Clinical bottom line
Patients with Fontan physiology present unique anesthetic challenges during non-cardiac surgery due to their altered cardiovascular circulation and limited cardiac reserve. Careful perioperative planning focusing on maintaining adequate preload, minimizing pulmonary vascular resistance, and avoiding myocardial depression is essential to optimize outcomes. Current evidence, largely from case reports and expert reviews, suggests that individualized anesthetic strategies incorporating vigilant hemodynamic monitoring and tailored ventilation can reduce morbidity. However, data remain limited, and anesthesiologists should collaborate closely with cardiology and surgical teams for risk stratification and perioperative optimization.
What the evidence shows
Fontan physiology results from surgical palliation for single-ventricle congenital heart disease, creating a circulation in which systemic venous return flows passively into the pulmonary arteries without a subpulmonary ventricle. This unique hemodynamic state renders patients highly sensitive to changes in preload, pulmonary vascular resistance, and myocardial function (Staudt et al., 2019).
Anesthetic management principles emphasize preserving preload and systemic ventricular function while avoiding increases in pulmonary vascular resistance, which can compromise pulmonary blood flow and cardiac output (Kothandan Harikrishnan et al., 2015). General anesthesia with careful titration of anesthetic agents to minimize myocardial depression is commonly used, but sedation alone may be appropriate in select procedures to reduce hemodynamic perturbations (Bai et al., 2025).
Intraoperative monitoring strategies often include invasive arterial blood pressure measurement and central venous pressure monitoring to guide fluid management and vasoactive support (Staudt et al., 2019). Avoidance of positive pressure ventilation when possible or use of lung-protective ventilation strategies is recommended to prevent increases in pulmonary vascular resistance (Kothandan Harikrishnan et al., 2015).
Outcomes data are limited but suggest that morbidity and mortality rates are higher than in patients without congenital heart disease undergoing similar procedures (Strafford et al., 1991). However, with meticulous perioperative care, many patients tolerate non-cardiac surgery without major complications (Staudt et al., 2019).
While most literature focuses on pediatric patients, adult survivors of Fontan palliation undergoing non-cardiac surgery are increasingly encountered, necessitating ongoing adaptation of anesthetic approaches (Staudt et al., 2019).
Caveats and uncertainty
The evidence base for anesthetic management in Fontan physiology is primarily composed of case reports, small case series, and expert opinion rather than large controlled trials. This limits the ability to generalize findings or establish standardized protocols.
Variability in underlying cardiac anatomy, surgical modifications, and comorbidities among Fontan patients further complicates risk stratification and anesthetic planning. The impact of different anesthetic agents or techniques on long-term outcomes remains unclear.
Data on adult patients with Fontan physiology are particularly sparse, and their unique challenges related to chronic complications such as protein-losing enteropathy or arrhythmias require further study.
Additionally, the optimal intraoperative monitoring modalities and thresholds for intervention have not been rigorously defined.
How this may change practice
Anesthesiologists should maintain a high index of suspicion for hemodynamic instability in patients with Fontan physiology undergoing non-cardiac surgery and tailor anesthetic plans accordingly. Preoperative multidisciplinary evaluation including cardiology consultation is recommended to assess functional status and optimize medical therapy.
Intraoperative management should prioritize maintenance of preload, avoidance of factors increasing pulmonary vascular resistance (hypoxia, hypercarbia, acidosis), and careful selection and dosing of anesthetic agents to minimize myocardial depression. Use of invasive hemodynamic monitoring can guide fluid and vasoactive medication administration.
Postoperative care should include vigilant monitoring for heart failure, arrhythmias, and thromboembolic complications. Enhanced communication between anesthesia, surgery, and cardiology teams is essential to improve outcomes.
Further research is needed to develop evidence-based guidelines and to evaluate newer anesthetic techniques and monitoring technologies in this population.