Fontan physiology - NYSORA

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Fontan physiology

Learning objectives

  • Describe the Fontan procedure and its indications
  • Manage patients with Fontan physiology


  • In a normal biventricular heart, the systemic and pulmonary circulations are in series and each circulation is supported by a ventricle
  • In patients with single-ventricle congenital heart disease, the two circulations are in parallel
  • These patients only survive because the systemic and pulmonary venous blood mix
  • The Fontan operation is a palliative procedure that places the two circulations in series
  • Selected patients should be in sinus rhythm, have a good ventricular function, and adequately sized pulmonary arteries


  • Contraindicated in the neonatal period due to high pulmonary vascular resistance
  • Staged approach to facilitate the progressive adaptation of the heart and lungs
    • Stage 1: Systemic-pulmonary shunt
      • Placement of a restrictive synthetic conduit between a major systemic central vessel and a proximal pulmonary artery
      • Patients with hypoplastic left heart syndrome: Conduit placed between the right ventricle and the left pulmonary artery
    • Stage 2: Superior cavopulmonary connection 
      • Bidirectional Glenn shunt or hemi-Fontan procedure 
      • Usually performed as soon as the pulmonary arteries have grown sufficiently to allow a low pulmonary vascular resistance (2-6 months)
      • Cardiopulmonary bypass and ligation of the previous systemic-pulmonary shunt
    • Stage 3: Completion
      • Usually performed at 1-5 years of age
      • Blood in the inferior vena cava is directed into the pulmonary circuit via an extracardiac conduit or via an intra-atrial baffle


  • Decreased exercise tolerance
  • Ventricular dysfunction
  • Arrhythmias
  • Shunts
  • Protein-losing enteropathy
  • Developmental deficits
  • Thromboembolism


fontan physiology, ecg, antibiotic prophylaxis, bacteremia, cardiology, fenestration, air embolus, fat embolus, oxygenation, cardiac rhythm, invasive arterial and central venous pressure, transesophageal echocardiography, contractility, thiopental, normovolemia, volatile, hypercarbia, hypoxemia, acidosis, intrathoracic pressure, opioid, doppler, atelectasis, hyperventilation, respiratory rate, inspiratory time, positive end-expiratory pressure, tidal volume, volume, cardiac output, inotropes, nausea, vomiting, thromboprophylaxis,

MAC, minimum alveolar concentration

Suggested reading

  • Jolley M, Colan SD, Rhodes J, DiNardo J. Fontan Physiology Revisited. Anesthesia & Analgesia. 2015;121(1).
  • Nayak S, Booker PD. The Fontan circulation. Continuing Education in Anaesthesia Critical Care & Pain. 2008;8(1):26-30.

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