomy and pressures, as these significantly impact Fontan outcomes 1
- Review previous surgical stages (Glenn/bidirectional cavopulmonary anastomosis) and any complications 1
Anesthetic Technique
Induction
- Etomidate is commonly used (40% of cases) due to its hemodynamic stability 2
- Alternative options include esketamine (24%), midazolam (16%), or propofol (13%) in hemodynamically stable patients 2
- Avoid agents that significantly decrease systemic vascular resistance or myocardial contractility 1, 3
Maintenance
- Balanced anesthesia with volatile agents and opioids 2, 3
- Consider short-acting opioids like remifentanil to facilitate early extubation 2
- Regional anesthesia (caudal, epidural, or spinal) can be beneficial for post-operative pain management and to facilitate spontaneous ventilation 4
Ventilation Strategy
- Plan for early extubation (in operating room or within one hour postoperatively) 4, 5
- Use moderate hypoventilation to maintain mild hypercapnia, which can reduce pulmonary vascular resistance 1, 2
- Spontaneous ventilation improves hemodynamics by creating negative intrathoracic pressure that enhances pulmonary blood flow 4
Hemodynamic Management
- Standard monitoring plus direct arterial pressure monitoring 3
- Consider central venous pressure monitoring while recognizing its limitations in Fontan physiology 5
- Maintain adequate preload while avoiding volume overload 1, 3
- Use of inhaled nitric oxide (100% of cases) to reduce pulmonary vascular resistance 2
- Inotropic support typically includes:
Post-Bypass Management
- Maintain mild hypoventilation to reduce pulmonary vascular resistance 1, 2
- Continue inhaled nitric oxide to optimize pulmonary blood flow 2
- Titrate inotropes and vasopressors to maintain adequate cardiac output and systemic vascular resistance 2, 3
- Early transition to spontaneous ventilation significantly improves cardiac index and reduces mean pulmonary artery pressure 4
Postoperative Care
- Aim for early extubation to improve hemodynamics 4, 5
- Continue low-dose vasodilators (nitroglycerine, nitroprusside) and inotropes (dopamine) 4
- Consider anticoagulation or antiplatelet therapy to prevent thromboembolic complications 1
- Monitor for complications including bleeding, effusions, arrhythmias, and thromboembolic events 1, 5
Special Considerations
- Anesthesia for Fontan patients should be administered by or in collaboration with an anesthesiologist experienced in congenital heart disease 1
- Positive pressure ventilation can significantly impair pulmonary blood flow and cardiac output in Fontan circulation 4
- Pain-free spontaneous ventilation has been shown to significantly improve cardiac index from 3.25 to 5.05 immediately post-extubation 4
- Avoid prolonged immobilization which increases thrombotic risk 1
Common Pitfalls to Avoid
- Excessive positive pressure ventilation which impedes pulmonary blood flow 4, 3
- Inadequate pain control leading to increased pulmonary vascular resistance 4
- Volume overload or depletion, both of which can compromise Fontan circulation 3
- Failing to plan for early extubation, which is associated with improved outcomes 4, 5