Board Things: Fontan Cir...
Highlights
- Board things: Fontan Circulation goals 🧵
Fontan physiology is usually the end-result of palliative procedures (of which there are several variations) for patients born with single-ventricle physiology.
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- Examples of single ventricular physiology:
- Hypoplastic left heart syndrome
- Pulmonary atresia
- Tricuspid atresia
- Ebstein anomaly
- Double outlet RV
Etc. (View Tweet)
- This is usually completed step wise, starting with a Norwood procedure/Sano shunt hybrid (reconstructs a neoaorta and provides shunt connection from RV to PA), followed by a Glenn (shunt takedown with connection of SVC to PA), then a Fontan (IVC also connected to PA).
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- Given that more and more of these kiddos are living into adulthood (🎉), the likelihood of seeing these patients for noncardiac surgery is increasing.
Important to try to review a pre-op echo! Consider invasive monitoring (TEE/art line). Most are anticoagulated - consider labs! (View Tweet)
- Goal 1: Maintain preload. These patients are very preload dependent. Minimize NPO time. Augment w volume if dehydrated. TEE can be helpful for assessment of volume status.
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- Goal 2: Minimize PVR. These patients do not have an effective RV and their pulmonary blood flow is all passive. Increases in PVR (hypercarbia, acidosis, hypoxia, pain, high PEEP etc) can be disastrous.
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- Goal 3: Maintain sinus rhythm as able. These patients benefit from optimized diastolic filling. That said, it is not uncommon for them to have arrhythmia histories, particularly if their Fontan begins to fail. (View Tweet)
- Goal 4: Minimize intrathoracic pressure. If able, keeping patient spontaneous will optimize pulmonary blood flow (think regional, MAC, LMA etc). If GETA with paralysis is absolutely necessary, utilize lowest possible pressures for ventilation.
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- Goal 4 ctd: That said, remember spontaneous ventilation under sedation/GA with LMA may risk hypercarbia. Important to weigh the risks/benefits of PPV with normocarbia vs. spontaneous vent and pain/hypercarbia.
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- Goal 5: For most, the goals for contractility and afterload will be to just maintain both at homeostasis. Failing Fontans (which are a topic all their own) may likely require inotropic support.
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