Page 25 - CASA Bulletin of Anesthesiology Vol 9 (4) 2022 (3)

Vol. 9, No 4, 2022

Clinical pearls for anesthetic management of children with Fontan

physiology for non-cardiac surgery

Wenyu Bai, MD
Department of anesthesiology
University of Michigan Medical School
Section of Pediatric Anesthesiology
Ann Arbor, MI

The Fontan operation, first performed in 1969 , has remained
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the most commonly performed and effective procedure for children
born with single ventricle physiology. It is the last stage of single
ventricle palliation which effectively separates the pulmonary and
systemic circulations. The procedure connects the inferior vena cava
directly to the pulmonary arteries or to the previously created
superior cavopulmonary connection, which allows all the
deoxygenated systemic venous return to flow directly to the lungs.
The single ventricle (either morphologic left or right) receives
oxygenated blood from pulmonary veins, then pumps out
systematically. As the series of pulmonary and systemic circulation
is established, the cyanotic element is eliminated or reduced, and these children typically
maintain an oxygen saturation (SpO2) greater than 90%. Baseline higher central venous pressure
drives the Fontan circulation.
Patients with a Fontan physiology have significantly improved survival in the last 2 decades;
up to 89% survival has been reported lately . This success has created a growing population of
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children and adults with a single functional ventricle who may require non-cardiac
surgeries/procedures. Anesthetic management of such cases requires a thorough understanding of
the altered cardiovascular physiology, its implications on cardiac function and impacts of
anesthesia.

1. What are the common types of Fontan operation?

There have been several modifications to the original Fontan procedure, extracardiac conduit
(extracardiac Fontan) or intra-atrial baffle (lateral tunnel Fontan) are the 2 common types . In
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addition to provide better systemic oxygenation, Fontan procedure also reduces volume loading
of the systemic ventricle and reduces risk of paradoxical embolism through right to left shunt. A
communication (Fontan fenestration) may be made between the Fontan conduit or baffle and the
common atrium. This serves as a “pop-off” allowing to accommodate for a rise in systemic
venous pressure and a decrease in venous return and cardiac output in the case of a rise in
pulmonary vascular resistance (PVR). The fenestration will shunt some of deoxygenated blood
to the common atrium and maintain the cardiac output, at the cost of decreased arterial
oxygenation.
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